APR Licenses New Exhaust Technology

apr tuned APR Licenses New Exhaust Technology APR, LLC. announces successful licensing of a new exhaust technology, RSC™, Reflective Sound Cancellation, to further enhance APR’s line of performance exhaust systems for Volkswagen and Audi vehicles.

Reflective Sound Cancellation allows for maximum exhaust gas flow while completely eliminating in cabin sound resonance (drone). RSC™ incorporates innovative technologies developed in conjunction with NASA. With limited use of packing materials and no baffles, RSC™ allows for a completely straight and free flowing exhaust path through the RSC™ mufflers. Reflective Cancellation bounces the undesirable sound waves into each other to attenuate the wave and completely eliminate the low frequency tones that create drone. Each RSC™ muffler is tuned to eliminate specific, undesirable sound frequencies allowing only the engine’s desirable exhaust notes to be heard and improving performance.

The first APR application to feature RSC™ technology is the New MK5 GTi 2.0T FSI RSC™ Performance Exhaust System. Benefits of the new technology allow APR’s RSC™ Exhaust Systems to meet the European Union and other countries’ noise requirements of 90db or less in new car exhaust sound and even increase performance over traditional performance exhaust systems.

APR will debut RSC™ Exhaust Technology July 19th and 20th at Waterfest 14 with APR’s MK5 GTi 2.0T FSI RSC™ Performance Exhaust System available for retail purchase for the first time.


The following data were measured from a 2008 Volkswagen GTI 2.0T FSI at a 70 MPH constant speed cruise. Sound measurements are made inside the vehicle and recorded as sound pressure level (SPL) in decibels. Comparisons show the resulting sound levels tested with no mufflers, with a competitor’s exhaust system, and the new APR RSC Performance Exhaust system.

rsc drone chart APR Licenses New Exhaust Technology

Many of the competing exhaust systems do not significantly reduce the low frequency tones that occur around 50 to 200 Hz, which makes the tone levels closer to running without a muffler (red bar). It’s these frequency tones that are responsible for “drone”. RSC acoustic prediction methods and design techniques reduce these tones without compromising the sporty sound we all enjoy from high performance automobiles.

The green bars show data taken from the GTI with a competitor’s exhaust system installed. The black bars compare results from the APR RSC™ Performance Exhaust system. The dominant low frequency tone responsible for drone occurs at 94 Hz and has been significantly reduced with the APR RSC™ Performance Exhaust system by about 20 dB compared to the competitor’s exhaust system.

The following graph illustrates the narrowband acoustic spectra for the competitor’s exhaust system and the APR RSC™ Performance Exhaust system. Both the dominant tones and the broadband sound levels are quieter for the APR RSC™ system over most of the frequency range, especially around 94 Hz where drone notes dominate.

rsc spl chart APR Licenses New Exhaust Technology

RSC™ technology provides sound levels comparable or even quieter than OEM exhaust systems at cruising speed. RSC’s™ straight through design minimizes back pressure and provides gains greater than other performance exhaust systems. The example shown for the Volkswagen GTI demonstrates the ability to tailor the sound spectra to eliminate drone while maintaining a sporty sound, especially under full throttle.

For a complete explanation of RSC™ technology and information regarding future APR RSC exhaust applications please visit www.goapr.com.

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