Just looking for opinions, I've been reading for a while and was contemplating trying to upgrade the sub in the stock location, but I decided to reuse the stuff I took out of my Impala that is taking up space in the house, it's a little bigger than I'll need but I can always turn the gain down. I have an Alpine MRP-M850 mono amp (800 watts at 2 ohms, 500 at 4 ohms) and 2 MTX Thunder 5500 12's (4 ohms each) in separate sealed boxes. I have them separate cause I used to run 1 box on each side of the trunk and occasionally would take one out if I had extra junk, or both for the track. I figure I'll try it with just 1 box first, then 2, and determine if it's worth having the second one in and then figure out what to do about boxes as it'll look kinda stupid in there (which is my lowest priority because I'm not putting out any money, it was spent years ago). Also I'll be running a 4 gauge power wire as that's what I already have and a JL top post terminal that accepts ring terminals as well. The amp accepts speaker level inputs so I'm going to just cut the wire for the stock and go from there. Remote wire will be whatever junk wire I have lying around going to an add a fuse.

So that being said, I'm gonna remove the stock sub since it will be dead weight and sound deaden the rear deck. My deck already has the dealer felt fix installed (did nothing to reduce rattles). I also have a large roll of Fatmat lying around that was purchased forever ago. Being as I'll have 12's in sealed boxes and run between 5-800 watts, would I be better off filling the hole left from the stock 8" or leaving it open to let more sound into the cabin? In the Impala I had 2 smaller holes in the deck and it did make a difference in the cabin. I'm just trying to think which way I will have the least rattles, obviously it's going to overpower the stock amp (not changing it anytime soon) but with that setup and 4 6.5's running off of a low powered head unit in the other car it didn't completely drown it out so I'll be good for a while. Also if it makes a difference I have no plans to change the rear speakers since they'll be just for a little fill, I normally set the sound to go mostly to the front, so will it make any difference in the sound of those speakers if the rear deck is sealed up or not? Also I saw in the infinite baffle threads people were removing the cargo pass through, does that door rattle or make much difference? On my Impala there was also an armrest but it wasn't necessarily designed for a pass through but I did remove the sound deadening behind and it was much louder with the armrest down.

Sorry if I'm rambling, I'm not new to car audio but I'm new enough to this type of car. I'm just sick of the stock sub sucking and rattling the rear deck and have some good equipment that was taking up space, might as well put it to use.

Any input is appreciated.

 

I would leave the old sub out and let that air come into the cabin. With 2 12s you'll have lot of pressure in the trunk, plus you'll feel more in the car.

 

you will be fine leaving it open

 

Thanks that's what I'm thinking, with 2 12's the trunk will need to release some pressure. The car I took them out of, I used to love to sit stuff on the trunk lid and watch it dance lol.

 

you complained about the rear deck lid rattling from factory sub and now your putting (2) 12s in the trunk?? you are going to have a lot more stuff rattling besides the deck lid.

I have designed sub boxes for several customers and have tested all sorts of ported/vented boxes and there are ways to eliminate trunk rattle and direct it towards the front of the car.

 

That's why I'm gonna deaden the deck. I'm hoping the deck rattles less not having the sub directly in it.

 

you should leave the opening between the back seat and trunk open as well to vent in cab.

 

Yeah I'm thinking of taking that door out while I have the back seat out. I don't really see the point in having a locked door to the trunk, what are the odds you'd get hassled if you had an open bottle or some firearms and could access them from the cabin, a lot of cars flip down easy...

 

Another crazy idea I'm thinking of is to spray the underside of the rear deck/shelf trim with undercoating/sound deadener. I saw a pic of it somewhere on here and it looks like a bunch of white plastic support pieces. My rattle I have now sounds like plastic hitting on something. I figure it can't hurt, might just smell for a few days.

 

OMG! DON'T
think about it, it's extra weight, not smell or color that stops the vibrations

BTW the old sub is just that - extra weight!

i've heard of people welding disk weights to heavy up sheet metal

 

I removed the stock sub and put in a single 12 with 500 watts this weekend (my boxes were bigger than I thought/the TL trunk is smaller than I thought). Almost no rattles, way less than with the stock sub cause it's not vibrating directly on the deck. I have a 1.25 cubic foot box and the sub is facing the rear of the car, sounds good. If I can find somebody to buy the set of 12's I have though I might do a single 10" to save space as it doesn't take much to make this car thump lol.

 

I wouldn't give up the 12s even if you don't use all of their output. A 10" will require significantly more excursion for the same SPL which will increase distortion and raise power requirements. That's why I have a pair of 15s, maybe 1mm of excursion during normal listening, distortion is very low and 250w each will get stupid loud. Keep the 12s.

 

I probably will but I'm gonna need a new box. In the past I ran 2 10's and it never compared to having 2 12's but it was in a much larger vehicle. I have my gain almost off and the single 12 fills the TL effortlessly. I do prefer larger speakers but when set up right small stuff can bang well, my uncle has 4 6.5"s in an Avalanche under the rear seat so the mid gate still works and pounds really well since the cab is smaller than filling a whole car. I'm used to B body GM's where you typically need to go big, the TL is the smallest car I've ever owned which is why I think the 10 would be adequate.

I know Infinite Baffle yada yada... maybe someday.

 

I put the second 12" in this weekend and screw it I'm gonna run 2 12's it feels like it hits much lower in the cabin. Rattles in the car aren't bad at all, sounds awesome compared to stock sub (not that it's a fair comparison but compared to being in the rear deck). The trunk lid is another story but deadening that is a project for warmer weather. I still have my gain on the amp almost all the way down and the sub setting on the head unit one or two clicks from the bottom.

 

So you like the sub firing toward the front of the car? Maybe it's my setup, but mine sounds better facing the back. And, my exterior trunk rattles are pretty much the same. I have noticed that it is louder with the pass through open like others have said. I love how the sub looks firing toward the front though.

 

My subs are facing the rear, if I ever do an IB setup obviously it would be forward but I do agree facing the back sounds best. I tried listening in the back seat and it's uncomfortable sitting there lol. I couldn't imagine having them face the seat and being able to sit back there. It definitely is way louder in the back seat. I guess next time I need a back massage I'll sit in the back with ear plugs and the volume up.

 

+1

Yes facing rear is the loudest for sure. I have a 13.5 JL W6 with 1000+ watts and that thing hits hard. Custom spec box. Just make sure to fatmat the trunk lid, I took off my carpet and did the whole thing. It might also rattle where the trunk meets the body of the car when it closes. I added fatmat and NO rattle anymore just a LITTLE from my license plate, but when you play the music cant hear the rattle outside either. Fatmat 2 layers on my license plate also. Helped A LOT
I also left my stock sub there even when it wasnt playing. IDK why... Took that thing out and left the hole there. Also leave my back seat passthrough open. Doesnt sound as good to me when its closed and it will cause more rattle from the pressure.