Just thought I'd mention this as I found it interesting, I've gutted alot of the interior of my car in order to install a custom stereo. With the backseat/package tray/spare tire cover removed, the bassy resonance from my Magnaflow catback is nearly gone. The car is louder inside as I can now hear the fuel pump and road noise, but that annoying boomy drone that drives me nuts at around 2000 rpm under load is no longer present.


My point is, this aweful drone appears to have a lot to do with the dynamics of the car itself. I'm going to add sound deadener before I reassemble everything as others have done to see what kind of improvement it makes.

Do you have a Pontiac/Holden trunkliner? One member mentioned it offered noticeable sound deadening. I have one but do not have an aftermarket exhaust.

Hmm I was considering one of those, only thing thats a problem for me is I have a sub in the spare tire well. If the liner does offer sound deadening properties then it will also negatively effect the sound from the sub. I have a feeling that the physical properties of the trunk itself contribute alot to this drone everyone gets. I'm curious if people whom have installed stereo enclosures or other things that altered the volume of the trunk space noticed any change in exhaust drone (provided they also have a catback).

Whats happen in my situation, is by removing the backseat and package tray I've greatly increased the volume of the trunk. It appears by doing this, the resonant frequency of the space changed and voila the drone is no longer present. I just thought it was interesting, obviously removing your backseat permenantly isn't any kind of solution.