So I wanna build a box..

[dsmbasshead]

So I currently have a pre-fab ported box housing 2 JBL GT5-10s SVC 4 ohms (275 rms each) pushed by RF R500-1 amp(537 rms at 2 ohms[subs are wired parallel for 2 ohm impedence].) I originally wanted to build a box when I bought the subs and amp but do to lack of knowledge and tools, I went with a pre-fab. Now that I know more and have a buddy that has some box building experience and tools, I wanna give it a shot. Heres my plan. A 31.5"(w)x13.5"(l)x13.5"(h) (internal 30"x12"x12") box with two 3"x9.93" flared ports. Box would be about 37 hz. The recomended volume per woofer is 1.25 cubes so the 30"12"12" would give me 2.5(for 2 subs). What Im kinda stuck on is whether its 1.25 total(including displacement of port and woofer) or 1.25 plus displacement. Here(CLICK) is the Spec sheet, please tell me what you think(scroll down to ported/vented.) If it is 2.5(for both) including the displacement, then heres what I sketched up...

So I guess what Im asking is 1. is the 1.25 including displacement or not and 2. does that design look good(as in correct)?

[Skullz]

The 2.50 is gross volume meaning you haven't yet included the displacements, net is after all displacements are done. With a .10 sub displacement with subs and ports your net volume is 2.32 with a tuning of 35.39hz on the design you have now.

EDIT: With the ports the way you have them drawn will act a wall between the subs so they'll get minimum influence from each other.

Edited September 22, 2010 by Skullz

[dsmbasshead]

The 2.50 is gross volume meaning you haven't yet included the displacements, net is after all displacements are done. With a .10 sub displacement per sub and ports your net volume is 2.32 with a tuning of 35.39hz on the design you have now.

EDIT: With the ports the way you have them drawn will act a wall between the subs so they'll get minimum influence from each other.

So based on the JBL spec sheet, it is gross? So i should try to make the total volume 2.7? and also what you said about ports, is that a bad thing? should I move them?

[Skullz]

The box you drew up should be fine for those subs, just go ahead make it and bang away. That .18 displacement won't make or break it on how it sounds or acts as long as your close enough.

[dsmbasshead]

The box you drew up should be fine for those subs, just go ahead make it and bang away. That .18 displacement won't make or break it on how it sounds or acts as long as your close enough.

so the ports are good where theyre at? and I dont need to redesign for more airspace?

[dsmbasshead]

and also 2 questions... when it says port length, is that from the very front to the very back or just the tube(between the flares) and which would be better the face of the subs firing toward the back (away from the front of the vehical) or up at the hatch glass?

[Skullz]

Port length is from end to end and have the subs and ports firing the same way. Yes the way you have it drawn is perfectly fine for what your doing.

[dsmbasshead]

Port length is from end to end and have the subs and ports firing the same way. Yes the way you have it drawn is perfectly fine for what your doing.

So all i need to do is get two of THESE then trim it down 9.92 inches total? And as far as the firing...which would be better?

[Skullz]

Round it out to 10" which is what i did to come up with the tuning on the box of 35hz. So all you need to do is cut each one 10" long and glue them in and seal them as you have it pictured. Your starting to over think this and its not hard just do as your wanting the way it is in the pic and leave it at that.

[dsmbasshead]

So overview...the 31.5" x 13.5" x 13.5" design is good, the two 3" ports in the middle are fine and the length of the ports, with connectors, tubing and flares included is 10". Ohh and which is better, rearfiring or upfiring? Sorry for the redundancy.

Edited September 22, 2010 by dsmbasshead