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just installed a magnaflow catback dual rear exit on my 04 Sierra and I love the sound but my wife finds it a little loud...any way to tone it down a little?
Is your wife bothered by the noise level, or the tone? Something as simple as an exhaust tip can change the exhaust sound. Many years ago, before my studies in acoustics, I was amazed by the change when I temporarily removed the big rectangular tips from my 'Vette's OE exhaust. Without the big tips, the 454 sounded like a punk, and with them it sounded like we think a 'Vette should sound. The big tips were ugly, but they worked as the designers had intended.
Remember, each component of the exhaust system has its own resonance. The longer the tailpipe, the greater its chance to un-muffle the exhaust as it tries to attain its resonance. That's why designers place the mufflers as far to the rear as possible (Or, turn the tailpipe out the side). To be quiet, big old school (pre-cat) rides often had the can far forward and a second one at the rear. You can't change the tailpipe's natural frequency without changing something about it. With your rear exit cat back, you're violating the "quiet" basics.
Before you start adding a mid-stream resonator, you might consider starting with the tailpipe tips. Even how far up the pipe you place the them will cause a subtle change. Can you spell T-R-O-M-B-O-N-E? I'm assuming your Magnaflow cat back has the long clamp-on stainless tips. You can start by experimenting with their placement.
FYI: Here's a relevant article Exhaust_Tips_and_Tricks
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