Aero ports, what size and how many?

[bbbblaah]

Hey all,
I am currently using a slot port and want to change to aero ports. My box is roughly 5.25 cu without port displacement and I would like to tune around 32-34 hz. I am running 2 type r 12s.

So what size and how many ports should I use? I was thinking at least 2 and maybe 5"

Suggestions?

[Lakota]

Type of car? Depending on the shape of the box 3 4" ports will work well without having an insanely long port length. 4 4" or 2 6" would be optimal, but can often be hard to fit.

[bbbblaah]

It's in an extended cab truck. Wedge style box port firing up. Box is 20" tall outside. So if I go with 2 6" then I would probably have to bend it correct? Or is there a better option?

[bbbblaah]

Any other input, I like 2 6" aeros the best for port area purposes, but I do not know how to fit them in because they need to be around 24" long or something close to that. Should I buy some 90 degree bends and fit the rest in by bending it and having it go at the bottom of the box?

[Lakota]

3 4" ports should work just fine. Do subs forward port up.

[bbbblaah]

Cool thats how it is right now, I will def. do 3 4" I was just worried that it would not be enough port area. But I will do that, esp. since I was at the store and saw how much 90deg. bends cost. Is there a minimum space between the end of the port and the box wall that I need to maintain?

[mazdakid]

Keep it the ports width away from the back wall.

[Lakota]

I'd keep the gap over 4". People use the ports diameter as a rule of thumb, but I have found that 6 in ports can actually get pretty close to an object and not choke.

[bbbblaah]

Thanks, so psp-inc gives me a straight length req of 17.32" for 3 4" aeros. If my box is only 20" tall, will this gap be too small. If so, what should I do?

[thedukey42]

Box will be 4.75ft^3 @ 34Hz with 3 4" areo ports after port and sub displace (with areo ports at stock length, 17"). PSP recommends you keep atleast half the port width distance from the rear wall, so you should be just fine. It is best to keep it port distance from the back of the enclosure but it will work. Next time I suggest you design you box before you build it.

[bbbblaah]

Ok so I ordered the psp 4" flared ports. Is the 17" that is required the length from the ends of each flare, or the length of the tube before the flares? I am assuming to the end of each flare.

[Lakota]

Flare to flare.

[bbbblaah]

Cool, so from the box the whole assy. measures 18" from the end of each flare or the total length. So I should just cut off 1" from the straight tube correct?