One of the most important components of an acoustic system is the speakers. Moreover, not only their technical characteristics are of great importance, but also the material from which they are made. The fact is that the material affects the sound quality. In addition, their cost, and therefore the cost of the entire speaker system, directly depends on what the speakers are made of. In this article we will look at the advantages and disadvantages of the different types of material that speakers can be made from.
Acoustic systems - what are they?
The speaker system is the most important component in any audio equipment. Without it, sound is unthinkable at all, since it is responsible for converting an electrical impulse directly into a sound signal. There are different classifications of acoustic systems:

• Based on the method of connection to the amplifier, acoustics are divided into active (the amplifier is built into the system) and passive (the amplifier is external).
• In terms of size, acoustic systems can be bookshelf or floor-standing.
• Based on cost, acoustics are divided into categories: budget, Hi-Fi and Hi-End classes.

Separately, we note all-weather systems, which are distinguished by their ability to work even in the most extreme conditions: outdoors, in the rain, at high and low temperatures.
Another special category is Lifestyle acoustics, which are distinguished by a combination of exclusive design and high-quality sound.
Basic requirements for a high-quality acoustic system
The requirements for an acoustic system largely depend on the purposes for which you plan to use it. In particular, if the speakers are intended for watching videos, their main task is to accurately convey the voices of the characters, music and audio effects. But the most stringent requirements are placed on systems designed for listening to music. In any case, one rule applies: the less distortion, the better.
Ideally, the speaker system should have the following characteristics:

• Having sufficient power will be one of the guarantees of minimal sound errors.
• Reproduce the audio frequency band accessible to the human ear - from 20 Hz to 20,000 Hz.
• Accurately convey the sound stage - both when listening to stereo and multi-channel sound, which is traditionally equipped with most home theaters today.
• Correspond to the size of the room in terms of acoustic pressure, more often called volume.

Another important requirement: acoustics must satisfy the emotional and aesthetic needs of the buyer not only with their sound, but also with their appearance.
Why is the acoustic enclosure important?
The sound in the speakers is converted from an electrical impulse into a sound one. In this case, the main load falls on the speakers and filters. But without a quality case, all the hard work these elements do can simply come to naught. Here are the basic requirements for a high-quality acoustic enclosure:

• It must be made of high quality material
• During the manufacture of the housing, all technological standards and parameters must be observed.
• The housing must be rigid enough to provide a good combination of absorption/reflection of sound waves of a certain frequency and power.

Modern speaker manufacturers use a wide variety of materials to create them. For example, there are speakers with glass bodies that create the visual effect of a waterfall. Some open-type speaker systems do not have a cabinet at all.
The main materials for the production of speaker cabinets today are plastic, wood, and metal. Let's take a closer look at them.
Plastic

Plastic speakers are usually the most affordable. This material has been used for quite some time, and its features make it possible to produce speakers of various shapes. Low cost is one of the reasons why budget acoustics are usually equipped with plastic speakers.
Among the shortcomings we note:

• numerous shortcomings in sound,
• rattling at medium and high volumes,
• mid-frequency resonances.

But this does not mean that all plastic speakers transmit low quality sound. Many manufacturers make high-quality acoustics from plastic. For this purpose, special technologies and proprietary developments are used, which, naturally, are not included in the category with the most affordable prices. For example, the German company Bell-Audio has patented a technology for manufacturing cases from two-layer monolithic plastic, whose properties are not inferior to twenty layers of Karelian birch.
Thus, when choosing a speaker system, it is better to pay attention to the quality of the plastic from which the body is made.
Tree

This material is considered the best for the production of speaker systems.
But there are some subtleties here. The best speakers are made from solid wood, but it is used quite rarely and only in elite segments, since it requires rather complex processing. Ideally, raw materials should be selected at the cutting stage, kept for a long time, and dry naturally, without artificial acceleration. Almost all operations must be done manually. Therefore, the elitism and high cost of real wooden speakers is understandable.
Today, in the production of wooden cabinets, plywood, chipboard (chipboard) and MDF (medium density fiberboard) are most often used.
Plywood.
High-quality plywood, as a rule, has many layers - from 12 to more. Pros: good absorption properties, lighter than chipboard and MDF, less susceptible to delamination. But high-quality plywood is an expensive material, so its use in mass production is limited.
Chipboard.
Significantly cheaper than solid wood and plywood. At the same time, it has certain advantages. In particular, slabs with a thickness of more than 16 mm have a high density, and this characteristic helps to reduce cabinet resonances. In addition, due to its structure, chipboard does not introduce its own overtones.
Among the disadvantages: the problem of delamination and moisture absorption, which the fiberboard is susceptible to. It can be solved using special painting or cladding with various materials.
Given its availability and good acoustic characteristics, chipboard is used by many manufacturers.
MDF.
The most common material. It appeared as a result of improvements in the technologies used in the production of chipboards. MDF is made from dried wood fibers, treated with synthetic binders and formed into a carpet, followed by hot pressing, and lined with natural or synthetic veneer.
Despite the simple technology of production and processing, even medium-density boards can surpass wood in resistance to mechanical damage and moisture resistance.
The main advantages of MDF are good absorption of sound vibrations and provision of mechanical rigidity to the speaker body. This explains the frequency of use in the production of speakers of various price categories.
Metal

Typically, aluminum, or rather its alloys, are used to make speaker housings. These materials have good mechanical properties: rigidity, density and lightness. According to many experts, aluminum can reduce resonance and improve the transmission of high frequencies in the sound spectrum. In addition, when exposed to air, this metal is covered with a thin, colorless film, which protects it from oxidation. Therefore, it is often used to make all-weather systems.
Due to their flexibility, aluminum and its alloys are often used to make Lifestyle speakers. But there is also a drawback that experienced “audiophiles” note: the sound of such systems has something “metallic” in it.
Which material should you prefer?
Important note: none of the materials used in the manufacture of speaker systems by themselves provide high-quality sound.
What matters is not what the acoustics are made of, but how exactly this happened. Only by observing all technological parameters during the production and assembly of the cabinet, and then by fine-tuning and fine-tuning the electronic components, can you obtain the ideal sound of the speaker system.
In addition, ideal sound is, in many ways, an individual characteristic. Therefore, when choosing speakers, be sure to focus on your personal emotional perception. After all, even the most expensive speakers may not transmit sound the way you would like to hear it.
We wish you happy shopping!

This new series of articles is dedicated to acoustic systems. Due to the fact that the topic is extremely broad, we decided to create a series of publications reflecting the selection criteria when purchasing speakers. This article focuses on the acoustic properties of cabinet materials and acoustic design. The post will be especially useful for those who are faced with choosing speakers, and will also provide information for people who want to create their own speakers in the process of their DIY experiments.

There is an opinion that one of the decisive factors affecting the sound of speakers is the material of the housing. PULT experts believe that the importance of this factor is often exaggerated, however, it is truly important and cannot be written off. An equally important factor (among many others) that determines the sound of speakers is the acoustic design.

Material: from plastic to granite and glass

Plastic - cheap, cheerful, but resonates

Plastic is often used in the production of budget speakers. The plastic body is lightweight, significantly expands the possibilities of designers; thanks to casting, almost any shape can be realized. Different types of plastics differ greatly in their acoustic properties. In the production of high-quality home acoustics, plastic is not very popular, but it is in demand for professional samples, where low weight and mobility of the device are important.

(for most plastics the sound absorption coefficient ranges from 0.02 - 0.03 at 125 Hz to 0.05 - 0.06 at 4 kHz)

A typical representative of the “plastic brotherhood” in home acoustics with decent characteristics and an attractive price: Bookshelf acoustics

Tree - from felling to golden ears

Due to its good absorption properties, wood is considered one of the best materials for making speakers.

(the sound absorption coefficient of wood, depending on the species, ranges from 0.15 – 0.17 at 125 Hz to 0.09 at 4 kHz)

Solid wood and veneer are used relatively rarely for the production of speakers and, as a rule, are in demand in the HI-End segment. Wooden speakers are gradually disappearing from the market due to low manufacturability, instability of the material and prohibitively high cost.

It is interesting that in order to create truly high-quality speakers of this type that meet the requirements of the most sophisticated listeners, technologists must select material at the cutting stage, as in the production of acoustic musical instruments. The latter is related to the properties of wood, where everything is important, from the area where the tree grew, to the humidity level of the room where it was stored, the temperature and duration of drying et cetera. The latter circumstance makes DIY development difficult; in the absence of special knowledge, an amateur creating a wooden speaker is doomed to act by trial and error.

Manufacturers of such acoustics do not report how the situation really is and whether the described conditions are met, and accordingly, any wooden system requires careful listening before purchasing. With a high degree of probability, two speakers of the same model from the same breed will sound slightly different, which is especially important for some demanding listeners.

Columns from an array of valuable rocks are available in units, their cost is astronomical. Everything yours truly has heard sounds excellent. However, in my subjectively pragmatic opinion, it is disproportionate to the cost. Sometimes, well-designed enclosures made of plywood and MDF have no less musicality, but for many audiophiles “not wood” = “not true hi-end”, and for some, “not wood” simply does not allow the status or spoils the interior design.

One of the best wooden systems in our catalog is this:
Floor-standing acoustics (price appropriate)

Chipboard – thickness, density, humidity

Chipboard is comparable in cost to plastic, but does not have a number of disadvantages that are inherent in plastic cases. The most significant problem of chipboard is low strength, with a fairly high mass of material.

Sound absorption in chipboard is non-uniform and in some cases low- and mid-frequency resonances may occur, although the likelihood of their occurrence is lower than in plastic. Plates with a thickness of more than 16 mm, which reach the required density, can effectively dampen resonances. It should be noted that, as in the case of plastic, the properties of a particular chipboard are of great importance. It is important to take into account the density and humidity of the material, since different chipboards differ in these parameters. Thick, dense chipboards are often used to create studio monitors, which indicates the demand for the material in the production of professional equipment.

On a note, for fellow DIY fraternity, chipboard with a density of at least 650 - 820 kg/m³ (with a board thickness of 16 - 18 mm) and a humidity of no more than 6-7% is well suited for creating speakers. Failure to comply with these conditions will significantly affect the sound quality and reliability of the speakers.

