Box specs

[Hydrastas 10+ year member]

The main thing that i need work on in car audio is working with ported boxes. The specs for the sub i have going ported is 6cuft of airspace with 3 ports 4" cir by 10" in length. While i wait to get wood to build this box, what could i do to a 2cufoot sealed box to make it ported? Should i just try experimenting with port diameters, or is there a way to know how big the ports should be with less airspace?

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[Hydrastas 10+ year member]

What im basically asking is there anything that can be done to a 2cufoot sealed box to increase the output by making certain sized ports knowing that it needs a 6cufoot box with 3 ports 4"diamter and 10"long. By the way i've got polyfil in the sealed box, wouldn't that make the driver see like 20-30% more airspace? So instead of 2cufeet it would be more like 2.5cufeet.

 

[Hydrastas 10+ year member]

ok so i took the 2cuft sealed box and drilled 96 .4in diameter holes in the top rear. I figure thats right at 12.05cu inches of surface area. When i play the 40hz test tone i can hear a major difference from before the holes were drilled. Now for making them 10 inches in length, what about taking some 10" cardboard tubes a little to big for the holes and shove them in there?

 

[Flipx99 5,000+ posts]

Did you really drill 96 holes in your box?

 

[Flipx99 5,000+ posts]

There is no way that I know to turn 2 cf into 6 cf without more wood.

 

[Hydrastas 10+ year member]

Yeah i didn't have any spare blades for my jigsaw. One idea that comes to mind is maybe if i take the other sub and make it isobaric. Wouldn't that make it like a 4cuft box?

 

[Flipx99 5,000+ posts]

I would just stop and wait...Those things are a little complicated and I am too drink to explain.

 

[Hydrastas 10+ year member]

Ok heres a question thats bothering me. If i were to make a 12 cubic foot bandpass box and put one of my 15" subs into it would it be able to make more bass than 2 of the same 15s in separate 2cuft boxes??

 

[Volenti 10+ year member]

Ok heres a question thats bothering me. If i were to make a 12 cubic foot bandpass box and put one of my 15" subs into it would it be able to make more bass than 2 of the same 15s in separate 2cuft boxes??

Over a given frequency bandwidth? yes.

But 12cubes should big enough for a triple chamber BP using both drivers. Post the drivers specs and I'll give you an example.

 

[Hydrastas 10+ year member]

The drivers are american bass dx15s. 700w max 350w rms.

 

[Hydrastas 10+ year member]

I did some more messing around and had one sub in the box with the 96 holes in it and held the other sub with my hands about an inch apart from the sub in the box. While playing a steady 40 hz test tone i'd move the one sub back and forth to see if there was a difference and im no genius but while watching my hula girl on the dash i could tell a significant difference in the way she swayed back and forth while i held the sub an inch away from the one in the box. btw this is with both subs out of phase with each other. Volume wise i couldn't tell much of a difference however, but the vibrations seemed greator while in an isobaric state, so should i go with mounting the sub like that or what?

 

[Hydrastas 10+ year member]

That was also without the air between the subs sealed up, if i were to mount the sub i would make it so the air between both sub fronts was sealed off.