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his Sound BarrierMLV-FAQs page is our attempt to dispel any fiction about Mass Loaded Vinyl (MLV) and give you the facts in a FAQ format.

Mass Loaded Vinyl is the material of choice for use as a sound barrier. There are numerous brand names of MLV being sold by numerous companies, who each have various claims, only some of which are true. This application note provides some background on MLV, describes how it works from a technical standpoint, examines some of the claims, and recommends best practices for using MLV for soundproofing.

What is MLV?-Sound BarrierMLV-FAQs

Mass Loaded Vinyl has been used for soundproofing since at least the 1960s. It is essentially a viscoelastic material, such as polyvinylchloride (PVC, or vinyl), that is loaded with an inert material, such calcium carbonate or barium sulfate. Viscous materials, such as honey, when subjected to a force, will flow and take on a different shape. On the other hand, elastic materials, such as rubber, when subjected to a force will deform and snap back to their original shape. Viscoelastic materials exhibit both behaviors they will flow, but when the force is removed or reversed, they will go back to their original shape. This property, known as hysteresis (or damping), contributes to the ability of MLV to attenuate sound. It is the mechanism by which many companies claim that MLV converts sound to heat, although it is not the fundamental means by which MLV attenuates sound.

onic-Fiber mineral wool is one of our most popular and effective soundproofing products. Acting as a sound absorption material Sonic-Fiber mineral wool is used in all of our acoustical panels whether they are hard sided or soft sided. Since we use acoustical panels in almost all of our soundproof enclosures, Sonic-Fiber wool shows up in our soundproofing solutions over and over again in many different product forms.

Whenever residential, commercial, industrial or transportation noise problems call for sound absorption, we look to our mineral wool as our first line of defense against unwanted noise. Easy to handle and relatively lightweight, Sonic-Fiber is a semi-flexible non-asbestos mineral wool that provides greater sound attenuation than fiberglass bats or urethane foam.

Sonic-Fiber is naturally hydrophobic (repels water), fire resistant, does not promote mold growth, and is vermin-proof. It is available in sheets that are either un-faced or faced on one side with an encapsulant which protects the fibers and acts like a vapor barrier. Sonic-Fiber comes in standard size sheets of 4 x 6 with a 2 thickness, and a density of 8 lbscu-ft. Mechanical and acoustic properties are provided below.

The Noise Reduction Coefficient (NRC) of a material is obtained through testing by a certified laboratory to ASTM standards. The NRC is an indication of the amount of sound energy absorbed upon striking a particular surface. An NRC of 0 indicates perfect reflection (such as a smooth concrete surface) and an NRC of 1 indicates perfect absorption. Sonic-Fiber is used inside rooms, enclosures and walls to significantly reduce acoustical reflections and overall sound energy, and may be used together with sound barrier materials, such as Sonic-Shield Noise Barrier.

Sonic-Fiber Mineral Wool 10-2016

Sonic-Shield has developed a patent-pending modular sound dampening acoustical curtain, Sonic-Curtain, consisting of our 1 lbsf Sonic-Shield reinforced sound barrier material together with our 2 thick Sonic-Fiber sound absorption material.


Acoustical Curtains deliver the performance of acoustical panels in many applications
This combination provides outstanding soundproofing capabilities (26 STC, 1.0 NRC) in a durable, attractive and easy-to-use package. We believe that Sonic-Curtains offer a better alternative to the typical quilted acoustic blankets, which have limited abilities to block and absorb sound. The Sonic-Curtain is modular. The sound barrier material backing can come in lengths of up to 30 feet, and the sound absorbing Sonic-Fiber can simply be attached anywhere along the length using a Velcro fastening system. The Sonic-Fiber is encapsulated in a high-quality fire retardant fabric, and is available in a wide variety of colors and textures. Both the encapsulated Sonic-Fiber absorption material and Sonic-Shield barrier materials are water resistant, enabling them to be used outdoors or to be washed, if needed. The fabric can also be screen-printed with custom artwork and logos.

Sound Absorber FAQs are presented to help you understand the different types of products available and their effectiveness.

A variety of materials are used for sound absorption, each with different claims of effectiveness. This application note provides some background on sound absorption materials, describes from a technical standpoint how it works, examines some of the claims, and recommends best practices for using these materials for soundproofing.

What is a sound absorber?-Sound Absorber FAQs

A sound absorber is any material that inhibits the reflection of sound and can transform or dissipate acoustical energy. Sound absorbers can take various forms, from everyday materials found in homes and offices, such as carpets, drapes, wall coverings and acoustical ceilings, to more specialized materials found in commercial and industrial applications, such as acoustical panels, fibers, foams and fabrics. Generally, the specialized sound absorption materials will have a greater ability to absorb sound, as measured by the materials Noise Reduction Coefficient, or NRC (see our application note on on Acoustical Terms and Concepts Used in Soundproofing).