Among the worthy chipboard options for home speakers, our experts highlight:

MDF: from furniture to acoustics

Today, MDF (Medium Density Fiberboard) is used everywhere, among other things, MDF is one of the most common modern materials for the production of acoustics.

The reason for the popularity of MDF was the physical properties of the material, namely:

• Density 700 - 800 kg/m³
• Sound absorption coefficient 0.15 at 125 Hz – 0.09 at 4 kHz
• Humidity 1-3%
• Mechanical strength and wear resistance

The material is cheap to produce, has acoustic properties comparable to those of wood, while the resistance of the boards to mechanical damage is somewhat higher. MDF has sufficient acoustic rigidity of the speaker cabinet, and sound absorption meets the parameters necessary for creating HI-FI acoustics.

Visual difference between MDF and chipboard

There are a lot of wonderful systems among MDF acoustics; the following are optimal in terms of price/quality ratio:

Acoustic design - boxes, tubes and horns

Acoustic design is no less important for accurate sound transmission in speakers. The most common types (it is natural that certain types can be combined depending on the specific model, for example, the bass-reflex part of the speaker is responsible for the low and mid-frequency range, and a horn is built for the high ones).

Bass reflex - the main thing is the length of the pipe

A bass reflex is one of the most common types of acoustic design. This method allows, with the correct calculation of the length of the pipe, the cross-section of the hole and the volume of the housing, to obtain high efficiency, an optimal frequency ratio, and amplify low frequencies. The essence of the phase inverter principle is that on the back of the body there is a hole with a pipe, which allows you to create low-frequency oscillations in phase with the waves created by the front side of the diffuser. Most often, the bass reflex type is used when creating 2.0 and 4.0 systems.

To make calculations easier when creating your own speaker, it is convenient to use special calculators; one of the convenient ones is provided at the link.

In the HI-END philosophy, there are extremely radical, uncompromising judgments about bass reflex systems; I present one of them without comment:

“Enemy No. 1 is, of course, nonlinear amplification elements in the sound path (then everyone, to the best of their education, understands which elements are more linear and which are less). Enemy No. 2 is the bass reflex. the bass reflex is designed to show off, it should allow a small cheap speaker to record 50... 40... 30 in the passport, and what a trifle even 20 Hz at a level of -3 dB! But the lower frequency range of the bass reflex ceases to be relevant to music; more precisely, the bass reflex itself is a pipe singing its own melody.”

Closed box - a coffin for extra low

The classic option for many manufacturers is a regular closed box with speaker diffusers brought to the surface. This type of acoustics is quite simple to calculate, but the efficiency of such devices is not great. Also, the boxes are not recommended for lovers of characteristically pronounced lows, since in a closed system without additional elements that can enhance the lows (bass reflex, resonator), the frequency spectrum from 20 to 350 Hz is poorly expressed.

Many music lovers prefer the closed type, since it is characterized by a relatively flat frequency response and realistic “honest” transmission of the reproduced musical material. Most studio monitors are created in this acoustic design.

Band-Pass (closed resonator box) – the main thing is not to buzz

Band-Pass became widespread in the creation of subwoofers. In this type of acoustic design, the emitter is hidden inside the housing, while the insides of the box are connected to the external environment by bass reflex pipes. The task of the emitter is to excite low-frequency oscillations, the amplitude of which increases many times thanks to the bass reflex pipes.

Open body - no extra walls

A relatively rare type of acoustic design today, in which the rear wall of the housing is repeatedly perforated or completely absent. This type of design is used to reduce the number of housing elements that affect the frequency response of the speakers.

In an open box, the front wall has the most significant influence on the sound, which reduces the likelihood of distortion introduced by other parts of the case. The contribution of the side walls (if any are present in the structure), given their small width, is minimal and amounts to no more than 1-2 dB.

→

Horn design - problematic loudness champions

Horn acoustic design is more often used in combination with other types (in particular for the design of high-frequency emitters), however, there are also original 100% horn designs.

The main advantage of horn speakers is their high volume when combined with sensitive speakers.

Most experts, not without reason, are skeptical about horn acoustics, for several reasons:

• Structural and technological complexity, and accordingly, high requirements for assembly
• It is almost impossible to create a horn speaker with a uniform frequency response (with the exception of devices costing 10 kilobucks and above)
• Due to the fact that the horn is not a resonating system, it is impossible to correct the frequency response (a minus for DIYers who intend to copy a Hi-end horn)
• Due to the peculiarities of the waveform of horn acoustics, the sound volume is quite low
• Overwhelmingly relatively low dynamic range
• It produces a large number of characteristic overtones (considered a virtue by some audiophiles).

Horn systems have become the most popular among audiophiles in search of “divine” sound. The tendentious approach allowed the archaic horn design to get a second life, and modern manufacturers were able to find original solutions (effective, but extremely expensive) to common horn problems.

→
To be continued...

The negative impact of extraneous sounds on the human condition has long been proven. In this regard, many special rules have been developed to determine the permissible values ​​of “sound garbage”.

For example, due to background noise reaching 40 dBA, a person will begin to have problems sleeping, and with systematic noise above 60 dBA, structural changes in the body will occur in 90 cases out of 100. To minimize or completely eliminate the risk of such situations, insulating materials are used.

Types of soundproofing materials

We should start with the fact that noise is divided into separate groups:

1. Structural – caused by vibration due to the operation of various equipment (from household equipment in the house to construction equipment on the street), vehicles, elevators, etc.
2. Percussion - can be caused by stomping, moving interior items.
3. Airborne – conversations, television and radio sounds.

In building acoustics, there are three main types of sound protection from the noise discussed above:

Soundproofing

Provides protection from noise transmitted through the air (human speech, music, etc.). It works according to one of two principles: reducing the intensity of sound waves as they pass through a dense partition or sound reflection from an obstacle.

Noise insulation

This involves protection from complex sound waves caused by a combination of sounds of different strengths and frequencies. This can be structural, airborne, impact, etc. noise.

Sound absorption

Relevant for soft structures, it uses the method of converting sound energy into thermal energy.

In order to correctly select the appropriate soundproofing material, you should take into account what types of noise the protective barrier is “built” against.

Let's conduct a small comparative study of products from well-known manufacturers recommended for residential premises (the group under consideration included only sound insulators effective in the range of 100-3000 Hz).

Review of sound-absorbing and sound-insulating materials

Membrane sound insulators are applicable to any surface, have elasticity, small thickness and increased efficiency in noise absorption. The most popular brands in Russia are Tecsound and Zvukoizol.

Tecsound

This company is a subsidiary of the Spanish company Texsa, which appeared back in 1954. Under the Texound brand, polymer-mineral membranes are produced - elastic, thin, and available in the form of rolls.

The basis of the material is aragonite with the addition of elastomers. It is relevant in frame and frameless systems and can increase the sound insulation properties of a structure by 15 dB.

Such indicators can be compared to a thirty-centimeter concrete wall. Tecsound price – from 850 rub. per square.

Five main series of membranes are produced:

1. Tecsound Al – self-adhesive, equipped with aluminum foil.
2. Tecsound SY – synthetic self-adhesive, suitable for partitions, ceilings, facades.
3. Tecsound 35/50/70 – standard, used for sound insulation of floors and roofs.
4. Tecsound FT – synthetic foil universal, with felt coating.
5. Tecsound 100 – sheet.

Advantages include stretchability, environmental safety, temperature resistance and durability.

Soundproofing

Membrane soundproofing materials based on bitumen-polymer components, produced in Russia, appeared back in 2009. At first, only two series were produced - Zvukoizol and Zvukoizol VEM, intended for the construction sector.

The very next year, the range of products expanded significantly due to the production of several more series, which became a good alternative to foreign analogues K-Fonik ST and Tecsound. This:

1. Sound insulation VEM Standard - viscoelastic insulating material,
2. SMK – self-adhesive base,
3. Zvukoizol-M – roll bitumen-polymer membrane sound insulators with a metallized coating.

The price of domestic sound insulators is more than affordable - from 140 rubles. per square. They are characterized by many positive qualities, including versatility, good sound-absorbing properties, and water resistance.

Soundproofing panels, consisting of several layers, quickly became popular for their relative ease of installation and effectiveness. Among them, ZIPS and SoundGuard can be especially highlighted.

ZIPS

ZIPS sandwich panels, depending on the base, have different purposes. They are made from plywood (GVL) or tongue-and-groove gypsum boards combined with fiberglass or basalt slabs.

Construction based on gypsum fiber/plywood is applicable for floors, plasterboard - for ceiling and wall surfaces.

The Zips frameless system was first developed in 1999; now it includes six types of panels for different purposes:

1. ZIPS-MODULE wall for interior walls and partitions in commercial and residential premises. Index Rw – up to 14 dB.
2. ZIPS-FLOOR MODULE – prefabricated panels for reinforced concrete interfloor floors. They isolate airborne noise in the range from 7 to 9 decibels and shock noise up to 38 dB.
3. ZIPS-Vector for wall and ceiling bases, operating range up to 125 Hz, Rw index up to 11 dB.
4. ZIPS-Paul Vector - provide comprehensive sound insulation of reinforced concrete interfloor ceilings, reduce airborne noise in the range from 6 to 8 dB, impact noise - by 32.
5. ZIPS-CINEMA – additional protection with an Rw index of 16-18 dB. It is used for ceilings and walls in rooms with a high degree of outgoing sound.
6. ZIPS-III-ULTRA – additional protection of ceiling and wall surfaces from airborne noise. Operating range 100 Hz, Rw – 11 dB.

The price of ZIPS panels starts from 1,600 rubles, but this cost is fully justified by their efficiency, low degree of thermal conductivity (that is, the panels also partially serve as a heat insulator), and durability (from 10 years).

SoundGuard

Saungard panels are the “brainchild” of a German-Russian enterprise, which appeared back in 2010 on shares with the Volma company and are characterized by increased efficiency. The panel includes:

• GKL Volma for finishing cladding,
• SoundGuard profiled panel (multi-layer board made of corrugated cardboard, cardboard and mineral quartz filler),
• Frame profile.

