I recently went looking for some sound absorbing fabric to cover some windows and the door in my home office studio. The first place I walked into I knew I’d made a mistake. I know what sound-transparent fabric is, but sound absorbing and soundproof I didn’t know enough about. Apparently, neither did the people I spoke with.
After several very confusing conversations, I went home empty handed. I sat down and did some reading, a lot of research, and more reading. I decided to share what I found, so you also have a better idea when you go looking for acoustic fabric for different purposes.[toc]
Sound Absorption vs. Soundproofing
When comparing sound absorption and soundproofing, we are looking at how different materials interact with sound wave energy. Some materials will absorb sound energy, some will reflect it, and others will allow it to pass through, or transmit.
Most materials do a little bit of all three depending on the sound frequency. It may work better on mid to high frequency, or on low frequencies.
Sound absorption is how we reduce the reverberation or echo within a room. A material that has an absorption coefficient or Class tells you the amount of sound it will absorb within a set frequency range. If the absorption coefficient is 0.30, then 0.70 (or 70%) of the sound is being reflected or transmitted through the material, or a mix of both.
Soundproofing is how we prevent or block noise from being transmitted through walls, windows, and doors. It is usually a material that reflects or absorbs broadband of sound frequencies.
Concrete has a sound absorption coefficient of 0.03, so reflects or transmits more than 95% of soundwaves. Acoustic curtains have coefficients between 0.35 and 0.70, depending on materials and construction, what they don’t absorb, they transmit or reflect.
Fabrics that have an NRC (noise reduction coefficient) are mainly for absorbing sound, materials with an STC (sound transmission class) identify how well they block sound and are soundproofing. Sound absorption and soundproofing depend on what you are trying to do.
If you want to improve the sound inside a room, absorption is the way to go. If you’re going to prevent sound from entering or leaving a room, then you want to soundproof.
What is Sound-Absorbing Fabric?
Sound absorbing fabric is not soundproof. It will improve the quality of sound within a room, by decreasing reverberation and echo of the sound generated in the room. It may also marginally decrease transmission of some frequencies between rooms. Sound absorbing fabric is used in homes, theaters, recording studios, restaurants, and even churches.
Fabric curtains or panels absorb or soften reflected noise to improve the sound in large and small rooms. They control sound and are less expensive than some options.
Similar to sound absorbing panels, deflectors, and traps, the thickness, density, fullness, and placement of the cloth affect how well it will moderate sound. Pleating increases the thickness, and hanging the curtains 6” to 12” from the wall or window increases sound control.
The material used for acoustic curtains is often made of recycled polyester fiber. Spun and woven into soft, thick velour or velveteen like fabric, it softens sound by absorbing and reducing reflection.
The durable curtain is easy to maintain and available in multiple colors. Since it is hung in homes and large gathering places, it is also fire resistant.
Types of Acoustic Fabrics
Acoustic fabrics are used for draping rooms and absorbing noise, or for wrapping absorbent materials and allowing the sound through. Cloth of different weaves and densities interact with sound distinctly, so select a fabric for the purpose you want.
Sound Absorbing Fabric
Fabric that will absorb sound frequency waves is thick and porous. The waves enter into the fabric, and some become trapped in the fibers and folds and convert from sound energy into heat. Sound energy that makes it through the cloth hits the wall or window 6” to 12” beyond.
It is reflected into the curtain again. Some more noise will be absorbed. The waves that pass back through the curtain into the room will be softened and dampened. Echo and reverberation are controlled, and listening enjoyment is improved.
The best fabric is thick, 32-ounce velour type cloth. Heavy blackout curtains are good too, especially multi-layered curtains. Some fabrics have an NRC (noise reduction coefficient), the higher the value, and the better at decreasing reverberation, reflection, and echo.
Acoustically Transparent Fabrics
Transparent fabrics are used to cover acoustic panels, bass traps, and diffusers that are made of absorbent insulation. They cover and contain the fibers of the insulation while permitting soundwaves to pass through as if they weren’t there. Many fabrics are transparent.
