question about isobaric loading

[jbiddle.com]

so quick question when running and isobaric loaded enclosure it says size may be cut in half but what would happen if you ran the full size enclosure say 3 cubes ported to 30hz with isobaric loaded 12s? what would this accomplish or hurt

[john253a]

youll defeat the purpose of the reason you chose to iso in the first place

[FutureFuzz 26]

what style Iso did you have in mind?

[White Lightning]

Isobaric is not actually an enclosure type but a woofer loading method. Isobaric loading can be used in conjunction with any of the enclosure types, except perhaps infinite baffle. Isobaric loading consists of two woofers coupled together by a short enclosure which is only long enough to prevent the two woofers from striking one another. The woofers may be mounted face to face, back to back or front to back. However it is important to have the woofers firing in phase with one another. In order to accomplish this with the woofers firing front to front or back to back one of the woofers speaker leads must be reversed with respect to the other woofer.

Isobaric loading is usually used when space is at a premium or a maximum number of woofers wish to be used in a certain volume of space. By isobarically loading the woofers, a box of only half the size of a one woofer box is needed. For example, if a 12" woofer requires a two cubic foot box, the same 12" woofer isobarically loaded only requires a one cubic foot box. The cost of this design, other than doubling the woofer cost, is a reduction in the subwoofer system efficiency by three decibels (if both woofers are given the same power as a single woofer), which is equivalent to halving the amplifier power.

[BobbyG2]

I would've thought that isobaric would increase the efficiency, rather than reducing it, since there's two motors helping each other out.

[Tarball]

so quick question when running and isobaric loaded enclosure it says size may be cut in half but what would happen if you ran the full size enclosure say 3 cubes ported to 30hz with isobaric loaded 12s? what would this accomplish or hurt

To answer your question:

You will cause your sub to bottom out. Same as if you put a single 12 in a box twice as large as it is designed to be in (assuming you are running it at RMS power). This problem would be exaggerated under tuning point. I have smoked the @#$% out of a pair of tens like that, but it was for scientific purposes so its OK.

[Tarball]

I would've thought that isobaric would increase the efficiency, rather than reducing it, since there's two motors helping each other out.

You are loosing efficiency compared to traditionally loading the two drivers due to 1/2 the cone area moving air. Loading isobaric would be potentially "louder" than a single drive application due to the increased power handling (instead of 1 drive @ 500wrms you now have 2 @ 500wrms = 1000wrms - for example).

[jbiddle.com]

i was thinking isobaric loaded 6th order for two jl 12w3v3 for my 240sx hatchback. how would i acomplish this?? any ideas

[jbiddle.com]

so i cant run 2 12s iso in 2 cubes safely

[CleanSierra]

I'm running 2 10s in a push/pull ISO setup and they sound amazing in 1.5 cubes tuned to 33Hz. The one sub is ASS out inverted and the other is in the box. I have a 3/4" MDF ring between the two in order to seal them. The enclosure I have is efficient as can be and these low power handling 10s sound amazing and get loud.