Two years later, the SoundGuard TM was registered, after which the production of different types of soundproofing panels began:

1. SoundGuard Ecozvukoizol is a 13 mm soundproofing elastic panel consisting of seven layers with an Rw of 40 decibels.
2. SoundGuard EcoZvukoIzol Fireproof G1, with a thickness of 13 mm and a sound insulation index of up to 42 dB.
3. SoundGuard Slim, 11 mm, seven layers, reducing noise by 36 dB.
4. SoundGuard Standard, 12 mm thick, is characterized by compressive strength and an Rw index of 37 dB.
5. SoundGuardPremium, Rw equal to 44 dB, patented soundproofing material for shades, floors, partitions.

SignGard panels are certified according to all Russian standards, fireproof, easy to install, have low thermal conductivity, price from 810 rubles/sq.m. m.

Mineral wool soundproofing materials also do not lose their popularity, especially in combination with innovative developments. The brands Shumanet and Rock Wool Acoustic Butts have advanced the most in the production of sound protection based on mineral wool.

Schumanet

Shumanet mineral wool boards are produced by the same manufacturer as the ZIPS, Shumostop, Soundlux, Soundline, Vibrosil, Vibroflex panels, namely Acoustic Group LLC.

The Shumanet series of soundproofing materials is designed directly for frame wall and ceiling systems using various types of cladding - gypsum fiber, plasterboard, particle board, plywood. The series includes:

1. Shumanet-SK are fiberglass plates, covered on one side with fiberglass, which prevents the glass fibers from falling off. Relevant when installing acoustic panels such as Knauf-Soundline, Soundboard, etc., they have a sound absorption value of about 0.8 units.
2. Shumanet-Eco - water-repellent boards based on staple fiberglass and acrylic binder. Sound absorption coefficient – ​​0.85 units.
3. Shumanet-BM - basalt slabs with a high sound absorption rate - 0.95 units.

To isolate impact noise in floor structures, a system of combined slabs called Shumostop and bitumen-polymer gaskets Schumanet-100 is produced.

The average price of Schumanet slabs is from 190 rubles per square. They are distinguished by their durability (working life from 10 years), ease of installation, meet the requirements of GOST, and are certified according to the standards of the Russian Federation.

RockWool Acoustic Butts

Multifunctional basalt slabs are produced at almost 30 factories; this is the development of a transnational group of companies that opened its first branch in Russia back in 1999.

Rockwool Acoustic Butts stone wool slabs are practically universal, applicable in interior, exterior and roof cladding in residential and industrial construction.

There are several main series of Acoustic mineral wool slabs:

1. RockWool Floor Butts are rigid, vapor-permeable boards for floor structures with expectedly high loads.
2. RockWool Floor Butts are water-repellent (hydrophobic) for public, commercial and residential premises.
3. RockWool Floor Butts I - gabbro-basalt slab materials for industrial premises.
4. Rockwool Acoustic Butts Pro - ultra-thin slabs.
5. Acoustic Butts standard type.

Rockwool Acoustic Butts products have a lot of advantages, and the price of the slabs is quite affordable - from 120 rubles per square meter.

8087

Low-frequency absorbers Bekeshi Shield and Bascleaner for correcting the acoustics of the listening room

One of the design options for a bekeshi shield measuring 4x2 m

Frame of low-frequency sound absorber "Bekeshi Shield"

Dependence of the resonant frequency of the Baskliner low-frequency absorber on the length and diameter of the pipe
Installation of low-frequency absorbers "Baskliner" in the corners of the recording studio
"Baskliner" device and stepped resonant ceiling
Angular low-frequency absorbers "bascleaner"

Sound-absorbing structures "bascleaner" for different frequencies

The recording studio is acoustically treated with low-frequency absorbers "Baskliner"

Low Frequency Problems

One of the main acoustic problems when creating home theater rooms or listening rooms is low-frequency resonances that cannot be eliminated by any sound-absorbing materials. Rooms for music and watching films are mostly rectangular in shape with three pairs of parallel surfaces (4 walls, floor and ceiling). As a result, in most rectangular rooms there are three pronounced resonances precisely at low frequencies. Their frequencies are related to the distance between the walls, and the larger the room, the lower they are. To the main resonances, multiples of their frequencies are added - higher harmonics. This is the kind of low-frequency “bouquet” you get in a rectangular room, proudly called the “home theater room.” This “bouquet” is expressed in a sharp increase in certain frequencies when walking around the hall, the presence in certain places of “buzz” and dips in the low frequencies that cannot be corrected even by a powerful subwoofer. There are several ways to get rid of these phenomena, and this is not traditionally practiced soundproofing of walls:

• The radical method is to move away from the rectangular shape of the room and flat ceiling, following the example of the listening rooms of a recording studio. Rarely implemented because home cinema halls are built in apartments and cottages, where most rooms have a flat floor, ceiling and are located at 90 degrees. walls. If an attic with a gable or pitched roof is allocated for a home cinema room, it is better for acoustics;
• The “4 subwoofers” method is based on the fact that 2 additional subwoofers are installed at the rear wall, connected in antiphase to the two main ones located near the screen. As a result, low frequencies reaching these two subwoofers are absorbed and the effect of the absence of a back wall (hole effect) occurs;
• A compromise method in terms of cost compared to the previous two is the use of sound-absorbing materials and structures specifically for low frequencies. There are several such methods used in critical areas of listening rooms and halls, where a smooth frequency response at low frequencies is especially important. These methods are based on resonance.

Let's talk about resonant absorption methods. There are separate articles about the non-rectangular shape of the room and “4 subwoofers”, which can be found using the links at the end of the page.

The resonant method of absorbing low frequencies is fundamentally different from soundproofing walls with sound-absorbing materials. It is quite simple to implement, inexpensive and is often used when creating recording studios or similar premises.

When resonance is excited by sound waves in any flat surface (membrane), this surface begins to vibrate and absorb the energy of sound waves precisely at the resonance frequency. If the mechanical vibrations of the membrane are converted into heat, then the sound pressure at the resonance frequency will decrease. The flat surface together with the frame represents an oscillatory system, and a layer of sound-absorbing material acts as a converter of the energy of mechanical vibrations into heat.

The level of attenuation of sound wave energy does not depend on the thickness of the layer of sound-absorbing material, but on the quality factor of the oscillating system. The higher it is, the greater the amplitude of membrane oscillations and the stronger the selection of energy from sound waves at the resonant frequency. True, with a high quality factor, the width of the absorbed frequency range suffers. High-Q systems are narrow-band, although they provide maximum absorption of a certain frequency.

Bekeshi Shields

G. Bekeshi was the first to use tandem structures made of a membrane and a layer of sound-absorbing material, and accordingly, all resonant systems designed to absorb low frequencies are traditionally named after him.

The so-called “Bekeshi Shields” are wooden frames of quite impressive dimensions, covered on one side with a membrane made of tightly stretched aircraft fabric, oilcloth or thin fiberboard, hardboard, etc. The frame is mounted on the wall at the antinode of low frequencies. There should be a distance of about 10-20 cm between the wall and the membrane. Sound-absorbing material in the form of a mineral wool slab 50-100 mm thick is installed in this gap. I repeat once again - sound-absorbing material is not soundproofing of walls, but a converter of mechanical energy of membrane vibrations into heat.

The Bekeshi shield has pronounced resonant properties. Its resonance frequency depends on the physical size, the thickness of the membrane, the material used for the membrane and the tension force. The resonance frequency of the oscillatory system also depends on the weight of the membrane (the ratio of mass to unit area) and the elasticity of the air volume between the membrane and the wall. If the frequency of the sound wave incident on the membrane is close (or a multiple of it) to the resonant frequency of the membrane, oscillations are excited in it. The energy of sound waves is converted into mechanical vibrations of the membrane, which in turn are converted into heat by a layer of sound-absorbing material.

The resonant frequency at which the absorption of sound wave energy is maximum can be made quite low. Bekeshi shields work well at low frequencies.

The significant absorption of low-frequency vibration energy observed in large halls decorated with wooden panels is explained precisely by their resonant properties. The role of active resistance here is played not by the layer of sound-absorbing material between the wall and the panels, but by the internal friction that occurs when the panels are deformed.

Practical application of Bekeshi shields

To improve the acoustics of a room and “dosage” the first reflections, it is Bekesy Shields that are used. These wooden structures, which are quite large in area, absorb well the energy of sound waves not only of low frequencies (at one resonant frequency), but also, fortunately, of medium and high frequencies.

As a rule, the “Bekeshi Shield” is a wooden frame made of boards 100-120 mm wide, hanging on the wall or built flush into it. Inside the frame there is sound-absorbing material: dense basalt fiber, mineral wool, foam rubber and other similar materials of not very high density (50-100 kg/cub.m.).

The front surface of the “Bekeshi Shield” is covered with a stretched PVC membrane with a density of 270-450 g/m2. The membrane has its own resonant frequency, depending on its physical dimensions, material thickness and tension force. Typically, the self-resonance frequency of the membrane (with design dimensions of 1200x2500 mm) is in the region of 27-42 Hz and has an average quality factor. At the resonant frequency and its multiple frequencies, the Bekeshi Shield membrane has a pronounced peak in the absorption of sound energy.

In addition to low frequencies, mid frequencies are also well damped by a layer of sound-absorbing material located under the membrane. The mid-frequency attenuation coefficient is determined by the depth of the bekeshi shield and the density of the sound-absorbing material.

To absorb high frequencies, a soft outer layer can be glued to the membrane. By using different membrane coatings you can influence the high frequency absorption coefficient.

Thus, the “Bekeshi Shield” is a combined acoustic element for absorbing the first reflections in a fairly wide frequency range, and in fact is a three-band sound absorber. In addition to the preferential absorption of low frequencies, the bekeshi panel affects the level of reverberation in the room and the rate of attenuation of the “fluttering echo”. To a lesser extent, it eliminates room buzzing at low frequencies.

Low-frequency room layout

The most important place in the struggle for high-quality sound is occupied by the problem of bass, which manifests itself in a sharp unevenness in the level of low frequencies in the listening room. The unevenness of the bass range is heard by the bulging of individual frequencies, the frantic “buzz” of the subwoofer, or dips when the “swallowing” of individual notes and low-frequency sounds is clearly felt.

Standard methods for correcting deficiencies in room acoustics using equalizers included in modern home theater receivers, which are automatically adjusted, help little. Removing the protrusion and dips of certain frequencies with an equalizer is akin to treating symptoms with pills, instead of looking for the causes of the disease in medicine.

