Are you trying to determine what the best acoustic fabrics for sound absorption and noise reduction are? Don’t scroll through pages of internet searches, let us help! We explain what acoustic fabric is and the different types, plus the difference between sound absorption and soundproofing.
We look at factors to consider when selecting acoustic fabric, how to test for acoustic transparency, and different ways to use acoustic fabric. To further assist you in your search, we also review eight different types of fabric.
Contents (Jump to Topic)
- What Is an Acoustic Fabric?
- Soundproofing vs Sound Absorption: What’s the Difference?
- Acoustic Fabric vs Regular Fabric
- Types of Acoustic Fabrics
- Is There a Soundproof Fabric?
- Best Acoustic Fabrics Reviews
- Key Factors to Consider When Choosing Acoustic Fabric
- How to Test if a Fabric Is Acoustically Transparent?
- Popular Applications for Acoustical Fabrics
What Is an Acoustic Fabric?
There are essentially three types of acoustic fabric, those that reflect sound energy, those that absorb it, and those that are invisible to sound energy. Cloth that reflects sound waves may be used to prevent sound from moving in or out of a room or building. Fabric that absorbs sound energy is often used for curtains to deaden sound energy reflecting off walls and even ceilings. When looking for sound absorption and noise reduction fabrics, sound-absorbing and sound transparent fabric are most helpful, depending on the purpose.
Acoustically transparent or invisible fabrics are textiles that allow sound waves to freely pass through and are commonly used to cover acoustic devices. They come in a variety of weaves, textures, materials, and numerous colors.
Acoustically transparent fabrics are invisible to sound waves between 20 HZ and 20,000 Hz, the normal range of human hearing, and don’t degenerate the fidelity. An audio speaker is covered with acoustic fabric that offers minimal resistance to the soundwaves, ensuring full delivery of the sound.
To properly test the acoustic qualities of a fabric, a third-party test using ISO 10534-2 should be completed. The test involves placing fabric over a 5” thick piece of sound-absorbing foam with a known noise reduction coefficient (NRC) value. Sound frequencies are then tested against the fabric covering the foam to identify how much sound reflects, passes through, or is absorbed.
Comparing the results determines what acoustical use the fabric may have. An NRC value of 0 means the cloth fully reflects the sound while a rating of 1.0 means the sound was absorbed. Fabrics that neither reflect nor absorb would be deemed acoustically transparent.
To qualify as acoustically transparent, the cloth must allow the sound energy uninterrupted movement. That means sound waves neither reflect nor absorb as they pass through it. A quick and easy test is the ‘blow through’ test. Hold the fabric close to your mouth and blow through it. The easier it is to blow, the more transparent the fabric.
The light test is another way to check the acoustic transparency. Hold the fabric near a light and observe how much light penetrates, the more light the greater the transparency. Sound transparency can also be measured using ASTM C-423-90a, with fabrics achieving greater than 95% being highly transparent to sound.
Soundproofing vs Sound Absorption: What’s the Difference?
The main difference between soundproofing and sound absorption is what you are doing with the sound. Soundproofing is attempting to block as much sound from entering or leaving a room using different materials and construction practices. Sound absorption is using devices or materials to absorb sound waves to improve the sound quality within a room.
Soundproofing is attempting to block sound waves or vibrations from penetrating walls and enter or exit a room or building. It commonly involves increasing the mass of walls, decoupling to minimize vibrational pathways, and increasing the sound absorbency of the walls. Additionally, it also means sealing the walls, doors, windows, and other openings to prevent sound waves from sneaking in through openings.
Sound absorption is using devices affixed to walls and ceiling to treat the sound within a room to improve the quality of sound and listening. The devices allow sound waves to enter and convert to thermal energy, thus degrading the waves and reducing or canceling them out.
The amount of absorption depends on the purpose of the room; an office commonly requires less treatment than a recording studio. Absorption devices reduce reverberation, echo, ringing, and standing waves within a room.
Acoustic Fabric vs Regular Fabric
Most fabrics have some acoustic qualities that reflect or absorb sound waves. Acoustic fabrics, however, reflect, absorb, or let sound move through them to improve the sound quality. They have been third-party tested for reflectivity, absorption, or transparency, and commonly have an NRC rating. Some manufacturers design and produce cloth to be transparent, while others take an existing product and have it tested for transparency.