How do sound absorbers work?-Sound Absorber FAQs

Sound absorbers are typically foam sheets or fiber mats that attenuate sound by converting acoustical energy into thermal energy. If the surface of a material is nonporous, such as smooth concrete, acoustical energy will reflect off of the surface with little loss of acoustical energy. If the surface is porous, such as a fiber batting, acoustical energy will penetrate the surface and scatter among the pores and interact and reflect off of the fibers. Scattering among the fibers and pores results in frictional losses resulting in conversion of the acoustical energy into heat and the attenuation of noise. As the pore size decreases, less acoustical energy is transferred into the material and more is reflected back into the environment. As the pore size increases, more acoustical energy can penetrate into the material, however, if the pore size is too large, acoustical energy will pass through the material with very little attenuation. The ideal sound absorber material must therefore have an optimum pore size and density to most efficiently convert acoustical energy into thermal energy.

Are foams effective sound absorbers?-Sound Absorber FAQs

Foams are typically polyurethane materials with a large number of gas bubbles or voids, and are classified in either the closed-cell or open-cell varieties. Closed-cell foams have material around each individual bubble or pore, that do not permit airborne sound to pass between pores. As a result, closed-cell foams are not effective sound absorbers because the acoustical energy reflects off of the outer surface of the pores. These materials, do, however, make for good vibration absorbers. Open-cell foams contain pores that interconnect without barriers between them, and are more commonly used for sound absorption. Generally, open-cell foams with small pore sizes make for more effective sound absorbers than those with larger pore sizes. Many manufacturers of open-cell foams configure the sheets with an egg carton facing, which are marginally better at diffusing sound, however, the depth of the egg cartons is not sufficient to attenuate low frequency noise. Some manufacturers use a smooth facing on the surface of the foam, and these should be avoided since the smooth surface may reflect sound.

What about spray-on foams?-Sound Absorber FAQs

Spray-on polyurethane foams are typically used for thermal insulation to fill gaps in joints and cracks in walls. These foams are effective (to a certain extent) in blocking noise flanking paths, however, they are not effective for use as sound absorber materials. This is due to the fact that the foams will typically expand and harden, and will not have adequate compliance to attenuate sound. Furthermore, if used between walls, the foams will displace the air gap between the walls and provide a short circuit path of relatively stiff material that will more readily transmit sound from one side of the wall to the other.

Other types of spray-on foams are used on large exposed surfaces, such as metal ceilings in commercial and industrial spaces, which are not effective sound absorbers, although they have other properties that may be beneficial for soundproofing. These foams typically contain particles or materials that provide a rough texture to the surface, that tends to diffuse acoustical energy that is, planar acoustical waves do not reflect off of the surface in a planar manner, and spread out in several directions. Although they do not reduce the overall acoustical energy, there will be a slight benefit in reducing the amount of acoustical reverberation within the room. The foam also provides mass and damping to the surfaces they coat, deadening potential structural vibrations.

onic-Fiber Faced Mineral Wool is a semi-flexible non-asbestos mineral wool that provides greater sound attenuation than fiberglass bats or urethane foam. Sonic-Fiber Faced Mineral Wool is naturally hydrophobic (repels water), fire resistant, does not promote mold growth, and is vermin-proof. ( yes vermin proof- we are not kidding- if it wasnt important, we wouldnt bring it up!)

It is available in sheets that are faced on one side with an encapsulant which protects the fibers and acts like a vapor barrier. The facing materials are available in white or black and if appearance is important to you, we can work with you on the color of the facing material. Since Sonic-Fiber Faced Mineral Wool is generally used as a component of an enclosure, an acoustical panel the color of the facing material generally does not matter. However, a foil facing is available and we can speak with you about the need for that particular flavor of Sonic-Fiber

The Noise Reduction Coefficient (NRC) of a material is obtained through testing by a certified laboratory to ASTM standards. The NRC is an indication of the amount of sound energy absorbed upon striking a particular surface. An NRC of 0 indicates perfect reflection (such as a smooth concrete surface) and an NRC of 1 indicates perfect absorption. Sonic-Fiber Faced Mineral Wool is used inside rooms, enclosures and walls to reduce acoustical reflections and sound energy, is used with sound barrier materials, such as Sonic-Shield Noise Barrier.

Sonic-Shields sound dampening acoustical panels consist of a sheet of Sonic Shield Noise Barrier and Sonic Fiber Noise Absorber to effectively block and absorb unwanted noise.

The resulting panel has a Sound Transmission Class (STC) of 26 and a Noise Reduction Coefficient (NRC) of 1.0, meaning that they are capable of attenuating 26 dB of noise from one side of the panel to the other and that they are also capable of completely absorbing noise. This results in a panel with outstanding sound reduction abilities.


Sonic-Shield soft sided panels
Our panels are generally used in industrial or commercial settings, where generators, pumps, motors, chillers, transformers, and other large pieces of machinery are the source of the noise. Generally speaking it is more practical to enclose the noise source with acoustical panels than it is to soundproof the area where the affected parties are working or playing. Enclosing the source of the noise with the hard aluminum panels is our most common solution for outdoor noise problems.

