Ok, so I'm about to set up my sound system in my car but I have a couple last things to do. First, I need to make a box for my sub. does anyone have dimensions for a single 12" ported box that will fit in the well in the back? If i can't find any dimensions then ill just do a baffle board setup. My next question is, how good will it sound? right now, it's gonna set up like this. Dash speakers, and the 6X9's will be played through the deck, and the sub (a rockford fosgate punch sub) will be played through just my 700 Watt alpine amp. My last question, is if theres anyway to block the bass from my front speakers? I want to have the sub pumping most the bass, the 6X9's pumping some bass, but the dash speakers playing no bass. is there anyway to set that up?

Any help would be great!

Use a electrolytic capacitor in series with your front speakers to create a high pass filter.

10 uF will get you a cut-off of about 160 Hz @ -3 dB

(this is assuming you have one 4 ohm speaker per side)

If you want less bass than that, go with a smaller capacitor.

Do you have the formula for calculating this? I've always wondered if this poor mans crossover setup really worked well...

You can find several variations of formulas on the 'Net by typing in:

Series high pass filter

You'll get anything from the basic " fcutoff = 1/ 2piRC " to much more complex equations.

The capacitors do a fairly nice job. YOu'll find them on most coax speakers
filtering the tweeter.

Nothing beats an active cross-over for response curves, but for a few cents
you can't complain by using discrete components.

The only draw back is getting a capacitor to give you the cutoff you have
calculated. There are so many other variables like speaker wire length,
coil efficiency, speaker design that play into the curve. I'm lucky enough
to have the equipment to measure this 'stuff' and it's pretty scary how
speaker designs can vary.

Anyway, sorry for the long reply. Try the caps, you'll like it!

Sounds good! Except, where exactly would I find something like that, and how much do they normally cost?

Oh, and how exactly would I set it up?

Those caps would go inline on the positive wire going to the speaker. A "passive filter" is another name for them. Might want to keep that in mind when buying them... Best buy carries them I know, probably circuit city too. You haven't mentioned the head unit that you're going to be using. If it's a quality unit, it will have active crossovers built into it. If it's some cheap thing, you may want to consider getting a better unit (can't build a decent system with a poor HU). If your head unit has the ability, you don't need the filters.

You shoul be able to pick them up at most electronic supply stores, or just head out to a stereo shop and ask If they will sell some to you.

Cost is about a quarter each...maybe less if you are able to find surplus store.

Its a Sony Xplod GT Series Head-unit. CDX-GT610U. Has the front USB Thingy lol, and its 52WX4 for max output power.

I believe it's a pretty good head-unit by the looks of things. I dunno, whats your guys opinion, is it a good one or not? I got it for christmas from my bro so meh im happy with it no matter what.