Posted on: February 23rd, 2017 by Alex Wills

When Every Sound Counts

The whole purpose of sound reduction on specialty vehicles is to let the vehicle do what it’s supposed to do. Excess noise can be problematic and even dangerous, depending on the type of vehicle. For a media van, noise can degrade production value. On board an ambulance, it can cost a life. No matter what type of work your vehicles are designed to do, they can do it better with less noise.emergency

The first step in developing a sound reduction program is to understand when quiet operation is most important. If a vehicle will be doing most of its work when parked (such as a media van) ambient noise and, when so equipped, generator noise will be the dominant sources. Other vehicles will need to be quiet as they travel over the road (an ambulance).

In the case of vehicles that need to be quiet at rest, Soundown offers a number of treatment options. One basic but highly effective treatment is to install Soundown’s Vinyl/Foam Composite insulation between the exterior skin and the interior panels. For vehicles with very stringent noise requirements, Soundown’s QuietCore composite plywood can be used for the interior paneling. And when the most extreme noise requirements must be met, these panels can be isolated from the shell of the vehicle using our specialty elastomer Sylomer.

Many specialty vehicles are outfitted with generators in order to function as needed. When present, generators are the dominant noise source and can be difficult to treat. For a quiet installation, good planning is essential and includes making a well-sealed compartment with sufficient room for 2” or even 3” of Soundown’s Vinyl/Foam Composite. It’s also important to allow for a secondary vibration isolation mount, such as Soundown’s Ring Bushings. These should be installed under the pan, in addition to whatever mounts are supplied with the generator. They also should land directly on the frame, or on another heavy structure that is tied to the frame.

For vehicles that need to be quiet while driving, the primary noise sources are engine/drive train and road noise. Insulation is typically used for engine noise, while vibration damping treatments are often the most effective for road noise. The treatment areas for insulating against engine noise are typically the surfaces of the engine bay that are common to the cab. Soundown’s Vinyl/Foam Composite is highly effective in these areas.

Vibration damping materials used to reduce road noise work by transforming vibrational energy into minute amounts of heat before it can radiate into the space as noise. Soundown’s 1/16” Damping Sheet uses a specialized PVC-based formulation for excellent damping with light panels. The treatment areas should include wheel wells, floors, and the vehicle’s skin (from the floor up to about 3′).

While the treatments outlined above cover a range of common applications and vehicle types, Soundown offers a number of other products that may be applicable to your project. Please call to discuss your noise control goals and we will be happy to help design a custom solution for your vehicle.