To check if a fabric is transparent, hold it up to your mouth and blow through it. If the air passes easily through it, it’s transparent. There are different qualities of transparent materials. Look for cloth that is durable, strong, dust and stain resistant, and the color or pattern you want; if it is fire rated, even better.
Sound Proofing Fabric Thickness
Using fabric curtains alone to soundproof a room or office isn’t practical. Soundproofing fabric would need to be at least 2-inches thick.
Heavy 32 ounce (or heavier) velour will absorb sound, especially the lower, longer waves of bass frequencies, but it doesn’t block sound transmission. A less expensive option is sewing two or more layers together for a thicker fabric.
There are industrial “curtains” available with an STC rating which block and absorb sound. They are more like wall hangings than drapes.
They don’t bend like fabric drapes. They often have two layers of thin insulation quilting – like a quilted moving blanket – with an MLV (mass loaded vinyl) sandwiched in between.
The soundproof rating improves with the thickness of the MLV. Sound waves are absorbed by the quilted insulation layer but have difficulty penetrating the MLV.
This type of curtain is heavy and more rigid; it’s more of a barrier. The MLV adds 0.5 to 2.5 lb/ft² to the weight and raises the curtains to an STC between 25 to 33. It is also hung closer to the wall or window since the airspace between the wall and curtain are unnecessary.
Soundproofing Fabric Acoustical Properties
Materials that have an STC value identify how well they will block sound. Fabrics with an NRC value identify how well it absorbs sound. They may have both, or neither, it depends on if the manufacturer has tested them for sound proofing or sound absorption.
Some fabrics are tested directly over drywall to simulate curtains and determine their NRC rating. Set frequencies from 125Hz to 4000Hz are tested against the fabric, and the average is the NRC.
Look for the results of the frequency tests; they provide useful information. Higher numbers at different frequencies indicate what sounds the fabric will work with best.
The results for the frequency spectrum tell what frequency range the fabric absorbs best. Values of 0.02 for 125Hz and 0.05 at 250Hz indicate poor performance at low range frequencies or bass sounds.
Scores of 0.35 at 500Hz and 0.68Hz at 1000Hz indicate good control of mid to upper mid-range frequencies. Higher values like 0.78 and 1.0 for 2000 and 4000Hz indicate excellent control of higher frequency waves.
Best Acoustic Fabrics Reviews
There are thousands of fabrics available online and in stores claiming to have acoustic qualities. Some work well as acoustically transparent covers, and others will be better for curtains that absorb sound. Here are some reviews to get you started.
Guilford of Maine Sona Acoustical Fabric
Guilford manufactures an acoustically transparent cloth from 14.4-ounce polyester. Available in 12 colors, it is also fire rated. The weave and 255 thread count per inch allow the sound and air through but also mask the material it covers.
The fabric is used for speaker grills and works very well on diffusers, bass traps, and acoustic panels. It can also be used for curtain material.
The acoustically transparent fabric is non-reflective, so all sound passes through. The 60-inch wide cloth is sold by the yard, which means it covers more than a 44-inch fabric. For wrapping 2’x4’ insulation for bass traps, absorbing panels, and diffusers, one yard of fabric will do.
If you want to check how well the fire rating works, hold a scrap of the material 12” from a flame. Nothing should happen. Move the fabric sample 6” closer to the flame, and still, nothing should happen.
Move to 3” and then to 1-1/2”. If it produces smoke, catches fire, and turns to ash quickly, you should spray the cloth with a fabric fire protector.
Gray Burlap Fabric
Burlap has often been used for speaker grills and to cover acoustic panels. The open weave allows air and sound to pass through easily but is too tight to see through.
This is finely woven burlap with 225 thread count. It has a textured look and is available in gray, espresso, mocha, and nugget, plus other colors.
