sld

I have a '00 GS300

It was suggested that mounting the sub in a sealed box, and hanging it under the rear deck, allowing it to fire directly into the cabin is the best way install my JL 12W7. Winner or loser?

The car has sealed cabin(steel plate behind back seats) with stock 10" currently mounted in rear deck.

What cha think?

Stealther

Thats not a light object that you would be hanging up there. I'm sure you could get away with it, but I wouldnt! I'd be concerned about it when I went over RR tracks at 70

Of course I'm not the most daring person when it comes to installs

sld

It would be in a sealed box that would run to the floor and be braced on the sides, so it wouldn't be stressing the rear deck at all.

Its more of a question of SQ.

fast400

I tried a 10W7 and ended with a ID12 in free air. The box for the 12W7 will be large and take up some space.

retrodrive

That would work but I am pretty sure you will notice a little difference in handling. Make sure you brace it to the trunk floor real well.

LexLS

Although I'm not totally familiar with the GS, if it's anything near the LS it should work. I put my 10" sub in a sealed box and bolted it to the rear deck, it's very solid. Even though it was solid, I did use a new wall for additional support, the box probably weighs 30+ pounds.
Box Mounted
Wall supporting box
Just some ideas for ya. If you can fire it directly into the cabin that would probably be best. That just wasn't feasible for me due to the gas tank.

Earl!

engin_ear

iTrader: (1)

I have a 60 pound box hanging from my rear deck (GS), but not without major anxiety, pain, and carefullness, and anxiety. Sorry, did I mention anxiety? It has been stable for a year now. I only have a small spacer under it to prevent up and down vibrations from becoming too resonant and shaking the whole thing apart.
So it can be done, but I really don't recommend it. The rear deck sheetmetal is garbage. It is a thin gauge metal, and will bend EASILY with any kind of torque applied to it. One trick is to make sure that the load is as distributed as possible, by using multiple brackets anywhere you can fit. Another option is to brace the deck as well, with some 1 foot long or so angle brackets from Home Depot. I also used very large washers above and below the deck on the mounting bolts, to prevent them from pulling through the sheetmetal over time.

An alternate way is to rest the box on the trunk floor and make a spacer (or 'chimney') of some sort to duct the woofer to the stock woofer hole, so that no air escapes into the trunk compartment.

That said, the reason I did it that way was for SQ, and I haven't regretted it a bit for that reason. If you're only using one woofer, I believe that the best SQ is obtained by directing it straight into the cabin (as the stock woofer is). This minimizes resonances from the other parts of the rear of the car, like the rear fender wells, trunk lid, etc. It does not totally eliminate it, though. (My spoiler still vibrates.)

Car handling not really affected. I think it is because the box sits between the rear wheels, and not more rearward.

engin_ear

iTrader: (1)

Also watch out for the W7's max excursion. You may have to enlarge the stock woofer hole, or build the box so that the woofer sits well below the deck. Otherwise, she bangs.

TTurboPimp

iTrader: (12)

I would not recommend it. The 12W7 uses a small enclosure, so it can be done, but I dont think you will be happy with the outcome. I have a 12W6V2 in my GS, and I contimplated doing the same thing. I talked to alot of high end installers in my area, the common response was it doesnt sound good firing up through the hole. For starters you will need to open up the hole a little, which isnt that big of a deal. Then you need to worry about the excursion of the sub, which will be a descent amount. The problem with the excursion issue is that you really want the sub box flushed against the deck to avoid cancellation that will be caused by the 1 to 2 inches of space that you will end up with between the box and the deck. The shop that I use has tried it with both a GS and a Caddy, the results sucked on both of them. I ended up with mine firing towards the back of the trunk, and it sounds great. Someone else on CL has subs mounted flush against the rear seat, the space behind the fold down armrest is cut out, and the subs are firing into the seat itslef. Thats an idea also.

Good Luck!

engin_ear

iTrader: (1)

* The problem with the excursion issue is that you really want the sub box flushed against the deck to avoid cancellation that will be caused by the 1 to 2 inches of space that you will end up with between the box and the deck. *

This problem is solved by making spacer(s) out of either wood (MDF) or styrofoam to fill this gap. But yeah, I agree with your points, TTP.

sld

The installer I talked with said it would sit in the deck and look just like the factory 10, but would be in a sealed box under the deck. Mounted this way there would be no excursion or cancellation issues. Yes the hole would need to be bigger, although I'm not sure if they would make a custom deck. I saw an Audi they did with 2 10W7s in the rear deck with a sealed box under it and it looked very good, but I didn't hear it b/c it wasn't done yet. According to this guy, its the only way to get good bass in the cabin, b/c the cabin is sealed by the plate behind the seats.

I'm afraid if I just put the sub in a box and fire it towards the rear using the open hole from the stock 10, I won't get good bass in the cabin. Also, I'm worried I'm gonna get a lot of rattles with a rear-firing set up.

sld

TTurboPimp, I love how your install looks. Is your box sealed or ported up through the factory sub hole? Do you get a lot of good clean bass in the cabin? Trunk rattles?

engin_ear

iTrader: (1)

*** According to this guy, its the only way to get good bass in the cabin, b/c the cabin is sealed by the plate behind the seats.

Sld:
In a GS, there is no plate behind the seats, like there may be in other cars. There are only three reinforcing metal braces (which you may see in some pre-install pics). They are covered by the material that covers the inside trunk area. So you can get significant bass from the trunk into the cabin.

sld

Dumb question, but does the leather seats inhibit the bass?

TTurboPimp

iTrader: (12)

sld, My box is sealed, which I think is the only way to go with the JL subs(just my opinion, others may disagree with this). The sub fires towards the rear of the car with no real off the wall rattling, some, but not a rediculous amount that I have heard in other cars. We took out the factory sub, which also allows the sound to get through some more, there is about 2" of space between the top of my box/ amp rack and the rear deck.

Trust me, you can get more bass than you will ever need into the cabin without firing the sub through the factory hole.