Soundproofing
Soundproofing refers to minimizing unwanted noise and noise pollution by preventing sound from entering or leaving certain spaces. Soundproofing materials and products function as silencers, mufflers, and insulation, absorbing excess sound in rooms, chambers, and around equipment. This creates quieter environments for worker safety, accurate product testing, audio recording and mixing, research, and more.
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The History of Soundproofing
The earliest audio recordings were made using the phonautograph, invented by 脡douard-L茅on Scott de Martinville in 1857. This device captured sound waves as lines on paper or glass, and the first known recording was the French folk song "Au Clair de la Lune" in 1860, which still exists today. As technology advanced, the world became increasingly noisy, leading to a greater need for sound control.
Modern soundproofing began in the 1890s thanks to Wallace Clement Sabine, a Harvard physicist. He was assigned to improve the acoustics in Harvard鈥檚 Fogg Art Museum lecture hall. Sabine was the first to measure reverberation time, which he found to be 5.5 seconds. By experimenting with different seat cushions and sound-absorbing materials, he advanced acoustic science and later used these principles to design Boston Symphony Hall, which opened in 1900 as the first building with scientifically engineered acoustics.
Throughout the 20th century, noise levels increased rapidly. By the 1960s and 1970s, the impact of noise鈥攂oth physical and psychological鈥攂ecame apparent. Loud concerts led to hearing loss. In 1978, the EPA鈥檚 Office of Noise Abatement and Control reported that about 20 million Americans were exposed to dangerous noise levels. Occupational exposure above 85 decibels affected nine million workers in 1981, rising to 30 million by 1990. Prolonged exposure above 85 decibels can cause lasting ear damage.
To address noise pollution in public spaces, industry, and studios, engineers and lawmakers developed solutions. The 1972 Noise Control Act established national noise standards for public health. During the 1970s, the U.S. and other countries began installing noise barriers along highways鈥攏ot for drivers, but to shield nearby residents from excessive traffic noise. One of the first barriers was built in Arlington, Virginia, along I-66, while Los Altos, California saw one of the earliest scientifically designed barriers in 1970. Since then, agencies like the FHWA and SHA have made it a state responsibility to set traffic noise abatement policies.
Today, as noise issues become more significant, advancements in technology and comprehensive standards continue to improve soundproofing and noise control for health and safety.
Benefits of Soundproofing
Modern life is filled with noise, which can negatively affect both physical and mental well-being. Even though noise may be fleeting, repeated exposure can lead to temporary or permanent hearing loss, stress, sleep disruption, lower concentration, reduced productivity, and less peace of mind. Soundproofing solutions help minimize these problems. Additionally, soundproofing enhances recording quality and is available in many flexible and adaptable forms to suit different needs.
How Soundproofing Works
Soundproofing materials function by absorbing noise, dampening sound vibrations, blocking sound at the source, or combining these methods for effective noise control.
- Sound Absorption
- Utilizes soft, porous, open-celled foams such as polyurethane foam, which trap sound waves inside their network of non-reflective cells. The larger the sound barrier surface area relative to open space, the better the absorption. Anechoic chambers line walls, ceilings, and floors with corrugated foam wedges or pyramid-shaped panels, which absorb more sound than flat foam or basic acoustic panels.
- Vibration Dampening
- Minimizes the transmission of vibration energy between rigid surfaces, which can carry vibrations at various frequencies. Product testing facilities and acoustic research environments use vibration dampening to achieve near-total noise control. This is typically done using anechoic chambers lined with acoustic foam panels, special drywall, and acoustical ceilings to absorb nearly all sound produced by machinery or equipment.
- Sound Barrier Creation
- Sound barriers are dense structures that block noise sources and reduce their impact. Often constructed as high-density walls, these barriers are frequently seen along roads or highways to reduce traffic noise, but they are also used as firewalls, bulkheads, pipe wraps, and cab floors.
Soundproofing Design and Customization
When creating soundproofing equipment, manufacturers determine whether the goal is to enhance sound quality within a room or prevent sound from escaping. This decision influences the type of soundproofing solution required. For example, anechoic chambers are excellent for improving in-room acoustics, though they are not primarily intended for blocking outgoing noise.