The key difference between regular fabrics and acoustic fabrics is functionality and breathability. The fabric should be durable, hold its shape, and be acoustically breathable. Although many fabrics may pass the breathability test – blowing through the fabric – they may not be acoustically breathable.
Some fabrics may be identified as acoustically transparent since they allow air through but unfortunately, this method doesn’t identify if all sound frequencies will pass through. Some textiles are transparent to mid-range frequencies but not low or high-range frequencies, resulting in a flattened sound.
An NRC rating is often associated with acoustic fabric; however, it is important that the test results be available too. Even some acoustically transparent fabrics, such as those composed of polyethylene, which has an NRC 0.95, acoustically deflect or block frequencies below 200 Hz and above 2000 Hz, which will flatten the sound. So, although identified and rated as a transparent fabric, it may not be desirable for some applications.
Types of Acoustic Fabrics
Acoustic fabrics are manufactured from various natural and manmade fibers and may absorb, reflect, insulate, or be acoustically transparent to sound waves. They come in different weaves and textures, and a plethora of colors. It is important to select a fabric that suits the purpose.
Sound Transparent Fabric
Sound transparent fabrics allow sound waves to pass through without distortion and are used to wrap or cover sound absorption devices and audio speakers. The fabric is acoustically invisible and doesn’t degrade sound fidelity. The ‘blow through’ test is a helpful method to determine the breathability of a material if it isn’t identified as acoustically transparent and accompanied with ASTM C-423-90a results.
Acoustically transparent textiles do not interfere with sound passage and are commonly used to cover audio speakers and sound-absorbing panels. To prevent sagging over time, some manufacturers use polyesters or high percentage polyester blends since they aren’t affected by humidity the way natural fibers, nylon, or rayon are. Acoustically rated fabrics are also often identified as flame retardant too.
Although the NRC rating is often sought, it is wise to check the test results across the frequency spectrum so problems such as those identified with polyethylene fabrics don’t occur. Some professionals recommend a high NRC rating and others 0 to 0.25. However, it is sound transparency that is important, especially for sound-absorbing panels and speaker covers.
Fabrics stretched over a sound-absorbing panel need to allow sound through so it can be absorbed in the panel’s core material. So, its breathability is important to improve the overall NRC rating of the sound-absorbing panel.
Sound Absorbing Fabrics
Sound absorbing fabrics should have a high NRC rating, although low values do improve noise control. Whether used for baffles, window and door curtains, partitions, or wall coverings, the higher the NRC the better the material will be at reducing sound movement. The fabrics help soften hard reflective surfaces and mask openings to improve auditory clarity and decrease background noise. They are an economical way to improve sound control and add color to a room.
Absorbent fabrics hung over walls, windows, and doors help decrease sound transfer and reflection, thus reducing reverb time and echo. Plus, they minimize noise entering or exiting a room.
There are hundreds of colors and patterns of fabrics, many are Class A fire rated, don’t pill or fuzz, and have good tear strength. There are fabrics that are fade-resistant and Velcro compatible too. Most sound-absorbing fabrics work better with frequencies above 200 Hz and are better with mid and high-range frequencies.
Fabrics hung flat or pulled tautly will absorb fewer sound waves than loose hanging material with pleats or folds which provide a thicker barrier profile. The heavier the material also will absorb more, and often has a higher NRC rating. For example, a 13oz polyester Velour may have a Sound Absorption Average (SAA) of 0.92 and NRC of 0.95, while a 20 oz velour an SAA of 0.96 and NRC of 0.95, and a 32oz a 1.04 SAA and NRC of 1.05. Acoustically rated fabrics should include charts and graphs of their performance across tested frequencies.
Sound Insulation Fabric
Sound insulation fabrics are used to reduce sound traveling from one room or building to another. The cloth often combines elements of sound absorbency and reflection to improve sound clarity and block unwanted noise penetration. To absorb and reflect sound means fabrics are often multi-layered, with one side being absorbent and the other reflective. The product remains flexible but is heavy and hangs like a ceiling-to-floor curtain.