The burlap is acoustically transparent, so it works well for sound control projects. The 60” wide fabric is sold by the linear yard and weighs 10 oz/yd². Ironing wrinkles is near impossible, so buy it on a roll. The supplier I checked had 55-yard rolls.
The fabric isn’t fire rated, so if it’s near heat or flame, spray it with a fire retardant material. If you are using burlap to cover fiberglass or another fibrous material, it may not contain the fibers. Wrap the insulation in a breathable fabric of similar color first, and then cover with the burlap.
Guilford of Maine Network Acoustical Panel Fabric
Here’s another Guilford transparent fabric for curtains or for wrapping acoustic wall treatment. It weighs 16-ounces, +/- ½ an ounce per linear yard of fabric.
A linear yard of this cloth is 66” wide, making it a good cover for DIY acoustic panels. The fabric is made from 100% recycled post-consumer polyester, is durable, and very strong so won’t tear when stretching on panel frames.
The patterned cloth has a darker stripe on one side, and the reverse or back of the fabric has a lighter stripe. It can be used either way.
The width means linear one yard will easily cover the front and frames of a 2’x4’ acoustic insulation panel. Insulation has loose fibers that can pass through the material, so it is a good idea to wrap the insulation in a tighter woven transparent cloth first.
Guilford fabrics are often treated and fire rated class 1 or A. If you plan to cover more than 25% of the room with acoustic treatment, it is advisable to spray the fabric with a fabric fire protector.
The material can be vacuumed, brushed, or washed. The fabric has an NRC rating of 0.95 for transparency/absorption.
VelvetVelvet has a plush vertical fiber that is both transparent and absorbing. Available in multiple colors, in standard widths of 45”, it is better as curtain than for wrapping acoustic panels. Look for thicker and heavier cloth; it will provide better sound treatment.
Material, especially velvet, is often listed by weight. Light is 4.51-ounces (150 grams per square meter – GSM) or less a square yard, the medium is 4.52 to 10.32 ounces (350 GSM), and heavyweight is greater than 10.32-ounces. 18.88 oz/sq² (640 GSM) is common for window curtains, double it up with pleating, and it becomes an excellent sound absorber.
The weight doesn’t always reflect the thickness of the fabric. The type of fiber and the density of the weave are the determining factors for the weight of material.
Most velvet materials are not fire treated unless the company it is purchased from states it has been. The fabric used for curtains should be treated with a fire retardant, especially if it covers more than 20% of the wall surface. Ceiling baffles should always be treated too.
LA Linen 60-Inch Wide Natural Burlap
LA Linen is a US manufacturer of the fabric, including natural jute fiber burlap. The cloth is 60” wide, has consistent natural color throughout, is washable, durable, and doesn’t smell like old burlap.
As a natural material, it will have some scent and fiber dust, but that will dissipate over time. Hanging the fabric outside or steaming it will help dissipate it more quickly.
Burlap has an open weave which allows air and sound to pass through easily. It is a good fabric for wrapping acoustic panels.
However, due to the open weave, an under cloth may be necessary if the sound absorbing material or insulation has loose fibers. It is available by the yard, or in increments up to 100 yards.
Jute fibers are natural, so the burlap is biodegradable. It is also flammable and should be treated with a flame retardant if it is used to cover 20% or more of your walls. Anything draped from ceilings should be treated before being installed.
How to Use Acoustic Fabrics
Fabric may be noted for acoustic properties, or it may have acoustic characteristics you can use. Choose the fabric that will work best for what you want it for, whether transparent, absorbing, or reflective.
Soundproof Layered CurtainsBlackout curtains have two layers of fabric sewn together. The inner layer is designed to block 100% of UV and sunlight, protecting furniture and carpet from fading, plus cooling the inside space in summer and warming it in winter.
It’s usually solid black or white polyester. The inner layer is plush polyester available in multiple colors to complement your interior.