To fabricate soundproofing products, manufacturers use materials engineered to absorb sound. Common materials include rock fiber wool and porous substances like urethane open cell foam. Rock wool provides complete sound absorption and insulation, while porous materials partially allow sound waves to enter and trap them. Wall panels and baffles may also use perforated metal construction.
Manufacturers can customize soundproofing equipment to match interior aesthetics, often covering acoustic panels with fabrics that blend into building decor. Custom options also include size (square footage), thickness, and scope, ensuring the solution fits the intended space and requirements.
Types of Soundproofing
- Active Noise Control (ANC)
- Also known as active noise reduction (ANR), this technique uses a carefully engineered sound to cancel out unwanted noise, typically low-frequency sounds. ANC technology is found in headphones, speakers, and microphones.
- Acoustic Flooring
- Essential for minimizing noise caused by machinery, instruments, or foot traffic on hard floors. Carpets and fibrous materials can provide significant soundproofing, while hard floors may require specialized solutions. Acoustic flooring consists of insulation and shock-absorbing layers, topped with acoustic foam or mineral boards.
- Soundproofing System
- Facilities exposed to high equipment noise use soundproofing products like acoustic flooring for vibration control and overall noise reduction. Soundproofing systems cover large areas with acoustical ceilings, baffles, foam, and panels. Their sound-absorbing materials reduce echoes and reverberations. Music venues and performance halls use these systems to maintain audio clarity and prevent unwanted noise or echoes.
- Acoustical Ceiling
- A suspended ceiling system using sound-absorbing panels or tiles for effective noise control in specific spaces.
- Acoustic Baffle
- An acoustic component that can replace or supplement acoustical ceilings, hung vertically from ceilings. Acoustic baffles usually contain one or two cores of stable, medium-density glass fiber.
- Acoustic Foam
- Controls noise and provides insulation by allowing sound energy to enter the foam, where it is absorbed and prevented from escaping. Acoustic foam lines reflective surfaces in gyms, studios, clubs, halls, and churches to reduce unwanted sound.
- Acoustic Panel
- A wall-mounted sheet of sound-absorbing material with a frame, internal absorbent core, and an outer cover. Acoustic panels are excellent for blocking external noise and are widely used in cafes, offices, and industrial facilities.
- Acoustic Curtain
- Heavy-duty drapes or panels made from specialized materials to block noise between spaces. In industrial settings, acoustic curtains surround equipment to absorb and contain sound.
- Anechoic Chamber
- A specialized soundproofing solution that provides completely 鈥渄ead鈥 space. Anechoic chambers are widely used in recording studios, acoustical research, and equipment testing.
- Sound Isolation Room
- Also called audiometric booths, these rooms are used by audiologists and hearing specialists for hearing tests and research on how sound behaves.
- Locally Applied Soundproofing
- Includes mufflers, grommets, shocks, and vibration isolators applied directly to equipment. Computers often incorporate soundproofing materials, and office workstations may be placed in soundproof or semi-soundproof rooms.
- Acoustical Blankets
- Made with polyvinyl chloride outer shells and acoustic batting, these blankets can be hung or framed around equipment to absorb and block noise.
- Acoustical Enclosures
- Used to stop sound from traveling between areas. Examples include recording booths, industrial enclosures, highway noise barriers, and noise barrier walls.
- Acoustic Flooring
- Multiple layers of sound-absorbing material beneath the floor surface help reduce noise transfer between levels in multi-story buildings.
- Barriers
- Dense layers used to separate or block noise from entering or leaving a space. Barriers are commonly used for bulkheads, firewall treatments, cab floors, and pipe wraps.
- Cloud Panels
- Similar to acoustic baffles but suspended horizontally from ceilings to absorb sound from above.
- Damping Materials
- Help control vibration and structure-borne noise, often through friction or time-based damping. Used for sheet metal panels, cab enclosures, boat hulls, deck plates, and HVAC systems.
- Diffusers
- Scatter sound waves across a surface, changing their direction so listeners hear sound evenly from multiple directions.
