Roush Industries in Livonia, MI is a leading supplier of noise and vibration control engineering and consulting services to the auto industry, offering field and laboratory testing as well as acoustic dynamometer testing of vehicles, engines, transmissions, brakes and components. Through our combination of NVH experts, equipment and facilities, Roush is uniquely qualified to provide the highly specialized design, analysis, testing, and engineering services necessary to solve complex noise and vibration issues.

The Roush NVH Chassis Rolls Dynamometer is the centerpiece of our vehicle NVH development services. It is available as a stand alone tool, or in conjunction with measurement equipment, mechanical and engineering support. It provides our OEM and Tier customers an independent facility, allowing them to use their own staff and equipment to perform tests, or to direct a Roush team in the development of their vehicle systems. Additionally, our customers can expect accurate, unbiased results with the security of knowing Roush will protect customer privacy and confidentiality.

Roush’s new high performance Hemi-Anechoic chamber was designed and installed by Eckel Industries and provides the controlled acoustic environment for their NVH consulting services. The 4WD Chassis rolls with Schenck Pegasus Dynamometers and controls incorporates independent dynamometers for front and rear axles to allow 2WD and 4WD operation. The chamber provides Roush with the precision testing environment it needs to make critical measurements for their OEM and tier customers and for development of their vehicle systems.

The chamber utilizes Eckel’s EMW high transparency, 52% open area perforated metallic anechoic wedge lining. The chamber’s performance exceeded the design criteria low frequency cut-off of 100 Hz by a significant margin. This allows Roush engineers make precision measurements to below 80 Hz at the low end of the spectrum to 20,000 Hz at the high end. Qualification of the chamber was done in accordance with ISO 3745. The “inverse square” performance of the chamber (variance from 6dB per doubling of distance) for frequencies from 80 Hz to 20 KHz are shown in the accompanying graph.(fig.1) The chamber achieved a background ambient noise level of NC 14 with 7,000 CFM of ventilation and dyno pumps running.

The interior dimension (free field) of the chamber is 40’ x 23’ x 14’. The chamber walls and ceiling were constructed of concrete and rest on a 12” thick steel reinforced isolated floor. Integrated into the chamber floor is a Schenck Pegasus four wheel, road wheel dynamometer.

The metallic wedge utilizes classic “Harvard design” with two 12” peaks on a 24” x 24” base frame with an overall depth of treatment of 34”. Incorporated into the wedge construction is a “white” acoustically transparent matting between the perforated facing and acoustic fill for positive fiber containment along with uniform color and appearance. The wedge units are factory finished in white enamel and were mounted to the walls and ceiling using a unique track mounting system.

For vehicle access to the chamber two in-swinging wedge “cage doors” and two out-swinging sound doors were provided with a clear opening of 10’ x 10’. The “cage doors” incorporate curved radius wedges at their leading edges that mate when the doors are closed providing full depth of treatment coverage across the entire entry way.

Several unique features were designed by Roush and Eckel engineers into the system including a telescoping dynamometer shaft silencer that completely enclosed the dyno shaft as the road wheel was adjusted for different wheel base vehicles, plus wall surfaces of the dyno pit were lined with functional sound absorbing panels to eliminate reverberation.

Roush has one goal – improving the noise and vibration quality of our customers’ products and these new facilities provide the platform to accomplish this goal.

Sound and Vibration Article (PDF)