Help me design a trunk setup

[Digitalwave]

Let me give you the run down of my current setup before I post my intention:

Head unit: Eclipse 5504 non-powered deck with 3 sets of 8v preouts (subs are non-fading).

Power: Hifonics Zeus 110x4 @ 2ohms with built in crossovers mounted in the trunk.

Front speakers: Infinity Kappa 5 1/4" Components installed in stock locations with Dynamat.

Rear speakers: Infinity Kappa 5x7" two-ways custom mounted under stock speaker grills (premium).

Besides that the car is rewired with 16ga double shielded Monster cable and I have 8ga ground and power with no capacitor. I'm also running a set of 4 channel DEI RCA's that Ken recommended.

Now that that's out of the way, this is what I want to do. I am doing some things to make my car more streetable, such as fixing my A/C and going back to sport seats. I am quite happy with my audio setup right now, but the bass is lacking of course and the oval speakers distort before the fronts. I figured I can resell the rear speakers to recoup some of the cost of buying a single 10 or 12" sub.

My plan is to put the sub in a small box and build a false wall to mount the amp in, very similar to what Jordan's trunk setup is. I am going to be using the rear channels of my amp to power the sub. What is the best option for powering the sub with my rear 2 channels? Bridge them and run a single voice coil 2ohm sub? That will give me 220 watts RMS. What about DVC subs?

The type of music I listen to most is hardcore/metalcore, which super fast double bass and very technical bass riffs. I need a sub that can keep pace. I am not interested in boom boom since I don't listen to slow jams or anything, but I'd definately like to add depth to my music. I figure a 10" is best for this, and I know that 4ohm has better SQ than 2ohm but I don't think I'd get enough power out of my amp at 4ohm.

Should I stick with a small sealed box? There is a lot of talk about porting around here. I just think building a properly ported box is much harder than a small sealed one and I don't want to mess it up, because I know how vital box design is.

I am trying to keep the price of the sub in the $150 range. I should be able to sell my rear strut bar and my rear speakers for that much. Basically I am asking for box and sub suggestions, as in specific brands and models to look for, as well as the best way to setup my amp.

Thanks for any of you that read all this, I appreciate any suggestions.

[KenC]

You'll have to remember that if you bridge channels 3 and 4 to a single two-ohm sub, you'll be running a 1 ohm load on the amp. I'm not positive, but I'm fairly certain that the amp can't handle an impedence load that low (most 4 channels aren't meant to).

www.Carmedia1.com has really good pricing on Image Dynamics subwoofers. Definitely get a 10 if you want the fast punchy bass. I think the IDQ 10 with dual 2-ohm voice coils would work well. You would have to run the VCs in series to produce a 4 ohm load for the sub if you're going to bridge the rear channels of your amp to it. You'll also want to pick up a 1/2 farad cap.

[Digitalwave]

Does bridging automatically half the ohms? Like, if I bridged to a 4ohm sub it'd put a 2ohm load on the amp? That means the amp would put out 220 watts to that channel right? What if I had a DVC sub with 2ohm coils and ran each coil on their own channel, would that work and give each coil 110 watts?

My amp is 1 ohm stable. But I don't want to run into clipping problems.

EDIT: actually I don't think its 1 ohm stable.

[KenC]

You can't run a single channel to each voice coil. You need to run the coils in parallel or series. And yes, when you bridge an amp it will "half" the impedence load. If it really is one-ohm stable, you should be fine bridging it to a two ohm sub. However, you'll most likely need to upgrade to 4-gauge power and ground cables and definitely have to get a cap. You'll probably also want a fan to blow accross the heatsinks because it will generate a lot of heat at that low of an impedence level.

[Digitalwave]

From what I can tell its not 1 ohm stable. I am getting confused now though. The specs for the amp are 4 x 55 at 4 ohm, 4 x 110 at 2 ohm, or 2 x 220 at 4 ohms bridge. Does that mean if I run a 4 ohm sub bridged on the rear channels, I get a 4 ohm load and 220 watts to the sub?

I don't want to risk overheating the amp, clipping, or premature amp failure so I want to stick to a 4 ohm load.

[StereoInstaller1]

You must not be all that confused because you have it exactly correct.
Luke

[KenC]

Yes, if you bridge the rears to a 4 ohm sub, you will get 220 watts to it. Which should definitely be sufficient.

Check out the Image Dynamics IDQ10D2. It has dual 2 ohm voice coils, so you can run them in series to produce a 4 ohm load. It's only like $120 at carmedia.

[Digitalwave]

Awesome. I was looking at the Image Dynamics before. Must be a good sub for the money if you recommend it Ken. Luke, do you have any other sub suggestions as a counterpoint?

Ken, I really appreciate your help - I knew you'd be out there to help me out on this. Do you recommend I run a small sealed box for the IDQ10D2?

[KenC]

You would probably want to contact Image Dynamics regarding the box (volume, type, etc.). Or it should just be in the literature the sub comes with.

I know Luke runs a Kappa Perfect 12 in his car. He would probably have some good suggestions too as he's been in the business since the early 80s.

[Digitalwave]

What do you run in your car, Ken?

[PeaveyBassist]

IDQ 10 is good for the money. I've always heard good things about it. 0.5 cubes sealed should be good if you want a small box. I would get something a little larger like 0.75 cubes. If you are bridging the rear channels on the amp, either get a dual 2 ohm sub, or a single 4 ohm. Technically, when you bridge the 2 channels for a 4 ohm load... youre running each of those channels at 2 ohms.

Will

[Digitalwave]

Pending other suggestions, I think I am going to get the dual 2ohm IDQ10. Is the dual 2ohm arguably better than a single 4ohm though? I've never used a DVC sub, and besides the horribly obvious, I am unaware of the differences.

Size is not the factor that will determine my box sizing, I don't care how big it is but I want the tightest and best overall response I can get, which is going to determine how big the box is.

[PeaveyBassist]

Yea, I understand box sizes ;) I was a big audio guy for a couple years. I built a lot of boxes for people and shipped them all over the country. In a sealed box that small, the difference between 0.5 and 0.75 will be small. It will be different, but not like, "omg the .75 one sounds like poo and the .5 one sounds the bestest ever". Go to www.carstereos.org and ask them what they think. I was on there for a long time, left, and came back (long story). They are good guys with a LOT of good info.

Will

[Digitalwave]

Will, I didn't mean to insult your intelligence and I appreciate your help. I just didn't want a misunderstanding that I want to keep the box physically small for space reasons. The space isn't a big concern to me.

[PeaveyBassist]

I know TJ :) No hard feelings. Just lettin ya know about my background in car audio a little bit. The only thing I would be worried about with going with a really small box, is missing the low end extension that the sub is capable of.

Will