The material for both layers is triple weave, making it denser. It isn’t transparent, so it reflects light and absorbs noise coming through the window from outside.
The more folds the curtains have when closed to cover the window, the more sound they will absorb too. The sound is trapped in the thick fibers and folds, so less reflects into the room.
The fabric is machine washable and can also be vacuumed. However, it isn’t treated with a fire retardant, so keep away from open flame.
If used in a public place or office, they should be treated with a fire retardant. Remember, the double thickness blocks all sunlight from entering but not all sound, the more folds, the more sound it will absorb.
Acoustic panels absorb, trap, or diffuse sound. They are not designed to soundproof a room, but to improve sound quality within a room. They do this by removing sound build-up, echo, reverberation, and chatter.
The sound waves are absorbed into an insulation material like a sponge. The wave vibrates in the insulation fibers and is converted to heat energy, decreasing the number of sound waves returning to the room.
The fabric that is used to cover the panels is sound transparent. That means it allows 85% or more of the sound through to the absorbing fibers behind it.
Acoustic panels are available in 1-inch to 6-inch thicknesses. In most cases, the thicker the panel, the more sound conditioning it provides.
Panels can be expensive to buy, but you can make your own. 21 DIY Acoustic Panels, Ideas, and Plans have some great ideas and suggestions to help you out.
If using acoustic panels to control sound, it is recommended that a minimum of 20% of the walls be covered and even parts of the ceiling. Corners and surfaces opposite where a sound is generated are an excellent place to start.
Purchased panels are available in a variety of fabric colors, while DIY panels can be finished in any acoustically transparent fabric color or pattern.
ADW sells a set of four 1-inch thick sound absorbing panels that collectively cover about 24 square feet of wall. They’re available in a selection of colors and can be arranged to suit your style.
The panels have an NRC rating of 0.85, which means they can absorb 85% of the sound waves they receive. The panels are manufactured in the US and are easy to mount on walls.
Fabric Panels and Acoustic Baffles
Fabric panels are often mounted horizontally or flush with the ceiling. Acoustic baffles hang vertically from a ceiling or support structure near the ceiling. They both treat the sound reverberation and echo within a room.
Baffles, like panels, are made of insulation material wrapped in acoustically transparent fabric with a mounting strip along the long side. Manufactured baffles are often 48-inches long and 12 or 24-inches wide, and made of 2-inch thick insulation panels.
The thick insulation provides an NRC rating of 1.52, so fewer are required for improving the sound in a room.
The color choices are more limited when purchasing ready-made baffles. However, some companies offer custom color choices, or you can make your own.
Fabric selections include acoustically transparent for absorbing sound, durable ripstop cloth, or easy to clean vinyl. Vinyl is not a transparent material.
ATS Acoustic Baffles
ATS manufactures baffles using Roxul 60 mineral wool. A rigid insulation panel that they enclose in an aluminum frame with hanging tabs at the top. The whole panel is wrapped in acoustically transparent jute burlap.
Fabric Covered Walls in Rooms and Home Theaters
If you want to cover a wall or several with fabric and curtains aren’t what you want, there are metal or PVC track systems available. They are similar to framed panels but are limited in size only by the dimensions of the fabric. Fabric is available in widths up to 66-inches, and lengths can be 100 yards or more without a seam.
With the wall system, you aren’t limited to their fabric selection; any fabric will work. Pick a solid, print, team or corporate logo, or be creative and have your favorite wilderness or cityscape printed on fabric.
Wall coverings should be either fire retardant material or sprayed with a fire retardant. If the fabric fades, or you get tired of the color or pattern, the track system makes it easy, no nails or staples to remove.
The wall covering system is designed so even a DIYer can get professional looking results. The wall surface should be clean and sealed or painted before installing the track system.
Draw level lines where the top, bottom, and end tracks go. Install the mounting brackets for 1”, 2” or 4” thick panels. Clip the PVC or metal tracks – 45° miter cut where the corners meet. The track has a tuckable edge that holds the fabric in place.
