Sound blockers are a type of acoustic insulation that blocks sound, an audible but invisible form of energy that travels  through the air as a wave. Sound blockers are made of dense materials and are placed between the source of the sound and its receiver. Ideally, noise blockers should be as installed as close as possible to the source, such as in an engine bay. The next best location is near the receiver, such as the driver in a mobile equipment cabin.    

If you’re wondering whether sound blockers are right for your industrial noise control application, keep reading to find answers to these questions.

  • How do noise barriers work?
  • Which types are available?
  • What questions do I need to ask about the application?
  • How are sound blocking products made?

Elasto Proxy fabricates noise barriers for the mobile equipment industry and can also help you to find noise control solutions for machine enclosures, such as with gensets. If you need custom acoustic insulation like this, contact us.  

How Do Sound Blockers Work

Sound barriers work by diffracting the sound that is transmitted from the source to the receiver. Because sound is a wave, it bends (diffracts) when encountering an obstacle. When a sound barrier blocks the line-of-sight between the source and receiver, the Fresnel Number (N) can be calculated. This dimensionless number can be used to chart attenuation, the gradual loss of the sound’s intensity through noise barriers.   

Sound blockers need to block any and all paths from the source to the receiver. Because sound travels the same path as air, even tiny gaps that admit air will also permit the passage of noise. Sound barriers are also affected by varying air speeds. An airflow that travels from the source to the receiver may diffract sound passing through the air and cause it to bend downward, allowing it to be heard.

Types of Sound Blocking Materials

Sound blockers are usually made of  vinyl, a dense but flexible plastic that also offers strength, durability, and resistance to moisture and humidity. Mass loaded vinyl (MLV), a type of vinyl, is often used because it contains salt, sand, or tiny metal particles for added mass with minimal thickness. This added mass helps to block the sound. MLV’s flexibility supports loading when an external force, such as pressing or bending, is applied. MLV’s relative thinness also supports effective acoustic insulation in tight spaces.

Mass loaded vinyl can be used as a standalone sound blocking material or in conjunction with sound absorbing or sound dampening materials. Although MLV provides good environmental resistance, it is important to remember that other types of acoustic insulation may have different material properties. Therefore, a sound barrier that’s suitable for a factory office may not be able to withstand the splash of automotive fluids in an engine bay, or the petroleum products used with machinery and equipment.

How Sound Blockers Are Made  

Sound blockers are supplied as sheets or rolls in various lengths, widths, and thicknesses. Using water jet cutting, Elasto Proxy converts these materials to size without the tooling costs associated with die cutting. Compared to manual cutting with utility knives, rubber water jet cutting is faster and more precise. The precision that water jet technology provides helps to prevent the creation of sound-permitting air gaps that can result when sound blocking materials with poor-quality cuts don’t conform with product features.  

Elasto Proxy can also combine materials together to create an acoustic insulation “sandwich” with the specific properties that you need. For example, at our manufacturing center near Montreal, Canada, we can laminate sound blockers to foams and facings that provide sound absorption and sound dampening. Melamine, a sound absorbing foam, is often used because it’s flexible and lightweight. Facings can provide frequency attenuation, chemical or abrasion resistance, decoration, or support for cleaning.

Sound blockers from Elasto Proxy can sandwich the barrier material between a decoupler and a layer of acoustic foam. Decoupling, the mechanical separation, of two sides of a structure, causes the sound barrier and the acoustic foam to vibration independently of each other for effective sound isolation. Elasto Proxy can also apply a pressure-sensitive adhesive (PSA) tape with a removable liner for installation.

Ten Questions to Ask During Sound Blocker Selection

During acoustic insulation design, engineers need to ask and answer a series of questions. Elasto Proxy can help. Each application is different, but this list is a good place to start.

  1. What is the source of the sound?
  2. How close to the source of the sound can you install the sound blocker?
  3. Do you need sound blocking plus sound absorption and/or vibration dampening?
  4. Is airflow a factor?
  5. What is the maximum insulation thickness that your application can support?
  6. Do you need resistance to media such as fuels, chemicals, or cleaners?
  7. Do you need resistance to a specific range of temperatures?
  8. Does your application require flame resistance?
  9. Do you need acoustic insulation that meets a specific standard, such as Class 1 fire rating?
  10. How will you install the installation?

Sound Blocker Products You Can Order Now

Elasto Proxy fabricates standard and custom acoustic insulation for industrial noise control. You can install our sound blocking products on walls, ceilings, or floors; around pipes or HVAC ducts; or within machine enclosures, mechanical rooms, or mobile equipment. For acoustic insulation samples that you can see for yourself and hold in your hands, ask for the Elasto Bag.

This sackful of samples from Elasto Proxy includes FM-500-60-ZM flooring, a single layer of acoustical foam that’s bonded to a sound barrier. The top of insulation sandwich features a durable, wear resistance, diamond plate design. Applications for FM-500-60-ZM include floormats and flooring in both on-road and off-road equipment. It’s also a good choice for runner and anti-fatigue mats.    

Ready to learn more? Request the Elasto Bag.