- Intake Silencers
- Reduce noise and low-frequency pulsations at blower inlets.
- Isolators
- Reduce vibration by providing greater attenuation in one direction, often installed between two surfaces, like generator pads, to absorb vibration and noise.
- Modular Acoustical Panels
- Portable panels鈥攕uch as partitions, wall panels, baffles, and privacy screens鈥攆or flexible soundproofing.
- Noise Pollution
- Any unwanted or unpleasant sound. Noise reduction aims to decrease noise pollution by blocking, absorbing, or isolating intrusive sound waves.
- Reflectors
- Regulate the amount and direction of sound reflected from a surface, especially in acoustically sensitive environments.
- Silencers
- Lower sound levels through absorption, reaction, or a combination of mechanisms.
- Sound Absorbers
- Materials designed for noise control, used extensively for treating large surfaces. Sound absorbers are found in machine enclosures, housings, industrial, medical, marine, and transportation settings.
- Sound Barriers
- Wall structures made of dense materials to minimize noise along highways by blocking traffic sounds.
- Sound Insulation
- Also called acoustic insulation, it absorbs sound waves and prevents unwanted noise and vibrations from passing through surfaces.
- Sound Proofing
- Describes all methods used to reduce sound intensity in a given area.
- Soundproofing Materials
- Products designed to block or reduce noise within a space by preventing sound from entering or escaping.
Soundproofing Applications
Noises may be airborne, such as voices, music, or traffic, or structural, such as vibrations from machinery, footsteps, or sounds from building systems like plumbing and HVAC. These noises can create disruptive or uncomfortable environments at home or at work. High equipment noise can also cause distractions, hinder communication, and, in industrial settings, lead to permanent hearing loss. Soundproofing addresses these issues by minimizing noise and creating more comfortable spaces.
Soundproofing products and components are essential in many environments, supporting applications ranging from industrial noise control to personal hearing protection. Medical hearing clinics and product testing labs, like computer test chambers, require soundproof rooms to accurately measure decibel output. Soundproofing is also critical in recording studios, theaters, performance halls, and for quieting equipment such as computers, home appliances, vehicles, and watercraft.
Safety and Compliance Standards for Soundproofing
Federal regulations define allowable noise levels in workplaces, schools, offices, airports, and public spaces, often requiring soundproofing to maintain safe and functional environments. The EPA enforces noise emission standards, including the Clean Air Act 201.7641, which targets noise abatement. Facilities must ensure their soundproofing systems comply with all applicable federal requirements. For workplaces, Occupational Safety and Health Administration (OSHA) standards are also crucial for safety and compliance.
Independent organizations provide additional standards for safety and system performance. ISO 91.120.20, published by the International Standards Organization (ISO), details sound insulation standards for indoor acoustics. ISO standards are often used outside the U.S., while ASTM International standards are common in the U.S., relying on STC (sound transmission class) ratings to assess the noise reduction performance of soundproofing technologies.
How to Choose the Right Soundproofing Manufacturer
The soundproofing industry is competitive, with many manufacturers and suppliers seeking your business. How can you identify reliable companies? Start by using a reputable directory like this one, which filters trustworthy companies. After browsing the list of recommended suppliers above, visit their websites to compare their offerings. Narrow your choices to three or four companies that best fit your needs. Prepare your specifications and questions, then contact each company. Evaluate their responses carefully, focusing on production lead times, delivery options, pricing, and customer service. Excellent customer service is crucial鈥攃hoose a company willing to collaborate and deliver the best results, not just the lowest price.
Soundproofing Terms
- A-Weighting
- The filtering system in a sound meter that allows the meter to disregard lower frequency.
- Absorption Coefficient
- The ratio of the sound absorbed to the sound incident on the material or device.
- Acoustical Analysis
- A determination of the level of reverberation or reflected sound in the space for which the building materials are a factor. Acoustical analyses also determine how much acoustical absorption is needed to reduce reverberation and unwanted noise.
- Acoustical Material
- The material used to change a sound field by absorbing, damping or blocking acoustical energy.
