Hi all. Has anyone else had issues with aftermarket subs and rear dash flexing? It's really flimsey steel and anything above stock volume levels (I have a dedicated sub amp) the rear dash violently vibrates. I'm not talking earth shattering volume levels... it doesn't take much to get it all moving.

I'm going to install some sound dampening material to help with the noise but I don't think I'll be able to get the power-robbing flex out of the flimsy metal on certain notes. What's your experience with aftermarket subs? Is it even worth it?

 

I put a 10" in my rear deck to replace the 8" Nakamichi sub that unfortunately died as well as a dedicated amplified. The rear deck does have a nasty vibration at medium to high volumes. I too thought of adding some sound deadening to the rear panel to fix it, but instead I'm going the route of putting the 10" into a dedicated vented box in the trunk. No modern subwoofer is designed to work in a free-air environment and I'm pretty positive this is going to make the 10" perform a lot better as well as stop any rattles. The trunk is huge, I don't think I'll struggle with the reduced trunk space.

 

I started with a sub and box in the trunk but the trunk is not very deep so hauling luggage on long trips meant no sub unless I can put something in the OEM spot.

I'm using the shallow pioneer 8" free air sub which fits OK with minor modification:

https://www.crutchfield.com/S-4Oae0p...SABEgL6H_D_BwE

It has the potential of sounding great if I can reduce the flex and noise.

 

I assume youve done everything you can to ensure the sub is well sealed and mounted to the rear deck surface? $30 of sound deadening to the underside of the rear deck definitely wouldnt hurt anything. Not sure what else could be done other than extensive mods to the rear shelf metal structure to reduce flex and vibration.

 

A post offering possible ways to alleviate mid range and bass issues.

https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/899537-speaker-frame-damping.html

Treated all of my door speaker frames ("spider")

Best way to contain, and, or, reduce NVH is closest to its source.

Used 4mm DEI BOOMMAT

Am interested in feedback pro and con.

 

I did some close listening and the primary offender is the middle seatbelt recoil mechanism. just to the right side of the subwoofer. Something inside of it rattles and is transmitted through the entire rear dash.

 

I have this exact problem - factory equipped subwoofer baked away in the desert sun so I replaced with a Pioneer (I think) free-air capable 8" unit. At some frequencies it sounds great, but at others it rattles the rear dash so loud that it can be heard from outside the car with all the doors closed.... terrible

I put a couple square feet of Dynomat on the rear deck and surrounding the sub itself but it didn't noticeably help.. I'll have to look in to the seat belt mechanism and see if that's it. If it is, I'll probably completely remove it; couldn't tell you the last time I had someone sitting in the middle back seat anyways.

 

Final update - I put a layer of dynomat across the entire rear dash and over/around the seatbelt tensioners. I made sure all the wires were covered with foam, ect. Sub mounted extremely tight with bolts/nuts. Once everything was back together the rattles are much reduced. At certain frequencies the 3rd brake light has a rattle which I can address later (bulb needs replacement anyways). It's "acceptable" now I think....only really noticable when sitting in the back seat and cranked up beyond reasonable levels IMO. time will tell.