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      12-13-2019, 02:45 AM   #99
benro2
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Drives: '18 440i Coupe, 09 Audi S5
Join Date: Nov 2013
Location: Sydney, Australia

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Quote:
Originally Posted by ntg44 View Post
3500 RPM rasp is still there. I can't figure it out. But I've also gone through 2 revisions of mufflers and I haven't driven as many miles as you have. It's not that bad though, and is easily manageable with throttle.
Have you looked into Helmholtz chambers/resonators? You can tune these to remove a specific range of frequencies. Might be the last little thing you need to perfect the sound? Even better, you can add as many as you need, tuned to different frequency ranges, say if there's a bit of a boom/drone - should be able to completely remove it!
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