I just got 2 12" subs, and want to throw them in a ported box. Looking at the specs, i can put EACH one in a 1.75 cubic ft box, meaning i can probably fit two in the trunk. Am i going to notice any difference if i put them both in seperate boxes as opposed to putting them both in one ported box.

Also, these subs run rms 750, but i'll be feeding each around 550....can i still go with the manufacturer specs on enclosure sizes, or am i going to have to go another route since i'm not too close to how much power the sub can handle?

 

which subs do you have?

 

The amount of power you are feeding the sub does not affect its T-S parameters... so don't change the box size.

You get max power handling by putting a woofer in a single enclosure. That said, it's easier to port a larger volume to a low frequency than a smaller volume of air... the port area and length are larger for smaller boxes.

Without knowing what speakers you have, I would still say that you sound like a good candidate for a 3.5 cu ft box with two 12" in it. Remember that port displacement does not count towards box volume (neither does woofer displacement).

I would take the porting freq recommended by the manufacturer and also get the driver displacement as recommended by the manufacturer, and then use somebody's enclosure calculator and figure the port you need for tuning at that note . I'd use a 4" port made from Home depot PVC.

 

i got some treo ssi's
their recommended enclosure for ported is (per sub)
1.75 cu ft net F3=28hz
16 sq in vent, 16.5 in long

I don't know what 3 in F3 is, but it gives box size, tuning freq, and port size and length.
That's pretty much all i need to know to make a ported box, right? I was going to try n figure it out from there.

 

Hmmm. F3 is the frequency where the box is 3dB down... essentially how low the box plays.

Fb is the tuning freq of the box.

If you increase a volume, you change the size of the port required to tune it to a particular freq. I don't have SW on this PC but maybe you can get BassMech to figure you a box 7 cu ft tuned to 30 or so...