Motorhome Acoustical Issues: An Overview

Motorhomes or recreational vehicles (RV's) are unique vehicles in that they pose many interesting design challenges to acoustical engineers. This type of vehicle has many of the typical NVH (Noise Vibration and Harshness) issues seen in passenger cars and heavy trucks; however, there is an entire arena of NVH issues that are not seen in these other products. The issues are not present in these other markets; because a motorhome, not only serves as a means of transportation, it also serves in a secondary role as a home. The dual role of the coach creates many residential noise concerns. Some of these issues include managing generator sound levels while the coach is either parked in a campsite or on road, controlling engine noise levels for designs where the bed serves as the engine cover, and controlling wind noise to improve speech communication between the driver and passengers. Complicating these issues is the fact that each unit is semi-customized. In many cases the owner also has a choice of chassis, generator, engine and drivetrain along with appliances and other amenities that affect the acoustics. With the high cost of these vehicles, owners demand low noise levels and high sound quality in all aspects of vehicle operation. This paper presents an overview of numerous Class A motorhome sound quality studies and presents typical sound levels and techniques for controlling undesirable sounds.