Commonly a layer of 21oz/yd2 (500 g/m2) velour lined with dense 810g/m2 PVC-poly cotton blend layer, or similar combinations, are hung as light and sound-canceling curtains. In some applications, an additional layer of 500 g/m2 velour makes a 3-layer combination, while doubling provides a 4-layer combination, and even greater sound control.
To increase noise reduction and flexibility, two PVC-lined velour panels can be hung on tracks with an air space in between. The wider the air space, the greater the sound deadening abilities of the curtain.
The denser the material and greater the air space between layers, the greater the sound control provided. The curtains can cover walls, windows, and doors or be used as moveable room partitioning walls to decrease sound movement in or out of a space, room, or building.
The velour is available in numerous colors and weights, while the PVC-polycotton layer has more limited color options. For further protection and to meet fire codes, the materials also are Class 1 fire rated.
Acoustic Felt Fabric
Acoustic felt fabric may be natural wool, synthetic material, or a blend of recycled natural and synthetic fibers. The felt ranges from 11oz/yd2 to 50oz/yd2 or greater. It is sound absorbing and commonly short sheared to minimize pilling. The felt is available in a variety of colors and thicknesses and may be used to cover walls, ceilings, sound panels, and furniture. It is also low VOC and fire-rated Class A.
Thicker felt fabric has a higher NRC of 0.9 or greater sound absorbency than thinner 0.04” felt which has a 0.04 NRC. Thinner felt is also more acoustically transparent. Thick, 1/4” to 1” felt material is often pressed into self-adhesive panels with different shapes and surface reliefs for artistic applications on walls and ceilings.
Thinner felt is lightweight and cuts with scissors or knife, bendable, and easy to install for a multitude of sound applications. Thicker pressed felt material, although light, is often fabricated to be more rigid, shape-retaining, and is more difficult to cut.
Multi-dimensional acoustic felt webs, baffles, and grids offer a greater sound control option too, with NRC values reaching 1.20. They provide high sound attenuation and an artistic element to both residential and commercial locations.
Acoustic felt fabric is durable, impact and tear-resistant, and has some elasticity so it won’t slump with humidity. Felt fabric is not only sound absorbent, but it also provides thermal insulation too.
Speaker Fabric Cloth
Speaker cloth needs to be 95% to 100% acoustically transparent across the frequency spectrum to prevent sound delivery distortion. It should allow frequencies between 20 Hz and 20 kHz to easily pass through. Check that the fabric has been ASTM C-423-90a tested and the results are available. As noted above, polyethylene is identified as acoustically transparent but blocks or reflects frequencies below 200 Hz and above 2000 Hz, which will flatten the sound.
Speaker cloth is available in dozens of fade-resistant colors and in durable synthetic, natural, and blended fabrics. It is used to cover audio speakers, sound-absorbent panels or traps, and musical instrument openings. Commonly an open mesh or grill type weave, some synthetic materials are non-woven fabrics. Custom grill cloth is also available and can be printed in multiple color designs or images to suit the décor.
Speaker cloth is used in the professional music industry and by DIYers for home studios and theaters. Many speaker fabrics are moisture repellant to prevent sagging, mildew, and dust resistant, fire-rated for your protection, infrared transparent for remote control access, and easy to use. For the best sound delivery, always look for speaker fabric that has been tested to be sound transparent.
Is There a Soundproof Fabric?
There are fabrics that are more sound absorbent or reflective than others, however, there are no fabrics that are soundproof. Mass-loaded vinyl (MLV) by itself is probably the best ‘fabric’ for blocking noise. Hung on walls or used in wall, ceiling, and floor construction, MLV reduces airborne sounds and impact noise.
MLV is available with or without a sound-absorbing foam backing, and can also be used to line curtains to improve sound control. Color choices are limited but the vinyl can be painted to blend or complement most décors.
MLV is a flexible barrier material that reflects and blocks sound waves to prevent noise penetration. It is available in different thicknesses and densities, with the heavier material stopping more noise. Made of nonporous vinyl, it is durable, flexible, and water-resistant.