The second traditional method of low-frequency correction is to drag the subwoofer around the room in search of the best place and the most even resulting frequency response of the subwoofer/room system, also a half-measure. Here, most likely, you will have to look for a place not only for a subwoofer, but also for two front speakers and, accordingly, for a sofa and a screen...

You can use Helmholtz resonators, which naturally have a low quality factor and, as a consequence, insufficient efficiency at a high price.

To summarize, we can say that there are a lot of methods for correcting low frequencies in a listening room, but it is advisable to approach them not at the end of the renovation, when “curtains”, but during construction, in order to obtain a obviously predictable, high-quality and inexpensive result. The layout of a listening room usually has the following goals:

• Get rid of the influence on the unevenness of low frequencies of the “box” elements of walls and ceilings, which are made from plasterboard and tension surfaces not intended for acoustic purposes. Replacing plasterboard walls with solid bricks, and a plasterboard ceiling with an acoustic one with perforations, changes the situation in bass and midrange dramatically;
• Create conditions for the formation of the most uniform field in the low-frequency range, for which purpose move away from parallel walls and flat ceilings;
• To eliminate “ringing” at high frequencies and “fluttering echoes,” use soft materials to soundproof walls, floors and ceilings.

A strong passion for such methods of acoustic correction (in combination) can lead to the depletion of individual frequencies and, in particular, the bass. There are techniques that allow you not to suppress antinodes in a room with Bekeshi shields, sound-absorbing materials and other acoustic structures, but to enrich the bass and level out the frequency response at low frequencies - architecturally.

Stepped ceiling

If the room has sufficient headroom, you can create a stepped ceiling with a specially calculated height difference and the area of ​​the “steps”. Steps on the ceiling can be built with such a step that the resonant frequency between each step and the floor differs from the neighboring one by 5-8 Hz. Thus, we obtain a “comb” of resonant antinodes, dividing one resonant frequency of large amplitude (in the case of a single ceiling) into 8-14 evenly distributed over the range. As a result, we equalize the frequency response of the room and enrich the sound of low frequencies with a uniform series of local resonances.

The method is effective, but requires correct calculation and decent architectural work. By the way, steps can be hidden with an acoustically transparent stretch ceiling, and approximately the same effect is obtained when steps are installed not on the ceiling, but on the walls. "Aerobatics" is to adjust parallel planes in accordance with curves of equal volume. Then, in a room without the use of sound-absorbing materials, you can get even and powerful bass.

This is a new series of posts dedicated to acoustic systems. Due to the fact that the topic is extremely broad, we decided to create a series of articles reflecting the selection criteria when purchasing speakers. This post is dedicated to the acoustic properties of cabinet materials and acoustic design. The post will be especially useful for those who are faced with choosing speakers, and will also provide information for people who want to create their own speakers in the process of their DIY experiments.

There is an opinion that one of the decisive factors affecting the sound of speakers is the material of the housing. PULT experts believe that the importance of this factor is often exaggerated, however, it is truly important and cannot be written off. An equally important factor (among many others) that determines the sound of speakers is the acoustic design.

Material: from plastic to granite and glass

Plastic - cheap, cheerful, but resonates

Plastic is often used in the production of budget speakers. The plastic body is lightweight, significantly expands the possibilities of designers; thanks to casting, almost any shape can be realized. Different types of plastics differ greatly in their acoustic properties. In the production of high-quality home acoustics, plastic is not very popular, but it is in demand for professional samples, where low weight and mobility of the device are important.

(for most plastics the sound absorption coefficient ranges from 0.02 - 0.03 at 125 Hz to 0.05 - 0.06 at 4 kHz)

Tree - from felling to golden ears

Due to its good absorption properties, wood is considered one of the best materials for making speakers.

(the sound absorption coefficient of wood, depending on the species, ranges from 0.15 – 0.17 at 125 Hz to 0.09 at 4 kHz)

Solid wood and veneer are used relatively rarely for the production of speakers and, as a rule, are in demand in the HI-End segment. Wooden speakers are gradually disappearing from the market due to low manufacturability, instability of the material and prohibitively high cost.

It is interesting that in order to create truly high-quality speakers of this type that meet the requirements of the most sophisticated listeners, technologists must select material at the cutting stage, as in the production of acoustic musical instruments. The latter is related to the properties of wood, where everything is important, from the area where the tree grew, to the humidity level of the room where it was stored, the temperature and duration of drying et cetera. The latter circumstance makes DIY development difficult; in the absence of special knowledge, an amateur creating a wooden speaker is doomed to act by trial and error.

Manufacturers of such acoustics do not report how the situation really is and whether the described conditions are met, and accordingly, any wooden system requires careful listening before purchasing. With a high degree of probability, two speakers of the same model from the same breed will sound slightly different, which is especially important for some discerning listeners with golden ears with big money.

Columns from an array of valuable rocks are available in units, their cost is astronomical. Everything yours truly has heard sounds excellent. However, in my subjectively pragmatic opinion, it is disproportionate to the cost. Sometimes, well-designed enclosures made of plywood and MDF have no less musicality, but for many audiophiles “not wood” = “not true hi-end”, and for some, “not wood” simply does not allow the status or spoils the interior design.

I believe that one of the best wooden systems in our catalog is this:
Floor-standing acoustics Sonus Faber Stradivari Homage graphite (price appropriate)

Plywood is almost a tree if it hasn't flown over Beijing

Plywood, used for the production of acoustic enclosures, has from 10 to 14 layers and is almost as good as wood in terms of acoustic properties, in particular in sound absorption, while being somewhat cheaper than wood, more technologically advanced in processing, lighter than chipboard and MDF. Multilayer plywood dampens unwanted vibrations well due to the structure of the material.

(sound absorption coefficient of 12-layer plywood ranges from 0.1–0.2 at 125 Hz to 0.07 at 4 kHz)

Like wood, plywood is used in quite expensive and sometimes luxury piece products. The cost of plywood speakers is not much lower than those made from solid wood, and are quite comparable in quality.

In some cases, cases declared by the manufacturer as “plywood” are made of chipboard and MDF. Therefore, low prices for speakers with plywood or wooden casings should alert you. A number of small Asian manufacturers, which change names regularly and sell mostly online, create composite cabinets that include a few small but noticeable plywood (wood) elements, with the bulk made from chipboard.

Among the speakers made from plywood, I can especially highlight this one: Yamaha NS-5000 bookshelf speakers

Chipboard – thickness, density, humidity

Chipboard is comparable in cost to plastic, but does not have a number of disadvantages that are inherent in plastic cases. The most significant problem of chipboard is low strength, with a fairly high mass of material.

Sound absorption in chipboard is non-uniform and in some cases low- and mid-frequency resonances may occur, although the likelihood of their occurrence is lower than in plastic. Plates with a thickness of more than 16 mm, which reach the required density, can effectively dampen resonances. It should be noted that, as in the case of plastic, the properties of a particular chipboard are of great importance. It is important to take into account the density and humidity of the material, since different chipboards differ in these parameters. Thick, dense chipboards are often used to create studio monitors, which indicates the demand for the material in the production of professional equipment.

On a note, for comrades from the DIY fraternity, chipboard with a density of at least 650 - 820 kg/m³ (with a board thickness of 16 - 18 mm) and a humidity of no more than 6-7% is well suited for creating speakers. Failure to comply with these conditions will significantly affect the sound quality and reliability of the speakers.

Among worthy chipboard options for home speakers, our experts highlight: Cerwin-Vega SL-5M

MDF: from furniture to acoustics

Today, MDF (Medium Density Fiberboard) is used everywhere, among other things, MDF is one of the most common modern materials for the production of acoustics.

The reason for the popularity of MDF was the physical properties of the material, namely:

• Density 700 - 800 kg/m³
• Sound absorption coefficient 0.15 at 125 Hz – 0.09 at 4 kHz
• Humidity 1-3%
• Mechanical strength and wear resistance

The material is cheap to produce, has acoustic properties comparable to those of wood, while the resistance of the boards to mechanical damage is somewhat higher. MDF has sufficient acoustic rigidity of the speaker cabinet, and sound absorption meets the parameters necessary for creating HI-FI acoustics.
Visual difference between MDF and chipboard

There are a lot of wonderful systems among MDF acoustics; in my opinion, the optimal ones in terms of price/quality ratio are the following:

→ Yamaha NS-BP182 piano black - bookshelf

→ Focal Chorus 726 - floor-standing

Aluminum alloys - design and precise calculations

The most common metal in the production of speakers is aluminum, as well as alloys based on it. Some authors and experts believe that the aluminum housing reduces resonances and also improves the transmission of high frequencies. The sound absorption coefficient of aluminum alloys is not high, and is about 0.05, which, however, is significantly better than that of steel. To reduce body vibration, increase sound absorption and prevent harmful resonances, manufacturers use sandwich panels, where a layer of high molecular weight polyethylene resins or other low-density materials, such as viscoelastic, is placed between 2 aluminum sheets.

In the case of budget aluminum speakers, manufacturers often rely on design at the expense of sound: as a result, the acoustic characteristics leave much to be desired. Sometimes users of such acoustics complain of a harsh, distorted sound caused by insufficient sound absorption of the housing. Due to the fact that waves are well reflected and poorly absorbed, precise calculation of the housing design, selection of emitters, filters used, as well as the quality of connections of individual parts become very important in metal acoustics.

Among decent-sounding aluminum speakers, I was especially impressed by the sound:

→ Canton CD 310 white high gloss (impressive price, but not prohibitive)

Stone – granite slabs at the price of gold bars

Stone is one of the most expensive materials for the production of acoustic enclosures. Impeccable reflection and the practical impossibility of the appearance of vibrational resonances make these materials in demand among particularly demanding listeners.

Most rocks have a stable sound absorption coefficient, which, for example, for granite is 0.130 for the entire spectrum of sound frequencies, and for limestone 0.264. Manufacturers especially value porous stones, which have higher sound absorption.

Using stone slabs to make DIY acoustics is almost impossible, since it requires not only remarkable knowledge in acoustics and stone processing, but also extremely expensive equipment (no one produces home-made 3-D stone milling machines yet).