Before installing the fabric, consider installing MLV (mass loaded vinyl) to block sound moving in or out of the room. Secure it to the wall within the frame.
Install sound absorbing insulation panels inside the frame to improve the sound within the room. The last step is to install the acoustically transparent fabric into the top groove, pull tight and push into the bottom groove and then fold and tuck the ends and corners. Several pairs of hands make the job easier.
If you decide to move or take down the panels, the fabric is easy to remove. Then uninstall in reverse order.
There are only holes where the mounting blocks were installed to patch. The track system is a great sound solution for home media or studios, meeting rooms, theaters, churches, and arenas.
Acoustic DividersAcoustic dividers can be used to improve the sound further, and don’t require installation to walls or ceilings.
The 24”x66” panels can be combined and moved where needed to improve sound quality.
They can be purchased ready-made and covered in the manufacturers color choice, or custom covered in your choice of acoustically transparent cloth.
No products found. Thick polyester curtains can be used to cover walls, divide rooms, or cover openings to reduce echo and reverberation.
Compression rods can be used to make the curtains portable and a more flexible way to improve sound control.
Curtain panel widths and lengths are readily available in a wide selection of sound absorbing fabric, or custom options are available.
Alternatively, you can make curtains to suit your decor and dimensions.
Sound Dampening BlanketsSound dampening blankets are similar to mover’s blankets or pads. They are thick quilted blankets with cotton/polyester filler. They absorb sound, vibration, dampen noise, and reduce reverberation.
Often used to decrease machinery sounds, they can be used in home theaters or studios to improve sound quality. For much more information on sound dampening blankets, please see our article Soundproof Blankets for Windows.
The 72”x78” blankets have loops attached to the top 78” edge for hanging.
Low-Frequency Bass TrapsLow-frequency corner bass traps are designed to fit where two walls or a wall and ceiling meet. Low-frequency waves tend to congregate in corners and create disturbing echoes and reverberations. The bass traps absorb the excess waves and improve the sound.
The traps are triangular prisms filled with sound absorbing insulation and wrapped in fire retardant acoustically transparent cloth. They can be purchased in 24” and 48” heights, and can be stacked in corners or hung where the ceiling and wall meet to provide 12-inches of deep low-frequency absorption.
If you don’t like the price of manufactured traps, check out 18 Ideas and Plans on How to Build DIY Bass Traps for less expensive options.
Fabric Wrapped Foam
Fabric wrapped foam 2’x4’ panels are available in 1”, 2”, ad 3” thicknesses. The manufacturers identify that the foam absorbs up to 65% of the frequencies in the low, middle, and high ranges it receives.
The panels are wrapped in durable, fire retardant polyester-nylon material. The panels can be hung on walls and ceilings to improve the quality of listening within a room.
Fabric Wrapped Ceiling Banner
Fabric wrapped ceiling banners are similar to acoustic baffles. The 2” or 4” thick banners are 4’ wide and 20’ long and can be customized to other dimensions.
The sound absorbing fiberglass insulation is covered in Guilford sound transparent cloth and is fire retardant. An aluminum stiffening rod attached to the banner is used to suspend it from the ceiling.
The beige colored banners work well to reduce echo and reverberation at the ceiling and have an NRC rating between 1.00 and 1.15.
Fabric and Panels Cleaning and Maintenance
The best way to clean acoustic fabric and panels is with a vacuum to remove dust and dirt accumulation. How often depends on how easy it is to access the fabric. If the cloth gets something spilled on it, blot the material as quickly as possible to remove the moisture.
If you take the fabric down to wash, ensure it is well rinsed, cleaning agents can damage the sound transparency and attract dirt, increasing the rate of soiling. Depending on the dimensions of the material, it may be better to have it dry cleaned.
Whether cleaning with water or industrial dry cleaning, note that it may remove fire retardants and change the appearance of the cloth.
