i have 2 8ohm kicker compvr 18" subs [from 1999] in seperate sealed chambers on a power acoustik Lt/1920 [880w rms] i want to get louder problem is i dont have space for another box so i was think of getting two more of these subs and using a isobarik design to net more volume subs are rated for a 2.2 to 3.3cu ft box they are in a 2.25 cu.ft [each] box. so will i get twice the volume if i do this.i am also adding a second pa amp. i know i need a new alt. ect.ect. but can any1 tell of their experiences or link me to a site where i can read up on benifits or problems that may occur
Replies (4)
cplkittle on 01/7/2005 03:52:31
You have the right idea by using an isobaric design for limited space. This is a paragraph from my article in the DIY section (overview of enclosure designs).
"Isobaric or dual drivers can be used with any enclosure. There are multiple ways to set up an isobaric configuration. One is to enclose them within the same airspace and set one of the drivers 180 degrees out of phase. Another is to mount them together in an enclosure with an air cavity between them, in this setup the first driver is pushing into a box which the second is facing out of. The third and most common isobaric configuration is to mount them face to face with minimal airspace, but enough so that they are not touching, and wire them 180 degrees out of phase. The idea behind this is that one driver pushes while the other pulls, lightening the load on each speaker. Advantages to this are improved bass response. Bass is said to be tighter, faster, and more accurate. Vas of the driver is cut in half, as well as the volume of the enclosure.
Isobaric enclosures are used where size is an issue, or where more accurate bass is more important than a lot of bass. Disadvantages include wasted amplifier power, and efficiency is down 3dB over that of a single driver."
The designs for this type as with many other are only limited to your imagination. From my experience, the best setup would be the face to face, push pull type. Use minimal airspace between the drivers, but allow for excursion.
Bigeazy4387 on 01/7/2005 10:15:27
thanx alot man i heard you mention "with minimal airspcae but provide room for excursion" can i just mount the directly on top of each other they only move 11mm?
cplkittle on 01/10/2005 07:08:54
it depends on the sub really. If the surrounds touch or are very close to touching, use a 3/4" MDF ring to space them. Since they are moving the same direction when facing each other (one in the other out) they shouldn't touch, but a little space dosen't make that much of a difference.
Bigeazy4387 on 01/11/2005 11:50:09
thanx alot for the info i am prob just gonna sell them but that will help me later
Replies (4)
cplkittle on 01/7/2005 03:52:31
You have the right idea by using an isobaric design for limited space. This is a paragraph from my article in the DIY section (overview of enclosure designs).
"Isobaric or dual drivers can be used with any enclosure. There are multiple ways to set up an isobaric configuration. One is to enclose them within the same airspace and set one of the drivers 180 degrees out of phase. Another is to mount them together in an enclosure with an air cavity between them, in this setup the first driver is pushing into a box which the second is facing out of. The third and most common isobaric configuration is to mount them face to face with minimal airspace, but enough so that they are not touching, and wire them 180 degrees out of phase. The idea behind this is that one driver pushes while the other pulls, lightening the load on each speaker. Advantages to this are improved bass response. Bass is said to be tighter, faster, and more accurate. Vas of the driver is cut in half, as well as the volume of the enclosure.
Isobaric enclosures are used where size is an issue, or where more accurate bass is more important than a lot of bass. Disadvantages include wasted amplifier power, and efficiency is down 3dB over that of a single driver."
The designs for this type as with many other are only limited to your imagination. From my experience, the best setup would be the face to face, push pull type. Use minimal airspace between the drivers, but allow for excursion.
Bigeazy4387 on 01/7/2005 10:15:27
thanx alot man i heard you mention "with minimal airspcae but provide room for excursion" can i just mount the directly on top of each other they only move 11mm?
cplkittle on 01/10/2005 07:08:54
it depends on the sub really. If the surrounds touch or are very close to touching, use a 3/4" MDF ring to space them. Since they are moving the same direction when facing each other (one in the other out) they shouldn't touch, but a little space dosen't make that much of a difference.
Bigeazy4387 on 01/11/2005 11:50:09
thanx alot for the info i am prob just gonna sell them but that will help me later
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