For the production of serial speakers, rocks such as granite, marble, slate, limestone, and basalt are used. These rocks have similar acoustic properties, and with appropriate processing they become real works of art. Stone enclosures are often used to create landscape acoustics; in such cases, a cavity is created in the raw stone to accommodate the emitter, in which fastening elements are installed (usually made to order).

The stone has 2 main problems: cost and weight. The price of a stone speaker may be higher than any other with similar characteristics. The weight of some samples of floor systems can reach 40 kg or more.

Glass transparency and sound quality

An original solution is to create speakers from glass. So far, only two companies, Waterfall and SONY, have seriously succeeded in this matter. The material is interesting from a design point of view; acoustically glass creates certain problems, mainly in the form of resonances, which the above-mentioned companies have learned to solve; there are even reference options.

The prices for the transparent miracle can also hardly be called affordable; the latter is associated with low manufacturability and high production costs.

Of the glass samples that were impressive with sound, I can recommend: Waterfall Victoria Evo

Acoustic design - boxes, tubes and horns

Acoustic design is no less important for accurate sound transmission in speakers. I will talk about the most common types (it is natural that certain types can be combined depending on the specific model, for example, the bass-reflex part of the speaker is responsible for the low and mid-frequency range, and a horn is built for high frequencies).

Bass reflex - the main thing is the length of the pipe

A bass reflex is one of the most common types of acoustic design. This method allows, with the correct calculation of the length of the pipe, the cross-section of the hole and the volume of the housing, to obtain high efficiency, an optimal frequency ratio, and amplify low frequencies. The essence of the phase inverter principle is that on the back of the body there is a hole with a pipe, which allows you to create low-frequency oscillations in phase with the waves created by the front side of the diffuser. Most often, the bass reflex type is used when creating 2.0 and 4.0 systems.

To make calculations easier when creating your own speaker, it is convenient to use special calculators; one of the convenient ones is provided at the link.

In the HI-END philosophy, there are extremely radical, uncompromising judgments about bass reflex systems; I present one of them without comment:

“Enemy No. 1 is, of course, nonlinear amplification elements in the sound path (then everyone, to the best of their education, understands which elements are more linear and which are less). Enemy No. 2 is the bass reflex. the bass reflex is designed to show off, it should allow a small cheap speaker to record 50... 40... 30 in the passport, and what a trifle even 20 Hz at a level of -3 dB! But the lower frequency range of the bass reflex ceases to be relevant to music; more precisely, the bass reflex itself is a pipe singing its own melody.”

Closed box - a coffin for extra low

The classic option for many manufacturers is a regular closed box with speaker diffusers brought to the surface. This type of acoustics is quite simple to calculate, but the efficiency of such devices is not great. Also, the boxes are not recommended for lovers of characteristically pronounced lows, since in a closed system without additional elements that can enhance the lows (bass reflex, resonator), the frequency spectrum from 20 to 350 Hz is poorly expressed.

Many music lovers prefer the closed type, since it is characterized by a relatively flat frequency response and realistic “honest” transmission of the reproduced musical material. Most studio monitors are created in this acoustic design.

Band-Pass (closed resonator box) – the main thing is not to buzz

Open body - no extra walls

A relatively rare type of acoustic design today, in which the rear wall of the housing is repeatedly perforated or completely absent. This type of design is used to reduce the number of housing elements that affect the frequency response of the speakers.

In an open box, the front wall has the most significant influence on the sound, which reduces the likelihood of distortion introduced by other parts of the case. The contribution of the side walls (if any are present in the structure), given their small width, is minimal and amounts to no more than 1-2 dB.

Horn design - problematic loudness champions

Horn acoustic design is more often used in combination with other types (in particular for the design of high-frequency emitters), however, there are also original 100% horn designs.

The main advantage of horn speakers is their high volume when combined with sensitive speakers.

Most experts, not without reason, are skeptical about horn acoustics, for several reasons:

• Structural and technological complexity, and accordingly, high requirements for assembly
• It is almost impossible to create a horn speaker with a uniform frequency response (with the exception of devices costing 10 kilobucks and above)
• Due to the fact that the horn is not a resonating system, it is impossible to correct the frequency response (a minus for DIYers who intend to copy a Hi-end horn)
• Due to the peculiarities of the waveform of horn acoustics, the sound volume is quite low
• Overwhelmingly relatively low dynamic range
• It produces a large number of characteristic overtones (considered a virtue by some audiophiles).

Horn systems have become the most popular among audiophiles in search of “divine” sound. The tendentious approach allowed the archaic horn design to get a second life, and modern manufacturers were able to find original solutions (effective, but extremely expensive) to common horn problems.

That's all for now. To be continued, as usual, but the “autopsy” will definitely show... I’ll announce for the future: emitters, power/sensitivity/room volume.

habr.com

The best soundproofing material, soundproofing ratings

Soundproofing of residential premises is becoming more and more relevant every year. And every homeowner wants to choose the best soundproofing material to protect against outside noise. Although it is difficult to choose soundproofing products based on the “good or bad” principle, since many of them have a specific purpose and, to one degree or another, fulfill the intended purpose.

The best soundproofing material, top six ranking

As a rule, sound insulation is a complex multilayer structure, including dense layers that reflect sound waves and soft layers that absorb extraneous sounds. In this regard, neither mineral wool, nor membrane, nor panel materials should be used as independent sound insulation.

At the same time, it is a mistake to assume that heat insulators (cork, PPS, PPE, etc.) are capable of fully fulfilling the role of noise protection. They are not able to stop creating a barrier against the penetration of structural noise. Even worse, if sheets of polyurethane or polystyrene foam are glued to the wall under the plaster, then such a design will increase the resonance of incoming noise.

Review of the best soundproofing materials

Rock Wool Acoustic Butts

In first place we can put Rockwool Acoustic Butts, a group of companies that have been producing basalt fiber slabs for the eighth decade. Stone wool, pressed into panels, has found its use in both residential and industrial construction as a heat and sound insulator.

Advantages of Rockwool Acoustic Butts:

• High sound absorption class (A/B depending on thickness), excellent sound absorption ability: air vibrations up to 60 dB, shock – from 38.
• Low thermal conductivity and complete fire safety.
• Vapor permeability, moisture resistance, biostability, durability.
• Certification according to Russian Federation and EU standards.
• Easy to install.

Flaws:

There is a risk of purchasing a fake.

High cost, largely due to the need to use additional components and waste accounting.

Soundproofing

These are membrane-type bitumen-polymer soundproofing materials based on modified resins, which have sound, heat and waterproofing qualities. Applicable for walls, ceilings and floors, including “warm” ones using a floating system. Included in category G1 - low-flammable.

Positive properties:

• Versatility, durability, affordable price.
• Water, bio and temperature resistance (-40/+80°C).
• Low degree of thermal conductivity in accordance with SNiP 23-02-2003.
• Sound protection for airborne noise up to 28 dB, for shock – up to 23.

Negative:

• A small dealer network in the Russian Federation.
• The elements have considerable weight, and therefore they cannot be called the best option for weak load-bearing foundations.
• We only allow one installation method – adhesive.

Tecsound

The company produces polymer-mineral membrane soundproofing materials. These are flexible, elastic roll products, very dense, which is why they are classified as heavy. The basis is aragonite and elastomers. Belongs to classes G1 and D2 - low flammability, with an average degree of smoke formation.

Advantages:

• Resistance to rotting, moisture and temperature resistance (properties do not change even at t°-20), durability.
• Versatility due to the property of stretching.
• Certification according to Russian and European standards.
• Environmental safety due to the absence of phenol-containing substances.
• Reduction of airborne noise up to 28 dB.

Flaws:

• Possibility of installation - only adhesive.
• Not applicable as an independent material for sound insulation.

The cost is above average.

Schumanet

Mineral wool boards of the Schumanet series are designed for wall and ceiling frame soundproofing systems for subsequent finishing with facing materials (plywood, plasterboard or fiber sheets, chipboard).

data-ad-client=”ca-pub-4950834718490994″
data-ad-slot=”8296353613″>

• Resistance to humidity, formation of mold and mildew, durability.
• Excellent vapor permeability and minimal thermal conductivity.
• Complete fire safety and non-flammability - classes KM0 and NG.
• Compliance with high sound absorption classes - A/B at any frequency, reduction of structural and airborne noise waves from 35 dB.
• Russian Federation certification.
• Easy to install due to its elastic properties.

Flaws:

An increased degree of phenol emission (slightly exceeds the permissible level), that is, environmental friendliness is in question.

High cost due to the need to purchase many additional items. elements, the need to strictly follow the installation instructions.

ZIPS panels

The panel system from the manufacturer Acoustic Group appeared at the very end of the last century. This is a multi-layer structure, the composition of which varies depending on its purpose. For ceiling and wall surfaces, tongue-and-groove plasterboard sheets are used as a base, and for floor surfaces, gypsum fiber sheets are used. They are supplemented with fiberglass or basalt slabs. To a large extent, vibration units made of polymer and silicone prevent the transmission of vibration and noise waves. Flammability degree G1 (low flammability).

Advantages:

• Durability, efficiency and biostability.
• Low thermal conductivity.
• The absence of inter-plate gaps during installation is ensured by the tongue-and-groove type of connection.
• There is no need to use adapters when attaching plates.
• Compliance with GOST requirements.

Flaws:

When mounted on a wall, the slabs can resonate by 2-3 dB with incoming and outgoing low-frequency noise up to 100 Hz.

During the installation process, many components are required, which significantly increases the final cost of installation.

SoundGuard Plates

A fairly effective product, attractive at an affordable price, produced by an alliance of experienced manufacturers who have been known on the Russian market for several years. Prefabricated noise protection structure includes:

• Drywall Volma,
• SoundGuard profiled board (consists of plasterboard with mineral-quartz filler and a cardboard cellulose panel),
• Frame profile.

According to the degree of flammability, they belong to group G2 (moderately flammable), toxicity T1 (low). The advantages of SaunGuard panels include:

Compliance with all safety requirements and certification of the Russian Federation.

Versatility - the slabs are suitable for any wall and floor bases.

Minimum thermal conductivity.

Good sound insulation performance (airborne noise - up to 60 dB, shock - up to 36).