The reflecting mass element is often calcium silicate or barium sulfate. MLV has one of the best mass to thickness ratios. It does not absorb sound; it blocks it by creating a sound wave reflective barrier.
Best Acoustic Fabrics Reviews
Acoustic fabrics may absorb, reflect, or be transparent to sound waves and can be purchased online or in local shops. There are thousands of acoustic fabrics but they should be third-party rated and have the test results available, otherwise, there isn’t much to support the claim. To help get you started, here are some fabric reviews.
Key Factors to Consider When Choosing Acoustic Fabric
Acoustic fabrics improve sound quality by reducing reverb, echo, and noise transmission by tuning the sound we hear. They absorb, reflect, or are transparent to sound waves and help improve the auditory environment within a room or building. Look for fabrics that have been third-party tested with certified absorbency, reflection, or transparency, plus are Class A fire rated.
Transparency / Breath-ability
Acoustic transparency is important for speaker grills and sound-absorbing devices. The cloth allows the sound to travel through unimpeded, so you hear the cleanest sound from a speaker or maximize the absorbency of the core material in an absorber. Whether synthetic, natural, or blends, unbacked fabric commonly has an open weave and is breathable – it is easy for air and sound to travel through.
The functionality is being able to use the fabric for the intended purpose. A cloth may be acoustically transparent but tears too easily when attempting to stretch it. It could also sag or ripple when exposed to humidity.
Most polyester or acrylic fabrics are hydrophobic and immune to humidity; however, some are too stretchy and difficult to square the weave with the frame. Additionally, polyethylene fabrics, although breathable and sold as transparent, reflect sound waves below 200Hz and above 2000Hz, making for a flattened sound.
Most acoustically transparent fabric is thin in comparison to sound absorbent material. Acoustically absorbent fabric needs to be thick to effectively control low-frequency sound waves – the thicker the better. Bass frequencies require 2” to 6” of material to absorb and degrade the wave, which may not be practical with fabric.
However, heavy drapery hung with thick folds or pleats provides a deeper treatment than cloth pulled tautly. Additionally, providing an air gap between layers of fabric is effective too. Thick, plush, 32oz, or heavier velvet or velour will provide excellent sound control.
Acoustic curtains help control low and mid-range frequencies. Pleating helps the fabric hang in folds or loops to increase the treatment thickness. The deeper the pleat, the better as it exposes more surface area to the sound waves, improving sound attenuation.
When fitting curtains to control sound, 50% extra width provides minimum pleating fullness while 100% is recommended. For example, to cover a 10’ surface order 15’ for 50% fullness and 20’ for 100% fullness. The deeper folds provide better low-frequency control. To allow for deeper folds, the curtain rails should be 6” to 12” away from the wall or window surface.
Acoustic panels for walls and ceilings need not look industrial or drab. Greater color choices and patterns, panel shapes and sizes, and composition ensure acoustic treatment is aesthetically pleasing. Whether designer, architect, or DIYer, acoustic treatment can inspire, decorate, and compliment any décor while attuning the sound quality.
Acoustic fabrics traditionally were black, brown, tan, or gray. However, that has changed and the fabric color choices are almost unlimited. Technology has also played a role, allowing multi-colored images to be printed on acoustic cloth for a personal touch.
Colors are also often fade-resistant for a longer return on your investment. So, choose a fabric that is aesthetically pleasing to acoustically improve the sound quality of your studio, home theater, or office.
How to Test if a Fabric Is Acoustically Transparent?
Acoustically transparent fabric allows sound to pass through unimpeded. It neither absorbs nor reflects sound waves, so is acoustically neutral. Transparent cloth is ideal for audio speaker covers or sound-absorbing panels as it doesn’t interfere with the sound movement.
There are three methods for identifying the transparency of a fabric.
The first method is the breathability test – the easier it is to blow through a single layer of fabric, the greater the likelihood it is acoustically transparent.
The second method is the light test – holding a single layer of fabric up to a light source and observe the amount of light coming through the fabric. The more light, the greater the fabric’s transparency.
The first two methods are easy and free, but not 100% reliable.