- Acoustics
- The science of sound, which includes its creation, transmission and effects.
- Airborne Noise
- The uninterrupted transmission of noise into the atmosphere. Airborne noise can be controlled by absorption or by being blocked.
- Ambient Noise
- The sounds within a given environment from many different sources.
- Anechoic Room
- A test chamber lined with absorbent acoustical material used to eliminate sound reflections and to determine the sound radiation characteristics of equipment.
- Bel
- A unit of measurement referring to sound intensity. One bel equals 10 decibels.
- Damping
- The process of dissipating mechanical vibratory energy into heat. Damping materials are used to apply to vibrating surfaces in order to reduce the noise radiating from that surface.
- Decay Rate
- The rate at which sound will fade when the noise source is removed, expressed in dB/sec.
- Decibel (dB)
- A unit of measurement referring to sound intensity that is equal to one tenth of a Bel.
- Dissipative Silencer
- A device inserted into air ducts or openings that reduces the noise transmitted through the ducts or openings. Noise reduction is accomplished by using internal sound absorbing materials.
- Flanking
- The pathway along which sound travels around the perimeter or through holes within partitions or barriers erected to reduce the sound isolation between areas. Examples of flanking paths include ductwork, piping, back-to-back electrical boxes within partitions, window mullions, etc.
- Free Field
- Sound from an outdoor source where no obstructions exist.
- Hearing Threshold (HTL Level)
- Amount in decibels that a specified signal can exceed to cause damage to the ears of a listener.
- Hertz (Hz)
- Sound frequency expressed by cycles per second.
- Insertion Loss
- The reduction of sound power levels reached by inserting a muffler or silencer in an acoustic transmission system.
- Live End/Dead End
- An acoustical treatment plan for enclosed areas in which one end is highly absorbent while the other is reflective and diffusive.
- Loudness
- The strength of the physical resonance of a sound to sound pressure and intensity, as experienced by a listener.
- Noise
- A term referring to a sound of any kind, usually in reference to unintelligible or unwanted sound.
- Noise Criteria (NC)
- Sometimes referred to as "dBA levels," it is used to assess listening conditions at ear level by gauging sound levels at loudest locations in a room.
- Octave Band (OB)
- A range of frequencies where the highest frequency of the band is double the lowest frefquency of the band.
- Radiation
- The process in which structure-borne vibrations are converted into airborne sound.
- Reverberation
- Sound waves that continue to bounce off surfaces after the source ends, until the sound waves lose energy and eventually die out.
- Reverberation Room
- A test chamber designed so that the reverberant sound field within the room has an intensity that should be the same in every direction and at every point. It is often used to measure transmission loss and sound absorption.
- Sabin
- The unit of measure used for sound absorption consisting of the number of square feet of sound absorbing material multiplied by the material absorption coefficient.
- Septum
- A thin layer of material sandwiched between two layers of absorptive material that prevents sound waves from passing through the absorptive material.
- Sound
- Pressure waves traveling through the air or in other elastic materials.
- Sound Absorption
- The acoustical process in which sound energy is dispelled as heat rather than reflected back to the environment as sound.
- Sound Level Meter
- An instrument used to measure sound pressure levels. Type 1 are precision instruments, whereas Type 2 are general purpose instruments.
- Sound Power Level (Lw)
- A measure of the total airborne acoustic power created by any noise source; it is expressed on a decibel scale referenced to a usual standard of 10-12 watts.
- Sound Pressure Level (Lp)
- A measure of air pressure changes caused by a sound wave and expressed on a decibel scale referenced to 20µPa.
- Soundproofing
- Creating an area insulated against noise.
- Structure Borne Noise
- The transmission of energy from vibrating structures or solids into noise.
- Vibrations
- Like those with structure borne noise, they are the wavering of a boundary that defines the motion of a mechanical system and can be reduced by isolators or damping.
- Volume
- Cubic area of a space calculated by the length x width x height of the space. Volume influences reverberation time.
- Wavelength
- Wavelike compressions and rarefaction produced by sound passing through air. Sound waves vary with frequency.