Easy installation, the ability to choose the installation method (adhesive, frame, using plastic dowels).

Disadvantages:

• Lack of moisture resistance properties.
• There are few sales representatives in Russia.
• High prices.
• During the cutting process, the mineral filler is shed. This necessitates the need to cover the edges of all slabs with tape or tape.

In addition, if the panels are used as an independent sound insulator, then the degree of interference with impact and airborne noise does not exceed 7 dB. Like ZIPS, panels can resonate with low-frequency noise.

otdelkadom-surgut.ru

Soundproofing of premises for various purposes – Acoustic Group

Acoustic Group has been bringing peace and quiet to its clients' homes for over 18 years. We produce and sell materials designed to create a comfortable acoustic environment. Our specialization is sound insulation in apartments, offices, and factories, a wide range of vibration insulation tasks, and acoustics of premises for various purposes, including theaters, concert and sports halls, as well as cinema halls. Our acoustic engineers are ready to solve almost any problem:

• Acoustic design;
• Measurements;
• Expertise;
• Consulting;
• Project support.

Our customers are not only corporate clients, but also individuals. Most often they require soundproofing for an apartment. At the same time, we approach each case individually, understanding that universal recipes do not always work. Our task is to achieve the desired result, and not to sell a solution that is convenient for ourselves. Our portfolio includes many different projects, from small apartments and country houses to world-famous concert and theater halls.

Acoustic Group - professional soundproofing and soundproofing of apartments, offices, premises for various purposes with guaranteed results

A lot depends on acoustic parameters: the sound quality of audio equipment, the penetration of street noise or noise from neighbors and, ultimately, the comfort of staying in the room. To create a calm and comfortable atmosphere, our engineers have developed and introduced unique materials into production. Soundproofing solutions from Acoustic Group for floors, walls and ceilings have been time-tested and, nevertheless, are constantly being improved and updated. All Acoustic Group products are certified and meet the most stringent quality standards.

We offer sound insulation solutions for walls and ceilings:

Frameless systems. Modern sound insulation using ZIPS sandwich panels. Effective, high quality, the thinnest of those that actually work. At the same time, it is quickly and easily installed. They provide ADDITIONAL sound insulation for airborne noise at a level of 9-18 dB (depending on the chosen design).

Frame systems. Thicker. However, they are also effective. They are made using the Gyproc Ultrastil metal profile, Vibroflex vibration suspensions, special weighted plasterboard Aku-Line, acoustic plates Shumanet-ECO, SK or BM. Provide reliable protection of premises from external noise.

Sound insulation of the room: floor materials

• Shumanet-100Combi and 100Hydro - under the screed, to comply with impact noise standards (can be used in several layers to enhance the effect).
• Noise stop C2 and K2 - under the screed, for maximum sound insulation in terms of impact and airborne noise.
• Shumoplast - under the screed, for uneven floors.
• Akuflex underlay for finishing coatings to protect neighbors from impact noise.
• Vibrostek-M, Sylomer SR, Shumanet-EKO, SK or BM, Vibrosil - for floor structures on joists.

Soundproofing of premises: materials for walls and ceilings

• ZIPS-III-Ultra, ZIPS Vector, ZIPS Module, ZIPS Cinema - sandwich panels for frameless sound insulation.
• Acoustic triplex Soundline-dB
• Soundproofing panels Soundline-PGP Super for thin partitions
• Special weighted gypsum board Aku-Line
• Vibroflex suspensions and wall mounts
• Acoustic slabs Schumanet EKO, BM, SK

Vibration isolation: materials

• Sylomer SR is a polyurethane elastomer with a wide range of applications.
• Isotop - spring vibration isolators.
• Vibroflex suspensions 1/30 M8 and 4/30 M8.
• Vibroflex SM vibration isolation supports.
• Mastic Vibronet.

Proper acoustics in a room can be achieved by creating decorative and acoustic materials that not only provide aesthetic appeal, but also allow you to adjust the acoustic characteristics.

Advantages of Acoustic Group:

• Impeccable quality. Only proven effectiveness, many years of implementation experience and positive customer reviews.
• Reasonable cost of materials. Sound insulation for an apartment is a rather expensive item in the renovation estimate. However, our price for materials, upon detailed calculation, turns out to be not only justified, but also one of the best on the market.
• Full range of services. We don't just supply materials. Our engineers are ready for comprehensive work on site from the design stage to the moment of commissioning of the facility, carrying out all the necessary acoustic measurements.
• Wide geography. Our products are available throughout Russia, as well as in the CIS countries. You can buy it directly at Acoustic Group sales offices or from the company’s partners. You can directly order soundproofing of your apartment from us in Moscow, Kyiv, Minsk, Almaty and many other cities.

www.acoustic.ru

Acoustic design - Basics of acoustics

The well-known confusion in understanding the principles of formation of the bass section of acoustics is largely due to the information policy of advertising, and often reference publications. There, the potential buyer is first told the size of the speaker, then its power, then the mythical “frequency range” and ends with the winning price.

All? Not so! This is where it all begins. In English, the speaker itself is called driver - drive, and this is very correct. Just as an engine will become a car only by enriching itself with everything that humanity has developed for this, so a speaker will become a loudspeaker only in its inherent acoustic design.

With high-frequency and mid-frequency heads the situation is relatively simple: the high-frequency heads carry their own acoustic design, while the mid-range heads require minimal dimensions.

Bass players are a different matter. Here, almost everything is determined by the choice of acoustic design, and depending on this choice, all the parameters communicated to you will be subject to revision: power, frequency range, and, in a certain sense, price. Because with skillful selection of parameters, you can achieve the sickening sound of the most expensive and thoroughbred bass speaker.

Now it’s time to “announce the entire list.” It's not that long:

The task of any low-frequency acoustic design is solved according to the ancient principle of “divide and conquer”. “Separate” means that the vibrations emitted by one side of the diffuser must be somehow separated from the vibrations created by its opposite side, simultaneously and in antiphase with the first. “Conquer” means that the “extra” sound waves cut off in this way can be dealt with in different ways.

Historically, the first acoustic design was an acoustic screen. It holds the defense, preventing oscillations from one side of the diffuser to the other and preventing them from mutually destroying up to frequencies at which the shortest distance between the front and back sides of the diffuser becomes comparable to the half-wavelength of the emitted frequency. And below this frequency, the acoustic screen “becomes completely incapable” and allows antiphase waves to cancel each other out as they please. To suppress an acoustic short circuit at a frequency of, say, 50 Hz, the shield must have a size of 3 meters by 3. Therefore, this type of acoustic design has long lost its practical significance, although it is still used as a reference when measuring speaker parameters.

Structurally, the simplest acoustic design of those practically used is closed box (sealed or closed in foreign terminology). Here, unnecessary vibrations are dealt with decisively and abruptly: locked in a confined space behind the diffuser, they will sooner or later fade away and turn into heat. The amount of this heat is tiny, but in the world of acoustics everything is in the nature of small disturbances, so how this thermodynamic exchange occurs is not indifferent to the characteristics of the acoustic system. If the sound waves inside the loudspeaker body are allowed to dangle unattended, a significant part of the energy will be dissipated in the volume of air contained inside the case, it will heat up, albeit slightly, and the elasticity of the air volume will change, and in the direction of increasing rigidity. To prevent this from happening, the internal volume is filled with sound-absorbing material. While absorbing sound, this material (usually wool, natural, synthetic, glass or mineral) also absorbs heat. Due to the significantly greater heat capacity of sound-absorbing fibers than air, the temperature increase becomes much smaller and it “seems” to the speaker that there is a significantly larger volume behind it than in reality. In practice, in this way it is possible to achieve an increase in the “acoustic” volume compared to the geometric one by 15 - 20%. This, and not at all the absorption of standing waves, as many believe, is the main point of introducing sound-absorbing material into closed loudspeakers.

A variation of this (and not the previous one, as is often believed) type of acoustic design is the so-called “ endless screen" In English-language sources, this type of design is called infinite baffle or free-air. All the names given are equally misleading. We are all adults here and we understand that in practice there cannot be an endless screen. In fact, an infinite screen is considered to be a closed box with a volume so large that the elasticity of the air enclosed inside it is much less than the elasticity of the diffuser suspension, so that the speaker simply does not notice this elasticity and the characteristics of the speaker system are determined only by the parameters of the head. Where the boundary lies, starting from which the volume of the box becomes seemingly infinite, depends on the parameters of the speaker. However, when solving practical problems, this volume always turns out to be the internal volume of the trunk, which, even in a small car, will give the reaction of an “infinitely large” volume even for a large speaker. Another thing is that not every speaker will work well in such a design, but we will discuss this separately when we talk about choosing a speaker for an acoustic design (or vice versa).

Despite all the (by the way, apparent) simplicity of a closed box as an acoustic design for the low-frequency section of car acoustics, this solution has many advantages that are absent in other, more sophisticated designs.

Firstly, the simplicity (or simplicity) of calculating characteristics. A closed box has only one parameter - internal volume. You can choose the right one if you try! The margin for errors here is reduced to a minimum.

Secondly, over the entire frequency range, down to zero, the vibrations of the diffuser are restrained by the elastic reaction of the air volume inside the box. This significantly reduces the likelihood of speaker overload and mechanical damage. I don’t know how comforting this sounds, but for avid bass lovers, the speakers in closed boxes sometimes burn, but almost never “spit out”.

Thirdly, only the closed box is a second-order acoustic filter, that is, it has a drop in frequency response below the resonance frequency of the head-box system with a slope of 12 dB/oct. Namely, the frequency response of the interior volume of a car, below a certain frequency, has precisely this steepness, only in the opposite sign. If you guess, calculate or measure (whatever happens), it becomes possible to obtain a perfectly horizontal frequency response at lower frequencies.

Fourthly, with the right choice of head parameters and volume for it, a closed box has no equal in the field of impulse characteristics, which largely determine the subjective perception of bass notes.

The natural question now is - what’s the catch? If everything is so good, why are all other types of acoustic design needed?

There is only one catch. Efficiency For a closed box it is the smallest compared to any other type of acoustic design. Moreover, the smaller we manage to make the volume of the box, while maintaining the same operating frequency range, the less effective it will be. There is no more insatiable creature in terms of power input than a closed box of small volume, which is why the speakers in them, as was said, although they do not spit out, they often burn...