The third method is more difficult and costly, but much more reliable. It is often done by interested third parties who may charge users for the results, or publish them for free for the public interest. The laboratory test, ASTM C-423-90a measures the acoustic transparency of a fabric. Fabrics that achieve results of 95% or better are considered highly transparent.
Popular Applications for Acoustical Fabrics
Acoustic fabrics are used for speaker grills, sound-absorbing panels, upholstery, curtains, baffles, acoustic dividers, bass traps, and other sound attenuating devices. They are used in home and commercial theaters, studios, offices, plus living rooms and bedrooms, meeting rooms, restaurants, churches, auditoriums, and many other locations. The fabric may help improve sound quality by reflecting, absorbing, damping, or soundproofing a room or structure.
Acoustic panels are often covered with acoustically transparent fabric to ensure the sound waves fully enter the absorptive core material. Panels improve the sound quality by reducing the sound energy, thus decreasing echo, slap, and reverberation. The color of the cloth often compliments the room, and can even portray images or messages.
Acoustic fabric allows more sound through into the core where it is absorbed and the sound energy converted to heat. The open weave of the cloth and sound transparent fibers permit free movement of all frequencies for maximum sound treatment. To ensure loose core fibers don’t become airborne, a transparent under cloth may be required too.
Acoustic panels may be square, rectangular, or multi-sided. To ensure the cloth covering has a professional look, the transparent cloth needs to be thin to prevent bulky folds, strong so it can be pulled taut, and hydrophobic to prevent ripples or puckering. Use fabric colors and panel shapes to create attractive acoustic displays to treat and improve the sound in any location.
Fabric Wall Upholstery
Fabric wall upholstery may be applied to wall surfaces in lieu of paint or wallpaper. The fabric may cover built-in acoustic panels or audio speakers. It may also be used to soften hard wall surfaces to improve sound quality. The fabric adds texture, color, and other aesthetic qualities to otherwise plain surfaces.
Upholstery on walls can also be in the form of wall hangings or tapestries. Often thick fabrics that absorb sound, they may hang in small or large rooms to control reverb and bounce to improve sound quality. The fabric may be lined with MLV to prevent sound transfer to or from locations too. Wall fabric is often a tighter weave and absorbent, making sound control more attractive.
Wall upholstery can be applied directly to a wall surface or be mounted on frames or tracks so there is an air gap between the cloth and wall to further enhance sound control. Many acoustic fabrics are fade and mildew resistant, and available in a multitude of colors, patterns, and textures. They will improve sound attenuation and visual aesthetics.
Sound Absorbing Curtains
Sound-absorbing curtains commonly are heavy, 32oz or heavier velvet or velour. They may be double-sided to increase weight and absorbency, or MLV lined to both blackout light and reflect outside noise. The heavy cloth is available in many attractive colors and patterns to enhance visual aesthetics.
The thick curtain cloth should be hung 6” to 12” out from the window surface, and be pleated. The more folds or bends a curtain presents, the greater the frequency range absorption the curtains provide. Curtains should also be floor to ceiling to prevent sound seepage around the fabric covering.
To further improve sound control, multiple layers of curtains are recommended. Suspending one layer of 100% pleated curtains 6” from the wall, and another layer 12” from the wall, will greatly improve the sound attenuation.
Adding an intermediate MLV layer between the two heavy curtains will further enhance sound control and quality. In larger spaces, short curtains are often suspended from the ceiling to control echo, reflection, and reverberation.
Suspended acoustic ceiling tiles or panels may fit within a T-bar track, fasten or hang from a drywall ceiling, or hang as baffles from the ceiling or roof framework. The core material of the tiles or panels is commonly rigid stone wool or fiberglass covered with fire-rated acoustically transparent fabric.
The suspended ceiling tiles or panels absorb reverb, reflection, echo, flutter, and slapping for a more accurate and enjoyable listening experience. The tiles also absorb sound from both surfaces, helping to control impact noise and reflection from above too.
The fabric weave needs to be breathable but also tight enough to encapsulate the core material to prevent particles from becoming airborne. Additionally, it should be hydrophobic to prevent sagging and be strong enough to pull taut.
Color choice is broad but should complement the room’s color scheme and purpose. Suspended ceilings are common in recording studios, theaters, auditoriums, gathering places, offices, and many other residential and commercial locations.
