Hello, I just purchased a 2015 ML350 and noticed the subwoofer sounded like it was blown and I was getting ready to pay someone to replace the subwoofer - BUT I solved the issue without spending money. (Just try this method before replacing the subwoofer)

Here was my issue:

Symptoms: You're playing music and you hear the subwoofer in the rear trunk area making a terrible "BONG BONG" sounds similar to a blown speaker (during certain bass under tones during a song) - I figured out that the subwoofer is blaring the bass against the inner wheel well and there is not enough insulation to "absorb" the bass.

The fix: No tools needed - Open your trunk - locate the small door on the left side of your trunk that is covering your subwoofer. If you look inside you notice that the subwoofer is very close to the body of the car - which makes the sound bounce off the metal - making a terrible sound during songs with high bass. Stuff that area deeply with towels or socks (using it as a form of insulation between the subwoofer unit and the body of the car)

My speaker system sounds new again ever since. I love my ML350 but now i'm off to solve some interior rattle issues.

 

Interesting and clever solution, thanks for sharing.

 

no problem good sir