Noise levels associated with diesel generators often exceed local codes and city ordinances, not to mention personal comfort levels making noise control a necessity. In many cases, an engine exhaust muffler is the only form of noise control utilized in an attempt to quiet the engine. However, engine exhaust is only one small component of the overall noise caused by the generator system. Noise propagates from the engine, generator, radiator fan, turbocharger and even from the muffler casing. Numerous problems also arise when a large generator must be mobile. North American Power and Controls is a company known in the industry as a "generator packager." NAP&C brings together and assembles all the components that make up a generator system including the engine, generator, fuel system, enclosure, controls, ventilation, acoustics and, in this case, transport. One of NAP&C's customer's is Pacific Bell, a regional telecommunications company, which uses standby power supply systems for their switching facilities. The need arose for a portable generator to be used to maintain power while the primary building power was down for construction or in an emergency power outage. The generator needed to be both mobile and quiet since it would often be used near commercial or residential areas. As a frequent and satisfied customer of Ruskin Sound Control, NAP&C turned to Ruskin for a solution to their portable generator problem. Working closely with Ruskin engineers, a design, capable of meeting and exceeding the end customers' performance requirements, was engineered and a final design was approved. Ruskin 2" thick acoustical panels were chosen for the enclosure walls and roof. Due to the dynamic nature of placing an engine in a housing mounted on a trailer the design team was faced with several problems not the least of which was the acoustical attenuation requirements. Weight and strength constraints were the most limiting and acoustics became a secondary concern. However, based on manufacturer's sound power ratings for the un-enclosed generator compared to acoustical measurements taken in the field using the Ruskin enclosure under actual operating conditions sound levels were decreased significantly.