Other Popular Soundproofing Methods
Fabric curtains, baffles, banners, or wrapping are some of the solutions for improving sound quality in a space or room. Here are some other materials that can be used with the fabrics, or independent of them.
Cork flooring is a natural, sustainable, eco-friendly solution to impact, echo, and reverb noise. It is used on floors and walls of theaters and recording studios to dampen sound.
Sound waves are broken down when they enter cork and diffuse. A 3/8” cube of cork has more than 40-million cells which trap and absorb sound waves, so it’s easy to understand how a 3/32” or 3mm thickness can block 10dB of noise.
Cork will absorb sound similar to fabric, and not reflect it like a hard wall. On walls, the cork will reduce sound vibration, decreasing sound transfer between rooms. When used on the floor, the cork will minimize impact noise and transfer between rooms on different floors.
For more information, take a look at the post: Is Cork Good for Soundproofing?
Acoustic Panels Studio Foam WedgesFoam wedge acoustic panels are 2” thick 12”x12” squares. They are available in different colors and from several manufacturers. The wedge design helps eliminate echo flutter and standing waves in home studios, media rooms, vocal and instrumental practice rooms, and theaters.
The 12” square panels are made of polyurethane foam and can be arranged on walls or ceilings to help clean up sound in a room. They are often combined with corner bass traps and other acoustic panels to decrease slap-back, reverberation, ringing, and echo.
Mass Loaded Vinyl
Mass loaded vinyl (MLV) is a thick, high density, flexible, rolled vinyl sheet that is used to block sound transfer between rooms and floors. It can be suspended from walls or attached to joists to prevent noise movement.
It is available in 1/16” thick or 1/2 lb/ft² (STC 20), 1/8” or 1 lb/ft² (STF 27), or 1/4” which is 2 lb/ft² and has an STC of 31. MLV comes in black, gray, tan or clear, as well as with a Mylar foil on one side.
MLV is more effective with mid to upper frequencies than low bass sound. MLV will only reduce the sound that encounters it. Noise transfer that bypasses it isn’t controlled.
TMS Mass Loaded Vinyl
TSM offers a 1/8-inch Mass Loaded Vinyl MLV (STC 27) in several dimensions manufactured from new material only.
It can be used in studios, bathrooms, businesses, apartments, even automobiles.
Anywhere that sound transfer needs controlling.
Soundsulate Mass Loaded Vinyl
MLV from Soundsulate is 1/8” thick and has an STC of 27. Original, non-recycled, odorless material is available in 4’-6” wide rolls up to 245-feet long and 4-foot wide rolls 255-feet long.
It helps reduce noise transfer in a home or business locations.
Use on walls, ceilings, under a carpet or floating flooring, in automobiles, or even wrap ducts and pipes to decrease mechanical sound movement.
Case study: Enhancing the Acoustics of an Office Space
A 20’x20’ office with 15-foot ceiling experienced enough reverberation and echo that four individuals conversing around a table had difficulty hearing what was said. The office had 3 concrete walls and a glass floor to ceiling partition wall.
There were also 3 windows in one of the concrete walls. The ceiling was exposed concrete painted white, and the floor epoxy covered concrete. The reverb time averaged 1.5 seconds.
Acoustic panels were suspended horizontally to control the reflection off the ceiling. The result was a decrease in the reverb time of 28%. One concrete wall was covered with an artistic floor to ceiling insulated mural, which further reduced the bounce time to 0.76 seconds.
The overall improvement of adding acoustic panels to one wall and the ceiling was almost 50% and resulted in a workspace where a conversation was possible.
Selecting the best fabric for your acoustic project is important. The more you know, the better prepared you’ll be, and feel.
My next visit to a fabric store was much more productive. My windows and door are now better covered to absorb sound.
I hope you found this article of assistance in your search too. Your comments and suggestions are appreciated. Share it if you know someone who would benefit from the information.