The next most common type of acoustic design is bass reflex(ported, vented, bass-reflex), more humane in relation to the radiation from the rear side of the diffuser. In a bass reflex, part of the energy that is “put against the wall” in a closed box is used for peaceful purposes. To do this, the internal volume of the box communicates with the surrounding space through a tunnel containing a certain mass of air. The size of this mass is chosen in such a way that, in combination with the elasticity of the air inside the box, it creates a second oscillatory system that receives energy from the back side of the diffuser and radiates it where needed and in phase with the radiation of the diffuser. This effect is achieved in a not very wide frequency range, from one to two octaves, but the efficiency is within its limits. increases significantly, according to the principle “no waste - there are unused resources.” In addition to higher efficiency The bass reflex has another important advantage - near the tuning frequency, the amplitude of the diffuser oscillations significantly decreases. This may at first glance seem like a paradox - how the presence of a hefty hole in the loudspeaker housing can restrain the movement of the cone, but nevertheless it is a fact of life. In its operating range, the bass reflex creates completely greenhouse conditions for the speaker, and exactly at the tuning frequency the oscillation amplitude is minimal, and most of the sound is emitted by the tunnel. The permissible input power is maximum here, and the distortion introduced by the speaker is, on the contrary, minimal. Above the tuning frequency, the tunnel becomes less and less “transparent” to sound vibrations, due to the inertia of the air mass contained inside it, and the loudspeaker acts as if it were closed. Below the tuning frequency, the opposite happens: the inertia of the speaker gradually disappears and at the lowest frequencies the speaker operates practically without load, that is, as if it had been removed from the housing. The amplitude of oscillations quickly increases, and with it the risk of spitting out the diffuser or damaging the voice coil from hitting the magnetic system. In general, if you do not take precautions, going for a new speaker becomes a real prospect.

A means of protecting against such troubles, in addition to being careful in choosing the volume level, is the use of infra-low-pass filters. By cutting off the part of the spectrum where there is still no useful signal (below 25 - 30 Hz), such filters prevent the diffuser from going into disarray at the risk of your own life and your wallet.

Bass reflex significantly more capricious in the selection of parameters and settings, since three parameters are subject to selection for a specific speaker: box volume, cross-section and tunnel length. The tunnel is very often made so that with a ready-made subwoofer it is possible to adjust the length of the tunnel by changing the tuning frequency.

Due to the presence of two interconnected oscillatory systems, the bass reflex is a fourth-order acoustic filter, that is, its frequency response theoretically has a roll-off of 24 dB/oct below the tuning frequency. (Actually, from 18 to 24). It is almost impossible to obtain a horizontal frequency response when installed in a cabin. Depending on the ratio of the size of the cabin (and, therefore, the characteristic frequency from which the rise in the frequency response of the internal acoustics begins) and the tuning frequency of the bass reflex, the total characteristic may have deviations from a delicate hump to crazy Amur waves. The hump, that is, a smooth rise in the frequency response at lower frequencies, is often just what is needed for optimal subjective perception of bass in a noisy space, but sudden changes in amplitude with an unsuccessful choice of parameters have earned the bass reflex, completely undeservedly, the nickname boom-box (“booze”) . To restore justice, we note that the thumping effect can be achieved from a closed box - I’ll explain how next time; and a properly designed bass reflex can produce very clear and musical bass with a reasonable power input.

A type of bass reflex design is passive radiator loudspeaker(or radiator). Foreign terms: passive radiator, drone cone. Here, the creative oscillatory system, which makes it possible to utilize the energy removed from the rear side of the diffuser, is implemented not in the form of a mass of air in the tunnel, but in the form of a second diffuser, not connected to anything, but weighted to the required mass. At the tuning frequency, this diffuser oscillates with the greatest amplitude, and the main one with the smallest. As they move up in frequency, they gradually change roles. Until recently, this type of acoustic design was not used in mobile installations, although it is used quite often in home ones. The reason for the dislike was the unjustified hassle of obtaining a second diffuser (this is usually the same speaker, but without a magnetic system and voice coil) and difficulties in placing two large diffusers where a conventional bass reflex would need to place a diffuser and a small tunnel. However, recently, car subwoofers with passive radiators have appeared - need forced them. The fact is that recently a new generation of speakers with a very large diffuser stroke, designed to work in small volumes, have begun to appear. The volume of air “blown out” by them during operation is very large, and the tunnel would have to be made significant in diameter (otherwise the air speed in the tunnel will increase so much that it will hiss like a steam locomotive). And the combination of a small volume and a large tunnel diameter makes it necessary to choose a longer length for the tunnel. So it turned out that bass reflexes of a conventional design for such heads would be decorated with meter-long pipes. To avoid such unnecessary incidents, we preferred to concentrate the required oscillating mass in a passive radiator with a diffuser stroke the same as that of an active speaker.

The third type of subwoofer, quite often used in auto installations (although less frequently than the previous two) is bandpass loudspeaker. Sometimes the name “balanced-load loudspeaker” () is used. If a closed box and a bass reflex are acoustic high-pass filters, then a band-pass filter, as the name implies, combines high- and low-pass filters.

The simplest bandpass loudspeaker - single 4th order(single reflex). It consists of a closed volume, the so-called. rear chamber and a second one, equipped with a tunnel, like a conventional bass reflex (front chamber). The speaker is installed in the partition between the chambers so that both sides of the diffuser operate in completely or partially closed volumes - hence the term “symmetrical load”.

Of the traditional designs, the bandpass loudspeaker, in any version, is the champion in efficiency. Moreover, efficiency is directly related to bandwidth. The frequency response of a bandpass loudspeaker has the shape of a bell. By selecting the appropriate volumes and frequency tuning of the front chamber, it is possible to build a subwoofer with a wide bandwidth, but limited output, that is, the bell will be low and wide, or it can be with a narrow bandwidth and very high efficiency. in this strip. At the same time, the bell will stretch in height.

Bandpass- a capricious thing to calculate and the most labor-intensive to manufacture. Since the speaker is buried inside the case, it is necessary to go to some lengths to assemble the box so that the presence of a removable panel does not violate the rigidity and tightness of the structure. Coordinating the frequency characteristics of the subwoofer, interior and front speakers is also associated with a well-known headache. The impulse characteristics are also not the best, especially with a wide bandwidth. How is this compensated?

First of all, as stated - the highest efficiency.

Secondly, the fact that all sound is emitted through the tunnel, and the speaker is completely closed. When assembling such a subwoofer, considerable possibilities open up for an installer (or amateur) with imagination. It is enough to find a small place at the junction of the trunk and the passenger compartment, where the mouth of the tunnel can be placed - and the path is open to the most powerful bass. Especially for such installations, JLAudio, for example, produces flexible plastic tunnel sleeves, with which it proposes (and many agree) to connect the subwoofer output to the cabin. Like a vacuum cleaner hose, only thicker and stiffer.

Strip strips are even more effective 6th order loudspeakers with two tunnels. The chambers of such a subwoofer are adjusted at intervals of approximately an octave. A double bandpass provides less distortion in the operating band, since the speaker is loaded with bass reflexes on both sides of the diffuser, with all the advantages of such a load, but has a steeper frequency response decline below the operating band compared to a single bandpass.

An intermediate position is occupied by the so-called quasi-bandpass loudspeaker, also with a sequential setting, where the rear chamber is connected by a tunnel to the front, and the front chamber is connected by another tunnel to the surrounding space.

Three-chamber bandpass loudspeakers are simply alternative structural implementations of conventional bandpass loudspeakers, and are composed of two conventional ones, after which the wall separating them has been removed.

There are three more options for the acoustic design of low-frequency acoustics, which, although they exist, are practically not used. The first of the outsiders - acoustic labyrinth, where “energy removal” from the back of the diffuser occurs through a long pipe, usually folded for compactness, but still increasing the dimensions of the subwoofer to limits that are unacceptable in a mobile installation.

Second - exponential horn, which, in order to obtain a sufficiently low cut-off frequency, must have cyclopean dimensions, which makes its use in the low-frequency link rare, even in stationary systems where there is more space than in a car.

The third type, which has isolated precedents for use, is loudspeaker with aperiodic load in the form of concentrated acoustic resistance ( aperiodic membrane). We used to call it PAS - acoustic absorption panel. The idea is that the load for the diffuser is a nearby semi-permeable barrier, for example, dense fabric or a layer of silica wool sandwiched between perforated panels. Theoretically, such a load is inelastic in nature and, like a shock absorber in a car suspension, absorbs acoustic energy without affecting the resonant frequency of the speaker. But this is theoretical. But in practice, the presence of an air volume between the speaker and the PAS created such a mixture of characteristics and reactions that the results became difficult to predict.

So, from a quick glance at the main types of acoustic design, it is clear that there is no perfection in the world. Any choice will be a compromise. And to make the essence of the compromise clearer, let's end this correspondence meeting as it should be - by summing up the interim results. Let's compare the considered options in terms of the main factors that determine the success of their use in a mobile audio installation.

These factors should include:

Efficiency

The amount of efficiency inherent in a particular type of acoustic design ultimately determines how powerful an amplifier will be needed to achieve the required volume level, and at the same time how difficult the life of the speaker will be.

In the most important frequency range from the point of view of reproducing information in the bass register, 40 - 80 Hz, places will be distributed as follows: narrow-band bandpass loudspeakers are champions in this category, especially double-tunnel 6th order ones. They are followed by a wideband dual-tunnel and a conventional bass reflex. And finally, the ones that are most hungry for power input are a closed box and a wideband single bandpass.

Introduced Distortion

In the lower octave - one and a half musical range (30 - 80 Hz) all types of acoustic design behave decently at low power levels. The bass reflex and bandpass loudspeaker are somewhat better than others, but not by much. But at high power the opponents are stretched along the distance. The best results here should be expected from a dual bandpass loudspeaker. Behind it is a single bandpass and bass reflex. And it completes the circuit - a closed box that produces the greatest distortion at large signal amplitudes.

