Quote:
Originally Posted by 1990 quasar blue
With the Corsa system is it the resonator that reduces the drone? I ask because it is straight through. I thought what really helped the Corsa be drone free was the fact that they only flow through one pipe in the mufflers....*
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If you look closely at the Corsa Resonator (specifically) you'll see a circular slot opening in the pipe section near the front of each of the resonator pipes. Like blowing air over the top of a pop bottle, a resonance is generated, dependent on the internal dimensions of the resonator - not unlike a pipe organ.
As it happens, the wave pulses created within the resonator cancel those exhaust pulses of the same frequency - and it occurs at that slot in the through pipe you see in the resonator.
And, IIRC, the mufflers too have (Helmholtz) resonators in them; shorter than the those in the resonator; designed to address the resonance occurring around 34K RPM.
Google "Helmholtz Resonator" for an in depth reading and how it is used for noise cancellation.