First install, first flop.

[g.ruff561]

I have a 92 E30 M-Technic convertible. Currently I am running an Alpine head with Alpine type-r 5.25 front fill and custom cut rear fill co-ax. Both fills are the same model. My first problem is, when I turn up the volume, the sound is distorted at high volume. As far as i know, I am running this system off of the head unit power. As a side issue to that, it seems that the volume in the rear is louder. I have to tweek the fader to get equal volume. I do realize that the front speakers are in the kick panels. However there is a distinct differance in volume. My next question is, I want to mount one 10" sub thru the rear seat back. I will remove the rear leather seat back, carpet the exposed metal and build the sub inclosure from the trunk back. I have one Alpine 4 channel amp for mid/high and one Alpine mono to mate with the 10" sub. The rear seat bottom will remain in place. It it rarely used anyway. Any suggestions would be a blessing. P.S. any suggestions on the sub make/model.

[Scotty89]

If you've got Alpine everything else, why not go an Alpine sub as well.

Alpine make very decent subwoofers - they might not be the greatest in the world, but for their price and availability, they will definately compete with anything in the same sort of range.

A Type-R 10" would probably suit you They run 500wrms a piece, so you want a monoblock of atleast 500wrms to get the most out of it.

[g.ruff561]

Any advice on the sub configuration??? And what would be your take on the sub build-out????

[Scotty89]

Sub configuration? 1 sub woofer directly connected to your mono block?

Sub build-out? Like enclosure type or something?

If you are building the box to fit a specified area it would be easier to build a sealed box. Then you will not have to deal with calculating the port width/length/depth etc.

A ported box will sound louder, but the bass will not be as tight. If you want a ported box, it would be easier to buy a pre built one.

[g.ruff561]

As stated I am considering finding a way to mount the sub by making a cut-out in the metal rear seat back, and mounting the sub in a sealed box so that it fires into the passenger compartmant. I prefer a tight bass. A solid thud not a lingering boom. Then carpet the remainder of the rear sheet metal with carpet. I dont know why but it seems to me that as much money as a good sub costs, you are losing a lot of your bass by having the sub fire backwards and out of the trunk. A lot of rattle for nothing. With or without dyna-mat. The rear passenger seat bottom will still be used. My bordeaux rides the back seat, top down and sunglasses. she is a roit. I like your idea of staying with the Alpine name brand. However, I am looking at one jl audio 10w7, or two jl 8". Thanks for the feed back.

[Scotty89]

I am not too sure, but I definitely wouldn't go cutting up your seats.

I can see that you don't want to seal it off in the boot compartment (I ride with the rear seats folded flat, so the cabin + boot are not sealed from one another), as it definitely does suppress the kick quite a lot.

I also wouldn't go building the box onto the rear of the seat (unless they are fixed in a 'vert? I wouldn't know...)
You should build a sealed box, and put it in the boot, and work about a port/vent into the passenger compartment, hopefully something not so permanent/irreversible.

Also, firing the sub backwards - it definitely a good idea, even just to try it out and hear for yourself.

I honestly thought it was stupid too, until i tried it. When the sub + port fire backwards, there is much more bass loading gained because the sound bounces off the inside of the boot. You will gain more rattle, but also more bass - then if you dynamat, you can eliminate most of the rattling and gain more bass. Definitely worth the extra effort though.

Also checked out the JL audio 10w7 - optimum RMS power is between 250 - 500wrms, and the reviews seem to be that its a great driver - though its fairly pricey for its size and power I'd think. It sure does look like one tough mofo though, I sure hope it doesn't disembowel any passengers riding in your rear seats.

EDIT: Looking at the specs of the 10w7, it says nominal impedance is 3 ohms, and DC resistance is 2.75 ohms. From that I am gathering that its 3 ohms... I'm not familiar with any 3 ohm setups, not sure how it will wire up to the alpine amp. I guess you will have to aim for a 2 ohm setup on the amp if you can - From my understanding, you might cause damage to the amp if it runs without enough resistance in the circuit (e.g, a 4 ohm amp setup rating, with only 3 ohms resistance from the sub).

[Scotty89]

Which alpine amplifier is it you are using for the sub? You may be able to find a more suitable subwoofer to pair with it.

[bmw528i]

Originally Posted by Scotty89

I am not too sure, but I definitely wouldn't go cutting up your seats.

I can see that you don't want to seal it off in the boot compartment (I ride with the rear seats folded flat, so the cabin + boot are not sealed from one another), as it definitely does suppress the kick quite a lot.

I also wouldn't go building the box onto the rear of the seat (unless they are fixed in a 'vert? I wouldn't know...)
You should build a sealed box, and put it in the boot, and work about a port/vent into the passenger compartment, hopefully something not so permanent/irreversible.

Also, firing the sub backwards - it definitely a good idea, even just to try it out and hear for yourself.

If you have an amplifier that is 2ohm stable, I can't imagine it would be much of a problem. However, if you want a 10w7 I think you should strongly consider a JL Audio 500/1 as they are stable and consistent from 1.5ohms to 4 ohms.
I honestly thought it was stupid too, until i tried it. When the sub + port fire backwards, there is much more bass loading gained because the sound bounces off the inside of the boot. You will gain more rattle, but also more bass - then if you dynamat, you can eliminate most of the rattling and gain more bass. Definitely worth the extra effort though.

Also checked out the JL audio 10w7 - optimum RMS power is between 250 - 500wrms, and the reviews seem to be that its a great driver - though its fairly pricey for its size and power I'd think. It sure does look like one tough mofo though, I sure hope it doesn't disembowel any passengers riding in your rear seats.

EDIT: Looking at the specs of the 10w7, it says nominal impedance is 3 ohms, and DC resistance is 2.75 ohms. From that I am gathering that its 3 ohms... I'm not familiar with any 3 ohm setups, not sure how it will wire up to the alpine amp. I guess you will have to aim for a 2 ohm setup on the amp if you can - From my understanding, you might cause damage to the amp if it runs without enough resistance in the circuit (e.g, a 4 ohm amp setup rating, with only 3 ohms resistance from the sub).

[g.ruff561]

Thanks for the feed back. I am not cutting the leather seat. I will be cutting a square section the size of my sub box out of the medal panel that seperates the rear seats and the trunk. The box is already made and 1 10' sub is all I would need. By the way, the box is non-ported and I now have to figure a way to mount the box mid way up the sheet medal back and low enough not to interfere with the power top operation. Fixing the sub box flush with the sheet medal and stablizing it enough so it does not shift around is still going to be a major challenge. The back top section of my rear seats will not be used. A good quality carpet will be used to give a custom look to the rear seat back and trim around the sub box cut out. Hit me back with any ideas. Thanks, G.

[MachineHD]

check out this thread for custom e30 subwoofer enclosures

The New Subwoofer box FS thread - Page 13 - R3VLimited Forums

cheers!

[g.ruff561]

My problem is that I do not have a center armrest in my 92 E30 Mtechnic.