Impulse characteristics

Accurate reproduction of the fronts of bass instruments is perhaps the main quality for bass acoustics. Low bass efforts are of little use if they are blurred and sluggish. In this regard, a closed box promises the best results (if calculated correctly). The transient characteristics of a bass reflex can be very decent, but still on average will be inferior to a closed design. Single bandpass loudspeakers have good performance, which, however, deteriorates as the bandwidth increases. The worst response to a pulsed signal has a dual bandpass loudspeaker, again, especially a wideband one.

The work of the subwoofer should be, starting from a certain frequency, delegated to the midbass of the front speakers. For a closed box and a bass reflex, this is not a problem and the system designer has a fair amount of freedom in choosing the crossover frequency, since both this frequency and the slope of the rolloff are determined by external circuits. But narrowband bandpasses often have their own frequency rolloff starting from 70-80 Hz, where not all midbass can painlessly pick up a song. At the same time, the requirements for midbass become more complicated, and working with a crossover does not become any easier.

Let’s put all of the above in a table, based on our usual five-point system:

				Bandpass loudspeaker
				single		double
	Closed box	Bass reflex		Narrow band	Wide band	Narrow band	Wide band
Distortion at low power	4	5		5	4	5	4
Distortion at high power	2	4		4	3	5	4
Impulse characteristics	5	4		4	2	3	2
Coordination with front speakers	5	5		2	4	2	4
Overload capacity in the operating range (above 30 Hz)	>	4		5	4	5	4
Overload capacity in the infra-low frequency range below 30 Hz)	5	2		5	5	2	2
Smoothness of the frequency response taking into account the internal acoustics of the car.	5	4		2	3	2	3
Sensitivity to design and manufacturing errors	5	4		2	2	2	2

baseacoustica.ru

Room acoustics - sound absorption - Paroc.ru

Products

Construction insulation

General construction thermal insulation

PAROC eXtra

PAROC eXtra light

PAROC eXtra plus

PAROC eXtra Smart

Thermal insulation of walls

PAROC InWall

PAROC WAB 10t

PAROC WAS 120

PAROC WAS 25t

PAROC WAS 35

PAROC WAS 35t

PAROC WAS 35tb

PAROC WAS 50

PAROC WAS 50t

Windproof insulation

PAROC WPS 1n

PAROC WPS 3n

Thermal insulation of plaster facades

PAROC Fatio

PAROC Linio 10

PAROC Linio 15

PAROC Linio 18

PAROC Linio 20

PAROC Linio 80

Thermal insulation for sandwich panels

PAROC COS 5

PAROC CES 50C

PAROC CES 50CS100

PAROC COS 10

Thermal insulation of flat roofs

PAROC ROB 60

PAROC ROB 80

PAROC ROB 80t

www.paroc.ru

Soundproofing and sound-absorbing materials

What is the difference between sound insulation and sound absorption?

Soundproofing is measured in decibels, a term used when talking about reducing the volume of outgoing/incoming noise.

Sound absorption is assessed by calculating the sound absorption coefficient and is measured from 0 to 1 (the closer to 1, the better). Sound-absorbing materials absorb sound inside the room and dampen it, resulting in the disappearance of echoes.

If you need to get rid of the noise from your neighbors, you need soundproofing materials. If you need the absence of echo in the room, sound-absorbing ones.

How to reduce noise from neighbors above/below/behind the wall? Is it possible to rid them of my noise?

Soundproofing the ceiling is obviously a losing option. The maximum reduction that can be achieved is from 3 to 9 dB. Try to come to an agreement with your neighbors and soundproof the floor for them, then you will achieve a reduction of up to 25-30 dB!

The sound insulation of a wall depends on the type of wall. They are either under construction or already existing (between rooms and apartments). For erected walls, immediately make double, independent frames. The thicker and more multi-layered the wall, the higher the chance of achieving a noise reduction of 50-60 dB in the apartment.

For existing walls, either make a frame filled with soundproofing materials, but be prepared for it to “eat up” 10 cm of space. Or, if space is limited, attach soundproofing panels or roll material directly to the wall.

To soundproof the floor, place materials such as TOPSILENT DUO or FONOSTOP BAR under the screed. If it is not possible to raise the floor under the screed by 10 cm, then lay soundproofing materials under the floor covering. Please note that in this case the noise will decrease by no more than 10-15 dB.

Try to ensure that the screed and flooring do not come into contact with the walls of the premises. The “floating” design provides better sound insulation properties. Conversely, if the soundproofing layer extends a couple of centimeters onto the walls, this will additionally dampen the sound waves.

We made repairs, didn’t think about soundproofing and now we hear noise from our neighbors, how can we fix it?

Unfortunately, you will have to make changes to repairs that have already been made.

If soundproofing of the floor is necessary, remove the laminate (or other finishing coating) and lay the FONOSTOP DUO soundproofing membrane underneath.

If there are walls, then, as mentioned above, the covering needs to be removed, a frame must be made and a material like TOPSILENT BITEX must be glued. Likewise for the ceiling.

What materials should be used to soundproof an apartment? How many of them do you need? How to calculate the required quantity?

Soundproofing an apartment requires an integrated approach. A structure is assembled, a “sandwich” of several materials. The thickness of a high-quality structure is about 7-10 centimeters.

To calculate the required quantity, send the dimensions of the room - length, width and height, the manager will make the calculation and tell you what materials will be needed.

What materials are needed for a recording studio?

For a recording studio, both types of materials are important and needed - soundproofing and sound-absorbing. First of all, high-quality sound in a studio is achieved through the use of sound-absorbing, acoustic panels made of melamine foam or open-cell polyurethane. The cellular structure of the material “quenches” sound vibrations. We recommend using thick panels up to 100 mm, this will ensure sound absorption in a wide range of frequencies. In addition, install “bass traps” up to 200-230 mm thick.

With sound insulation, everything is simple - more layers and it is advisable to use two-layer materials with a lead layer, for example, AKUSTIK METAL SLIK.

Which sound insulation is better?

The best material is the one that solves the problem. The same soundproofing materials manifest themselves differently depending on the volume, type of walls, and ceiling of the room. We recommend that you consult with a specialist before you begin any repairs.

How is soundproofing and sound-absorbing materials installed?

The easiest way is to attach sound-absorbing acoustic panels. Take any type of glue and attach it wherever you need it. The material is light and easily adheres to the surface.

For the installation of soundproofing materials, specially designed adhesives are used - OTTOCOLL P270 (for floors) and FONOCOLL (for walls and ceilings).

Do you deliver materials? Is there pick-up?

Yes, we deliver. Choose a convenient delivery method: pickup from a warehouse in Lyubertsy, delivery by van within the Moscow Ring Road and Moscow region (up to 100 km) or a transport company if you are far from Moscow.

Where can I see prices?

The price list for soundproofing and sound-absorbing materials is in the “Price Lists” section.

www.riwa.ru

Vertical sound-absorbing materials for improved acoustics

To create an optimal sound environment It is necessary to use different types of sound absorbers. A sound-absorbing ceiling significantly reduces the sound pressure level and sound propagation in the room. However, bare walls will create an echo effect.

Vertical sound absorbers reduce echo and improve speech intelligibility so you can hear what people say clearly.

Required number of vertical sound absorbers will depend on the characteristics of the premises itself and the type of activity carried out in it:

In open offices It is important to prevent the spread of speech and noise so that it does not disturb employees.

In schools Students need a supportive learning environment that allows them to hear the teacher and each other well and have the opportunity to think in silence.

In medical institutions patients need peace to rest and recover, and staff also need to be able to communicate.

Read more in the “Acoustic Solutions” section.

Acoustic parameters and their application

Reverberation time (RT) is the most commonly used parameter for calculations and measurements in room acoustics. The Sabin formula or its derivatives are also commonly used. This formula is easy to use, since you only need to know the volume of the room and the amount of sound-absorbing material, calculated through the statistical sound absorption coefficient αp. However, these formulas are suitable for ideal conditions with diffuse sound fields. In reality, the sound field is far from uniform. It can be represented in the form of two fields: non-diffuse and diffuse.
				Non-diffuse sound field			Diffuse sound field

Non-diffuse sound fields are predominantly located in the mid- and high-frequency region and contain sound energy that is distributed in a plane parallel to the sound-absorbing surface (usually the ceiling). The reverberation time in a room is determined by the non-uniform sound field. This means that the practical value of reverberation time is significantly higher than the theoretical value calculated for a diffuse sound field.

The best way to reduce energy non-diffuse sound fields is sound absorption by wall-mounted sound absorbers. Sound energy can also be redirected to a sound-absorbing suspended ceiling by reflection or dispersion from furniture, equipment, and room cladding.

Breaking up the sound-absorbing area into small elements interspersed with a solid surface will increase diffusion and slightly reduce reverberation time.

Additional benefits of vertical sound absorbers

In many rooms for good acoustics it is necessary to reduce the noise level. The more sound-absorbing material, the correspondingly lower the noise level. Scientists have proven that reducing sound pressure levels (lower noise levels) in a room leads to a decrease in psychological stress - people begin to speak more quietly.

For rooms where Speech intelligibility is a priority, and C50 is more important than reverberation time. Although STI is partially dependent on reverberation time, it correlates better with the amount of sound-absorbing material in the room. Adding sound-absorbing panels to walls reduces reverberation time and improves speech privacy, which also results in lower sound pressure levels.

By the number of sound-absorbing materials The level of speech privacy and the level of sound pressure reduction can be calculated, but the reverberation time (RT) cannot be calculated, depending only on the amount of sound-absorbing materials.

Practical solutions with vertical acoustics

The main three factors that should be taken into account when installing sound-absorbing wall panels in a room are:

area that can be lined with sound absorber

mechanical strength requirements

aesthetic requirements

The first and easiest way is partial covering of walls with wall panels. From an acoustic point of view, it is best to install wall panels on two adjacent walls to avoid the effect of fluttering echoes.

Another way to install wall panels- break them into small sections and distribute them evenly along the wall. This can be done either geometrically or in any order. This way you can create your own unique design.

Another simple and functional way to place sound-absorbing material in classrooms or offices - installing a horizontal belt of wall panels at a height convenient for human height and using them as an information board. In this case, it is also preferable to install panels on at least two walls in combination with a sound-absorbing ceiling.

Concrete floor in the garage - what brand, thickness of the concrete screed, how to concrete it correctly and inexpensively, how to make it and level it, foundation structure