Right now I'm running a Pioneer DEH-8MP head unit with some cheap but decent Pioneer 4x6's in the front and 6.5's in the sail panel (which never had holes for 6x9's, oddly enough, but the car's build sheet doesn't indicate a radio-delete or anything like that... whatever).

First question:

I just ordered two MB Quart 12" DWF-304 subs (dual voice coils, 200watts RMS per coil @ 4ohm) and an Elemental Designs NINe.2 amp. The amp is rated at 400x1 @ 4ohm when bridged. As I understand it, my best wiring option would be to wire the two coils on each sub in series (bringing impedance to 8ohm per sub) and then wire the two subs in parallel to the bridged amp, bringing impedance back to 4ohm. Is this correct?

Second question:

What type of wiring do you suggest I run? I can say for certain that I do not plan to move to a significantly more powerful system in the future, though there is a chance that I might add a modest 4-channel amp at some point. I was planning to upgrade my Big 3 to 1/0awg, and to run 4awg to the hatch area, then use a distro block and run 8awg to the amp. Should this be sufficient, or will I be better off running 2 or even 1 before the block?

Third question:

I also ordered some Infinity Kappa 462.7cfp 4x6 plates to go up front and plan to run them off the head unit. The manual for the Kappas (which I found online, the speakers haven't arrived yet) says that they have an inline crossover and not to use another one; the listed frequency response range is 75hz-25khz, so I assume the crossover is a 75hz high pass. Would I gain anything from turning on my head unit's built-in HPF at 125hz, or would the effect be negligible?

Fourth question:

The head unit also has a built-in low-pass filter for the subwoofer output, but only offers 50/80/125hz as the settings. This filter can be bypassed. The amp has a variable low-pass crossover that ranges from 40-240hz. The subs list as their range 18-300hz; should I just use the amp's crossover at 240hz, or should I find an inline crossover at 300hz? Or for that matter, would I be better off using just the amp's crossover at around 200hz and letting the rear 6.5's and the Kappas blend in with it? Or is there something else entirely that would be even better?


Thanks for any help; I'm still fairly new to car audio. I can pick and install a head unit and regular speakers, but anything more complicated than that (e.g. subs/amps/crossovers) is new territory for me.

-------
Links to the new components, if anyone wants them:
Subs: http://www.crutchfield.com/S-nQ1OZtV...20&I=049DWF304
Amp: http://edesignaudio.com/product.php?...pid=24&cur=USD
Infinity Kappas: http://www.crutchfield.com/S-nQ1OZtV...0&I=1084627CFP

 

First question:

No, you want to wire the amp down as low as possible. Run the coils in parallel giving you 2 ohms per sub and then run the subs in parallel giving you a 1 ohm load for the amp (run the subs in mono). This will feed the two subs 400 watts rms @ 12.5 volts (what ED rates their amps at, expect more at 14.4).

Second question:

See my post in this thread. Also, consider welder's wire. It's significantly cheaper than 'car audio' wire, functions exactly the same, and might even be more durable. The downside is that the largest welder’s wire I have been able to find is 2 gauge. Instead of rewriting what I wrote previously, just read my post and mean's posts in the thread I linked to

Third question:

I'm not sure why you would want to run two crossovers. If anything don't use the one that's coming with the speakers and only use the one on your HU. Most people use their HU to cross their speakers but some people run the in line crossovers (also sold as bass blockers) because their head doesn’t have built in crossovers. Running two crossovers will be weird in that you will have a slope at 125 Hz and then a steeper slop at 75 Hz. It might not be very audible but it’s still a little weird.

Fourth question:

From what I understand you're trying to figure out where to cross your subs. As a rule of thumb you usually want to stay around 80 Hz or lower. Anything above that and sound starts to become directional – that is you can tell the lower frequencies are coming from the back. That said, I’m not sure how much you want to limit yourself to that because you’re going to be running rear speakers. Play around and do whatever sounds best. Also keep in mind that most subs can’t play higher frequency sounds very accurately.

Post up if you disagree or have any questions.

 

So... run big cable just because that's what you do when you run cable (uh, the generic you, not you in particular), cross the speakers only once with either method, cross the subs low, and show the amp a 1ohm load. Works for me, except that I haven't found anything to tell me if the amp is stable to 1ohm. Perhaps you (or anyone else here?) know that from experience?

Thanks for the input!

 

Run big cable because it sucks to have to run cable a second time because you didn't run a big enough wire the first time saves you money in the long run.

As for 1 ohm, ED lists it on their site http://edesignaudio.com/product.php?...=Specs&cur=USD

 

I may just be blind, but all I see in the specs page is:


400x1 @ 4 ohm
150x2 @ 2 ohm
100x2 @ 4 ohm

 

Good call. Do what you were orginally planning on doing wiring wise and you should be fine

 

1. Yes

2. Your plan sounds fine: 4 gauge to a distro block, and 8 gauge to the amp. If all you're running right now is that amp, forget about the distro block and run the 4 gauge right to the amp. Buy the distro block and the 8 gauge later on when you add the other amp.

3. I would guess that the crossover that your manual mentions is the one between the woofer and tweeter. You absolutely want to high-pass those 4x6s or you'll kill them. The 125hz high pass from your head unit will be sufficient.

4. You can use either the head unit's low pass filter or the amp's. The amp's will give you more flexibility, but it probably isn't necessary. You do not want to run your subs up to 200 or 240hz because you'll have too much high frequency junk coming from the subs. Like Gummie said, somewhere around 80hz usually seems to work best in a modest install like this. I've found that above 90-100hz, there's way too much upper frequency stuff coming through and it really ruins the sound. Too far below 80hz and you wind up with too much of a gap between the sub and the other speakers. 80hz seems to be about the best comprimise.