Sonic-Shield offers a full range of soundproofing products and develops customized soundproofing solutions to solve even the most demanding noise problems. Our team of acoustic experts can help you pinpoint sources of noise and rapidly develop cost effective solutions to; eliminate, block or absorb the noise.

Sonic-Shield believes that while there may be similarities, no two noise pollution problems are exactly alike. Accordingly, our soundproofing solutions reflect our ability to identify, and when necessary, develop and fabricate the appropriate soundproofing materials for your particular needs. Sonic-Shield explains sound absorption vs. sound barriers as part of our solution finding process.

Whether you have a problem requiring an immediate solution or have the luxury of planning for a problem that will exist in the future, inside or outside, we would like to discuss your noise or vibration problem with you.

Sonic-Shield explains sound absorption vs. sound barriers over and over again because most of our customized solutions use one of two families of products: sound barriers andor sound absorption materials.

Sonic-Shield Noise Barrier Mass Loaded Vinyl is a flexible visco-elastic polymer that reduces the transmission of noise through walls, panels, partitions and enclosures. It wont shrink, rot or cause metal corrosion and also features a strong resistance to adverse environmental conditions, oils, some acids and alkalis. Furthermore, Sonic-Shield Noise Barrier Mass Loaded Vinyl does not contain hazardous materials, lead or other heavy metals.

The Sound Transmission Class (STC) is obtained through testing by a certified laboratory to ASTM standards. The STC describes how well the material attenuates airborne sound, and is generally related to the amount of noise that the material is capable of attenuating. For example, a typical wall in a residential house has an STC of 33, meaning that it can attenuate 33 dB from one side of the wall to the other. The addition of Sonic-Shield to the wall can significantly increase the STC to over 50. Additional noise reduction can be obtained by using Sonic-Shield Noise Barrier with a sound absorbing material, such as Sonic-Fiber.

Sonic-Shield Noise Barrier mass loaded vinyl is also available with a reinforced aluminum foil facing, which gives it a UL Class A fire rating per ASTM E-84, Surface Burning Characteristics of Building Materials. Class A is the highest degree of fire resistance, which means that it resists the penetration of fire as a result of a standard fire exposure. We recommend use of Class A Sonic-Shield Noise Barrier mass loaded vinyl in applications where fire resistance is required by building codes, including walls, doors, roofs, attics, elevators, equipment rooms, etc. Other applications that may require Class A materials include high temperature applications, such as HVAC duct liners and engine compartments.

What is the difference between your product and other mass loaded vinyls on the market?

There is no basic difference except for the company telling you how to use and install the product. Pay attention to the word INSTALL. Correct installation is critical to this product working the way it is designed to work. There are over 100 companies in the U.S. selling the same basic product, made by a very small group of resin extruders. The product is made from resin pellets that are melted and extruded into massively long sheets of flexible vinyl material and then cut into sheets and rolled and shipped to distributors. We do not make Sonic-Shield Noise Barrier Mass Loaded Vinyl, we buy it and put our own label on it.

Why does everyone sell a Mass Loaded Vinyl and why are all the names different when the pictures look the same?

Different companies will try to convince you that they have a proprietary formula that makes THEIR MLV better than any other on the market. We could list the brands of MLV on the market today, including our own, and the rest of this page will be filled with nothing but names. Think of MLV like bottled water. Aquafina (Pepsi) and Dasani (Coca-Cola) have their own brands of bottled water. Nestle, owns an entire family of bottled water brands all over the country- see below- look familiar?

Soundproof enclosures are frequently a great solution for noise problems. Below is a case study as well as pictures of soundproof enclosures from different client assignments using acoustical panels to provide a soundproofing solution.

Stringent community noise ordinances did not permit the acceptance of a containerized diesel power generator set which was installed by a major hospital. Community noise ordinances required that the generator could not increase noise levels by more than 10 dB higher than the ambient sound levels measured at the property line of the facility. Since ambient noise measured 50 dBA, the generator would need to emit no more than 65 dBA from a distance of about 20 feet. Prior tests indicated that the generator emitted more than 80 dBA of noise, requiring more than 15 dB of noise reduction, or a 65% reduction of perceived loudness level.

Sonic-Shield engineers visited the site, took acoustical and physical measurements, and examined the design of the existing generator enclosure. This review identified several areas where sound was escaping from the generator enclosure, through either leaks in the container or use of inadequate sound proofing materials. Several opportunities were identified to further reduce the noise, including the use of additional sound absorption beneath the container floor, acoustical close-out panels along container support structure, larger and more effective noise dampening baffles, and additional high-quality acoustical materials on the inside of the container. These recommendations were further complicated by the fact that the footprint or appearance of the container could not be altered from its as-delivered state.

Within two days, the required improvements were implemented on the container, resulting in a decrease in noise levels from over 80 dBA to about 64 dBA, which represents a 69% reduction in perceived noise levels. Sound levels measured at the property line found that the generator increased noise levels by only 8 dB more than the ambient noise, which enabled the hospital to easily comply with community noise ordinances.

Soundproof enclosures take many forms and sizes. Below are pictures of soundproof enclosures built around a motor.