As we know it’s (probably most) important for subwoofers to have isolation between front and back side of the speaker.
When I increase the bass setting in the equalizer I mostly get louder annoying midbass but doesn’t get much deeper.
Then went to take a look at the back shelf. In just 30 seconds saw that there are 3 clips holding the top lining inside the trunk at the subwoofer.

Undid the clips and the lining came off.
then saw 3 big holes in the metal shelf from the said clips.
Patched the holes with 3 small patches of dynomat thing. (Any cheaper brand ok)


now when I closed the clips back the clips made a hole through the insulation material and closed nice and tight.
back to the car turned in the music and now when I increase the bass from eq the bass gets deep like never before. I can feel it, before only could hear it mostly.
worth it.

 

My '13 doesn't even have that trunk lining (the metal is exposed on that underside on the '13s). Nice discovery!

 

Also after a few days added a circle of weatherproof tape around the subwoofer to make a seal between the metal shelf and the lining. To further insulate the front wave from the back wave of the sub.

 

Maybe these pics are more clear?





I tried it, and honestly didn't noticed too huge a difference. Then again maybe it's my music? Lots of bass-heavy stuff (Lately a lot of Deichkind).

I'll seal around the sub another day though, maybe that'll help a bit.

 

There is improvement with mine. My seats and jacket didn’t vibrate from the music before. The stuff that I put on seems thicker , maybe add a couple of layers.
Try increasing the eq and see it should get also deeper not just louder like before.

 

What I made there were patches over the holes. It's 3-4mm thick bubble wrap with a layer of Nashua rubber all weather tape.

 

I had this kilmat sound deadening left (got the smallest box for $25) from when I did the doors, maybe its a special material that should be used because it doesn’t flex or vibrate. From the point of view of isolating front air from back anything should work, but maybe to isolate the waves there is more to it and needs the sound deadening. Don’t know. To make it rigid maybe add more layers of that sticky tar tape. And it’s better to put it directly to metal without the other bubble tape material.

 

There's not going to be a huge difference between what I've done and what kill mat will provide. Mainly what's needed is to try to seal the holes as best possible (if you have to make some holes for the mounting clips to hold the panel, you're pretty must negating any perfect seal there.

Basically the best result will be a nearly-sealed box... but I think the volume is a smidge more than what that sub needs anyways. So even if we're perfect it would be negligible compared to what we've done.

I'll say though there's a dead-spot for bass being fed up front and to the rear if you adjust your fader to about 3clicks towards the back. It's kinda crap honestly and I don't understand why.

 

For me when I got the car I had a issue that I could locate (hear) that bass is coming from the rear shelf and not blended as part of the music scene. For that I installed sound deadening on the front doors which made the front doors have more bass and it helped bass blend in the picture and pull the bass to the front. The setting for my fader is unchanged, in middle.

 

For the weather tape gasket from home depot I got the firm one, but there was also a medium-soft one. Softer one would be better for taking the shape of the lining.

 

Good idea on the Dynamat in that area. I used felt Tesa tape in those three holes, as I did notice the liner would rattle (because of the extra space between the clips). But, Dynamat (or Siless black in my case) might fill in the area a little better.

 

Wow, you all are very particular about your music sound. Not a bad thing, but right now, I am just happy that my ML system has been working when I get in the car. Thought I had a busted amp as the sound just went out one day. Then it went back on. Then it went out. Now back on since Thanksgiving. So I am not touching a thing related to the radio and speakers. Keeping the good vibes and gremlins away.

 

Maybe some water got in trunk where the amp is or what would be the the reason?

 

I put sound dampening material all over that underside and it made a huge difference.

 

mine is the same- no lining. Going to check this out tomorrow and fill any holes! Also tossing up whether to get a replacement sub to fit on the shelf. Not sure what one to get yet!