
Opelika, AL, July 14, 2008- 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 MKV 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 MKV GTI 2.0T FSI RSC
Performance Exhaust System available for retail purchase for
the first time.
MKV VW GTI 2.0T FSI
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.
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 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.
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