I've been searching, hoping that someone may have posted trunk measurements already, but no luck so far. Anyways, I have no speakers in the rear deck and do plan on losing the trunk spring bars. I have two 15s and will likely have to angle the speakers at a 45 degree upwards angle. I don't mind measuring myself, but if someone would care to share theirs, it would save me a bit of trouble and whomever plans this in the future.
The measurements that I took, and these are all maximum OD measurements, are for an angled box, for dual 10's. This box will sit under the rear package tray, inside the cubby in the back of the trunk. It would be fat at the bottom, and skinnier at the top, with the woofers angled somewhat upwards towards the trunk lid... Here's what I got:
Bottom depth (from taillights to back seat) : 12"
Top depth (same direction) : 6"
Length (parallel with backseat;inbetween shock towers) : 30"
Height: 11.75" MAX
those dimensions would rather comfotably hold two 10"s but you could I think, cram 3 10's into it if you wanted, or maybe even two 12"s if your real crafty. The biggest drawback is having absolutely no more than 11-3/4" from the floor to the top, I can't remember exactly what was in the way, I think it was the torsion bars though, but it could have been the rear deck speakers. you might have more room since your taking that stuff out, but I highly suggest you take a measurement if you go bigger than that. Also, IIRC the reason I angled the front face was because there was no way to make a rectangle box that could fit 12" depth all the way up because of some kind of clearance issue....
I still don't think that even with the angle and with the speakers and torsion bars removed, it would still be really tough to fit 15"s in the cubby. With those there's still the issue of only having 30" across, although I think that number could be stretched about an inch or so.
Your best bet for 15"s would just be to bite the bullet and put them in the main area of the trunk. But on that same note, two 15"s is major overkill for that car. I only have a single 12" in mine, being pushed by 300 watts and that sob is freakin loud and deep. I cant even turn my bass up all the way because it drowns out my music. And hah what's funny is that just the other day I rattled my gd cougar head off the side of my car somewhere down the road when I had my bass up lol. If you could come up with another use for your other woofer, just the one speaker should be more than plenty, and you would still have a little bit of trunk space left;)
its too bad your 5 hours away I could let you check out what I got going on with mine. There's a chance I might have to be going up to Live Oak later this year so maybe we could meet up there sometime.
Do the old fiberglass box setup. Get some wood hoops sized for your speakers, build a wodden box out of the shape you want your speaker to fit in with wooden dowls. Then stretch thin fabric over it and "paint" over it with fiberglass resin. Quick and easy fiberglass box custom fitted to your trunk. After you get a couple dried layers on there, pull it out and finish it outside the car.
I've honestly never done it, but was a trick "newbies" used a lot on the carputer forum I used to spend a lot of time on back in the day.
Depending on which brand and model of 15's you have will determine which approach you take. It typically takes less air space with a sealed enclosure than a ported enclosure. I would look to sell the 15's and buy a set of 12's. The will install almost at the same angle as the back of the rear seat or at least they will in an 83 car. I had 15's, 12', & 10's and the 12's were by far the better of the three as far as being able to play rap, rock, country, and grunge.
Darren
About ten years ago I built an enclosure with the drivers firing up under rear deck. It just so happened to be a pair of 15s. With this alignment, I had a major cancellation issue. It was so bad, I had no bass response aside from directly in front of the drivers themselves. Reflection is a bitch in this alignment. I suggest rethinking your plans.
I did the same thing with the 15's firing straight up into the rear package tray and the results were dismal so say the least. It was a pair of Kicker Comp 15's with an Orion amp in mono at about 600 watts so everything was there for some pretty good low end but the cancellation of the base wave from the reflection killed them. This same configuration in my buddy's 91 Fox Mustang hatch car was the complete opposite as it reflected off the angled glass of the hatch and made some powerful bass. Smaller does not always mean less but I will say buy as much amplifier as you can because under powering a sub will cause more distortion than over powering one and a person can always turn the gains down.
Darren
You can not "underpower" a driver and distortion has no effect on them either. They fail from thermal or mechanical failure. Thermal would be too much power, mechanical could be too much power, wrong enclosure, unloading under tuning, etc. . . A clipped signal can do damage as well, but that will induce extra heat which will lead to thermal failure. There are a lot of myths and marketing BS in the 12V automotive electronics world. If you want some good cheap education, join an audio forum or pick up and read a copy of the Loudspeaker Design Cookbook by Vance Dickason.
I was waiting for someone to say that. Thermal or mechanical failure can happen from over powering or under powering a sub. Granted 1000 watts on a 500 watt peak sub run wide open all the time will kill a sub just as well. I would see guys coming in the shop with a a pair of blown 12's and a cheesy amp that would barely support the bottom side of the 12's with the gain all the way up. The problem is they would listen to them at such a high volume that there was not enough power to pull the sub back before it was time to go back forward. This would cause distortion which basically sounds like shiznit and can cause mechanical damage. Granted a person could put a small amp on some subs and set up the system and advise the owner not to go past a certain volume level and they may listen to the advise and never have a problem. Not typical but I am sure there are a few people with that kind of restraint. IF you put an amp on the subs that has more power than necessary you can turn the gain down and actually have enough power to get the sub to respond the way is should. Clean and ample power, the correct box, and a good sub will make the most bass and sound the best in my opinion. There are all kinds of ways to build car audio systems and to each is their own.
You have been fed bad information my friend. Like I said, give that book a read or head over to a good audio forums and you'll quickly learn what is so wrong with what you typed.
I used two 12's in a box I built myself running 400W @ 4 Ohms and they worked great. If you want to adjust your configuration for two 12's, I would be happy to measure the box. I built it from 3/4 MDF to fit just under(I.E. Rubbing) the trunk lid springs..
Again, reading a book and reading what others post on an audio forum are good advise. I installed and sold car audio for years, won contests with my car and customers. I am just sharing what worked in the real world with how I installed it. There is more than one way to do it.
Sounds like the previous post will solve the OP's original question.
Darren
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Ive always been a real big fan of 10's just seem to hit just right for what I listen to. I made this box forever ago. Actually the box was built before I had my license.. and im 21 now so 6-7 years ago. I made it to fit on the package shelf and notched it for the 6x9's it fits perfectly with no clearence issues and I had a 1200 watt magnavox amp and 1.5 farad capacitor on the back of it. Totally sealed actually it hit so hard it was backing the wood screws out... 3/4 inch MDF