Fabric ceiling panels or tiles may be 1-1/2” to 6” thick, with the thicker cores providing greater sound control. To reduce costs, some installers use the thicker panels at reflection points and the thinner tiles to cover the rest of the ceiling.
For better noise control over listening or monitoring locations, a 12” to 16” deep cloud panel is often suspended for truer sound. Again, the more acoustically invisible or transparent the fabric, the better the results.
Sound blankets may be common wool blankets, quilted moving blankets, or manufactured multi-layered acoustically designed sound absorbing blankets. The main purpose is to absorb sound and prevent reverb, echo, or other disruptive sounds. Whether the sound blanket is a single thickness of absorbent fibers or an industrial-strength sound-absorbing barrier blanket with multiple layers, the purpose is much the same.
Hung on walls, over windows or doors, or around machinery, the sound blankets allow sound waves to enter and be absorbed. They help degrade the sound energy to improve the sound quality and the auditory experience. Acoustically transparent cloth-covered quilted blankets with fiberglass or stone wool batting for fill provide greater control than most sound-absorbent fabrics.
Industrial sound blankets often dispense with the quilting stitch as it thins the blanket and reduces its potential. An acoustically transparent material often covers one face of the absorbent core, and a reflective or MLV material finishes the other face.
Most blankets or quilts have an NRC of 0.3 to 0.5, while thick industrial blankets often achieve NRCs of 0.8 and higher. The thicker and heavier the blanket, the lower the frequencies it will control, so weight and thickness are important.
Acoustic Room Dividers
Acoustic fabric is commonly used to wrap free-standing room dividers. The fabric is acoustically transparent and covers the absorbent core material. Some partitions use speaker cloth while others a less see-through weave. Although most commercial dividers are covered in drab colors or those reminiscent of the 1960s, the color choice is almost unlimited, and can even display photos, artworks, or messages.
Acoustic dividers improve sound and conversation quality and have an NRC in the 0.85 range. The height of the dividers is commonly between 5’ and 6’ high, making them ideal for improving the sound heard by those seated near them.
Acoustically transparent cloth is applied to both sides of the dividers to maximize the absorption of the core material. A common fabric is Guilford of Maine’s acoustic fabrics which are also fire-rated. The cloth is transparent, strong, durable, and doesn’t sag with humidity.
Hanging room dividers may be narrow floor to ceiling panels that move on a track and act as temporary, yet solid dividers, or they can be similar to multi-track curtains. Solid dividers are thicker and heavier, and the covering allows sound to be absorbed by the core material.
Acoustical curtain room dividers are also track mounted at the top and manually or electronically open or close. The heavy velour or velvet curtain fabric may be double thick or lined with MLV, or be multi-layered and tracked with two heavy absorbent curtains sandwiching an MLV ‘curtain’. The weight and thickness, again impact the sound control, with an NRC of 0.8 or higher.
Bass Traps are thicker than sound-absorbing panels and commonly fit into corners. They are used to absorb low or bass frequencies, although they do absorb mid and high-frequencies too. The traps are often mounted in corners where two hard surfaces meet, and low frequencies reverberate and echo into disruptive standing waves. The panels may be triangular in shape to fit the corner, or are rectangular and straddle it.
Many bass traps use mineral wool or fiberglass as the core material to absorb the sound waves. The thick insulation absorbs the lower waves and converts the energy to heat, thus decaying the sound energy wave and improving sound quality. The insulation is covered with acoustically transparent cloth the maximize the sound absorption and to prevent core particles from becoming airborne.
Acoustically transparent fabric options for covering traps come in dozens of colors and patterns, and can even depict photo art choices. The open weave is invisible to sound waves, so it doesn’t absorb or reflect noise, thus improving absorption by the core. Don’t settle for black, gray, or tan, go for colors that compliment, brighten, and inspire.
Acoustic fabric may absorb, reflect, or be transparent to sound waves, so selecting the correct fabric for the task is important. Hopefully, you now have a better understanding of the different types of acoustic fabrics, their uses, how they are tested, and what to look for. Select the fabric for the task, the color for aesthetics, and stay within your budget – start small and upgrade over time.