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Discussion Starter #1
Here's what I have planned so far:
* Amp: Alpine MRX M50
* Sub: Boston Acoustics G312-44

My plan is to use the speaker-level inputs with the amp initially, using some of this multi-conductor wire. If I'm not happy with how that works then I'll upgrade to a DSP later. My concern with running from the speakers is that the factory head unit (which I'm very happy with) blocks lower frequencies from going to those speakers. I've noticed that some of the previous model year Focus harnesses had a sub output that could be tapped into, I'm really hoping that the 2012 has one too.

In my last 2 setups I had a 1 farad capacitor, so I think I'll add this Scosche one right from the start. I do have a question about wiring though:
* Since the amp is only 500W rms, is a big 3 upgrade even necessary?

I'm thinking of wiring the sub for 2ohms and putting it in a 1.0 ft^3 sealed box made out of 3/4" MDF. I have some questions about this:
* since the box is that small, how much bracing is needed?
* is it alright if I go a little over on the volume? (e.g. 1.04 ft ^3)
* should I use that polyfil stuff even if the volume is the correct size?

I'm not sure how loud a single 375W rms 12 in a sealed box will be, so I'm thinking that if it isn't loud enough, I'll buy a second amp and 12 later. OR instead of the BA 12s, I could just go with a JL 13W6V2 in a vented enclosure right off the bat, but that would be considerably more money, and a lot more work would have to go into building the box too.
 

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Vince your Moderator
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Go with a bigger amp and get the JL sub w/ a JL box that is made for it and call it a day.
 

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Discussion Starter #3
Go with a bigger amp and get the JL sub w/ a JL box that is made for it and call it a day.
I don't know if I'd really need a bigger amp. It's over twice the rms of the ones in my previous 2 cars, which I was content with. I never looked into the pre-built JL boxes though, I'll check 'em out, thanks.
 

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you need bigger wire then that i wouldnt even use that for door speakers. 300 watts you need atleast 8 gauge not that 18 gauge.
 

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Discussion Starter #5
you need bigger wire then that i wouldnt even use that for door speakers. 300 watts you need atleast 8 gauge not that 18 gauge.
Haha! I meant I was using that just for the speaker-level input, sorry if that wasn't clear. I have some 8 gauge for the speaker itself.

I think 18 would be a fire hazard at that level!
 

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Discussion Starter #6
Go with a bigger amp and get the JL sub w/ a JL box that is made for it and call it a day.
Man, these W7 ProWedge boxes look pretty solid. I wonder if a single 10" with a 600W RMS @3ohm would be enough, although a bit more than I was planning on spending. I'll have to look into a JL dealer to see if I could hear it in person...

Otherwise I think the 12" with a 800W RMS amp would definitely be enough. ~$1350 total would be more than I could afford right now though. Don't get me wrong, I don't mind paying for quality, but I also don't want to pay for more than I need - just looking to supplement, not enter contests.
 

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Vince your Moderator
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Nice ride man. I only run 450ish to my sub and I am pretty happy with it. The reason I recommended a bigger amp for the JL is because you can be way into distortion before you can hear it in a sub, which is clipping. Clipping is a square wave which kills speakers. But looking at JL's site, 500-700 RMS should be near perfect.

This all being said, what kind of wood working skills do you have?
 

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Discussion Starter #8 (Edited)
Nice ride man. I only run 450ish to my sub and I am pretty happy with it. The reason I recommended a bigger amp for the JL is because you can be way into distortion before you can hear it in a sub, which is clipping. Clipping is a square wave which kills speakers. But looking at JL's site, 500-700 RMS should be near perfect.

This all being said, what kind of wood working skills do you have?
Thanks! I was actually admiring your trunk setup last night.

I agree about the clipping too. The thing with the W7's is that they're 3ohm, so I don't think that original Alpine amp I was looking at would be enough. I'll have to take a look at their other boxes to see is there's anything more economical that runs at 2ohm.

For wood working skills, I could handle building basic shapes like wedges or cubes, but not much beyond that. I've built the last 3 sub boxes I've had with few problems. (A big ported for a MTX 15 and 2 smaller sealed boxes for a pair of Pioneer 10s)

Edit: I had a chance to check out some of JL's other enclosures, the CVS112RG-W6v2 seems to be a great fit for me, the 12W6v2-D4 it uses has decent specs and would work well with the original Alpine amp I liked. I don't really like its vinyl coating, but it looks nicer than anything I'd put together myself and it's just going to sit in my trunk where no one ever sees it anyways. As an added bonus the enclosure is on sale at a couple authorized JL dealers online for just $50 more than the speaker itself. Now to double-check my trunk measurements...
 

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Vince your Moderator
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The dub6 is a good driver for sure.
 

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that apline might not even want to work with that jl. some amps will go into protect if its reading a weird ohm to it
 

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Discussion Starter #11
that apline might not even want to work with that jl. some amps will go into protect if its reading a weird ohm to it
It is kinda weird that JL went with 3ohms. Maybe they expect people to buy them in 6-packs?
 

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jl likes to try to make it so that your only real option for an amp is a jl amp.
 

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Vince your Moderator
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^true. A JBL P1224 WOULD BE AWESOME!
 

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Discussion Starter #18
dont know the brand but looks like junk to me. be better of with 2 10 or 12 that can handle 1000+ rms. takes up less space and just as loud. not to mention a 21" sub wont be able to reproduce the sound aswell. as for the air space needed i would gues about 5cu feet aka the whole trunk. the amp would have to go on the back seat.
Yeah, that's what I was thinking. The lack of small params doesn't bode well for it.

Whatever I end up getting/building, I'm not going to go with anything larger that 2 cu ft.
 

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Death Penalty makes really good equipment....but for the size box your speaking of and everything I would look up sundown SA-8's alot of people use them and Like them Ive heard a few and by far the best 8s I have ever heard
 

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Discussion Starter #20 (Edited)
Death Penalty makes really good equipment....but for the size box your speaking of and everything I would look up sundown SA-8's alot of people use them and Like them Ive heard a few and by far the best 8s I have ever heard
I've heard good things about Sundown's stuff, but I've never heard them in person. Even their 10s and 12s don't need much space. I think I'm going to need to make a spreadsheet to compare all of these...
 
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