Rattling from rear seat with subwoofer box

So, I just did my full sound system and to make my story short I basically have installed sound deadening on the lower cab wall and in the actual sub box itself. The box isn’t hitting any metal and it’s nice and snug too. I’m putting up the volume and there’s a loud annoying rattle coming from that back wall I Can’t seem to figure out. I have the automatic rear window idk if it has something to do with that system? Any help would be great thx!

 

Much of the rattle sounds you sometime hear are those vents on the back wall. They are needed, so dont plug them, but you can put soft foam in them that still breaths, but stops the flapping rattling. Otherwise wrap the power window cables with foam tape.

 

I have same issue. Installed JL stealthbox and when i turn it up it rattles bad. Took apart the storage bins and the vent housing are really sloppy fit. I folded up little pieces of cardboard and shoved in between the sheetmetal and the vent housing to shim it so it doesn't wiggle around. Reinstalled sub but not the bins, cranked it up and no rattle. So I installed the storage bins and seats, then tried again and now the bins are rattling. It definitely helped with some of the rattle but not all so I'm gonna get some sound deadening and install on back wall to isolate the plastic bins from the sheetmetal, hoping that should do the trick.

 

Its def the rear window opener.......give it to me. That'll......maybe.....fix your rattle issue.

 

Lol so I kind of figured out what the problem was. After sound deadening pretty everything even the back end of the box. I decided to take out the box and play it outside, sure enough the rattling came from the box itself. The shop that did it for me ordered a box with .70 air space per chamber and my subs required 1.0 air space per chamber. The subs where basically blowing the box and I noticed the back of the box in the center corner flexing almost like it was lose. I couldn’t tell cuz the box has a plastic liner. Long story short, I’m ordering a new box with .55 air spacer per chamber but with 6” mounting depth and installing 10” sundowns SA10s which is perfect cuz these subs require .50 per, so I’ll have a nice setup. One issue I might have is clearance from behind the seat to the sub. But I’m gonna space the seat forward a bit to get the clearance I need. I’ll post more once I do hopefully next few days

 

Also for better bass and clearance try pulling the plastic panel off of the seat back that the subs fire into.

We used to get a lot of "flutter" sounds as well from the vent flaps on the back wall from higher SPL sound systems. You can hear that one best if you stand outside the truck with the doors closed with the system playing. We would pull the vents, silicone ABS platic sheet cutout to the same footprint in their place, and sound deaden over the top of the whole thing.

 

Yea all the plastics are completely off, and actually I did want to know about that because those flaps are kind of annoying. Can I just remove the whole plastic piece with the flaps and cover it with sound deadening? I understand it’s for air flow but what would be affected if I cover that whole where the flaps are?

 

Yes, you remove the whole assembly. It is snapped into place with some barbs that are molded into the piece. Take that piece and trace it out onto a piece of plastic .We would normally use 1/8" ABS plastic. You can buy that in 12" square sheets from Ebay or Amazon. Then put a silicone bead around the face of the opening, press the ABS piece into place and cover it with a piece of sound dampening material that overlaps the whole thing. The only down side is that you will notice that it will take a little more force to close your doors because of the pressure not releasing from the cab. Also if you sit in the truck while someone slams the door, you will also feel that pressure more in your ears. It is not that bad though.

 

ohh ok, that doesn’t worry me too much really I don’t mind. If anything if I see it’ll be a problem what I can do is cover one of the openings completely and the other one I can leave the vent and put a mesh allowing the pressure to escape and leave the flap up against the mesh and it’ll resolve both problems

 

I would be careful about removing/covering those vents. My understanding is they are also used if your airbags go off to help prevent blowing out your ear drums. Get some Butyl rope and smash it in between the vent assembly and back wall. It will prevent the assembly from rattling. There are might be cheaper alternatives but here is one product that will work -

Damplifier Second Skin Butyl Sealant Tape – Butyl Rubber Sealant and Multi-Purpose Butyl Rope for All Vehicles (Car, RV, Marine) – 1/4” x 1/2" x 20’ – Made in The USA (3)

https://www.amazon.com/Damplifier-Second-Skin-Butyl-Sealant/dp/B016YQCWA4

 

You can certainly try that if you like, but my prediction is that you will get road noise through the mesh as well as hot or cold air from outside.

As far as putting butyl rubber back there, I would definitely not recommend that. That stuff melts all over the place when it gets hot. It also won't stop your flutter sounds unless you filled the whole vent flap with it. Your call on that.
Airbags always seem to jack people up when they go off, but I have never heard of someone's ear drums being blown out by something like that. I couldn't count how many customer vehicles that we did this procedure to, and never any issues. Again, your call.