Enclosure size question

[Flyin11]

I bought 2 JL Audio 12W1v2 subwoofers last week and needed a enclosure. Been trying to find one around town pretty cheap and close to exact requirements for the recommended cubic space for a sealed enslosure which is 1.25 for these. I couldn't find anything anywhere close. I only wanted to spend $60.00 max for a box so I went to the flea market in town and the guy had 0 dual 12" enclosures. I found 1 left at a Audio store near me called Audio One. The volume in it is 1.4 per chamber. The audio guy told me I would be just fine and to put about a 1/4 of poly-fil in each chamber. Now, the 1.4 does not include the driver displacement and size of the bottom of the sub after it is installed. So, I think after adding that into account I will be just fine cause I didn't want to lose a lot of the bass sound I got from the ported enclosure I had after I go to sealed. Was the audio guy correct? Adding Poly-fil will help decrease the size of the chambers? I'm a little worried that I might have made a mistake. It's a great quality done box compare to what I was looking at on Ebay but that one I was looking at was $40.00 less and had a 1.3cu foot size. I just want to make the right decision about the enclosure.

[ca90ss]

The polyfill will make the enclosure seem larger. If you want to make the enclosure smaller just glue some blocks of wood inside the enclosure.

[Flyin11]

Wonder why he was telling me to use the poly-fil? I think he said something about changing the frequency with it so that it will hit at the right response...

[I Am An Idiot]

Have you put the speakers in the enclosure and listened to them yet?

[ppia600]

The poly fill will make the woofer "think" its in a larger enclosure, so the frequency response will be lower and it also helps cancel some unwanted internal resonance. But actually does subtract some of the volume from the box.
I prefer to use carpet underlayment foam for my boxes, its more dense and allows the box size calculation to be more accurate. I glue it to the sides with the same glue they use to attach it to the concrete foundation. That glue doesn't break down the foam, so it stays attached firmly to the box sides.

[Flyin11]

Originally posted by I Am An Idiot
Have you put the speakers in the enclosure and listened to them yet?

Haven't tried them yet cause I'm still waiting on the speakers to be delivered...Hopefully around Tuesday or Wednesday

The poly fill will make the woofer "think" its in a larger enclosure, so the frequency response will be lower and it also helps cancel some unwanted internal resonance. But actually does subtract some of the volume from the box.
I prefer to use carpet underlayment foam for my boxes, its more dense and allows the box size calculation to be more accurate. I glue it to the sides with the same glue they use to attach it to the concrete foundation. That glue doesn't break down the foam, so it stays attached firmly to the box sides.

I might look into that....It's just the regular foam padding for carpet like in your house?

[ppia600]

Originally posted by Flyin11


Haven't tried them yet cause I'm still waiting on the speakers to be delivered...Hopefully around Tuesday or Wednesday



I might look into that....It's just the regular foam padding for carpet like in your house?

Yeah, and they have different thcknesses you can get. It is chopped recycled looking stuff with mixed colors.

[Flyin11]

I'm figuring this...Box is 1.4 cubic ft per chamber...The Displacement of the Driver of the sub is listed as 0.035 cu. ft...So:

1.400 Cu ft - 0.035 cu ft= 1.365 cu ft...Rounded off, 1.37 cubic ft.

There speaker page says 1.25 cu ft for a selaed enclosure (thinking this is the minimu size)...After speaker is in, it will be 1.37...That's a difference of 0.115 cu ft. Which I don't think that's a lot to worry about. It will probably give me a bit more bass response.

Anyone know what 0.115 cu ft. is in inches? I'm thinking about trying some shipping foam from my old job to maybe knock it down to required specs...

[I Am An Idiot]

198.72 cubic inches But I really think you will be fine without adding anything to your box. That would be a piece of material 10 x 10 x 2 inches thick if you INSIST on adding something.

[ca90ss]

Originally posted by Flyin11

Anyone know what 0.115 cu ft. is in inches? I'm thinking about trying some shipping foam from my old job to maybe knock it down to required specs...

198.72in^3...I think

edit:
^^^beat me to it