Snail Shell for 2 12"

[Iso187]

I previosuly had my 2 12" Perfects in a 1.88 sealed box(each), then later (to free up some space in my trunk) decided to build Decwares infmaous DeathboxII. I was VERY impressed with the deathbox 10, so I guessed the 12" version would have twice the output. The key is I want to use BOTH the woofers. I iso'ed them in the Deathbox and... sounded very nice and clean, but greatly lacked the SPL that the previously sealed enclosure had. As a last resourt I would go to a ported due to the large volume needed. I understand the SS is also a large enclosure, but if it is supposed to have the sound quality of a sealed, w/ the volume of a vented, I am willing to test it out first. But as previouslt stated, i would like to use BOTH the woofers. My question to experienced builders, I have many hours research on the enclosure and have found the dimensions for construstion for a REXXX. For those that dont know the story, supposive P4S was underpaying, or ripping off an employee (cirrect me if im wrong) and that employee started leaking some info onthe boxes construction. He claimed the the box stays basicly the same except fot the small enclosure which the driver is mounted. This is calculated by the Qts and Vas of the woofer. If its close to the REXXX's that design would wook for your woofer. Well, my Infinity's arent close, but I was wondering if possible to either (also wanted input on which would be better) Iso load my woofers, or I thought design it with the 2 woofers sharing that inner enclosue air space. I thought I read about there being a "Dual Shot" that uses 2 12" but I cant seem to find any info on them. One last thing, with this enclosure, how would the calculations for the inner enclosure be done?! Anyone with previous knowled of building this enclosure, or just more experience than myself I would GREATLY appreciate their input. Thanks.

[flaevor]

This type of enclosure seems to be some version of a Quater Wave resonator enclosure. (The strange thing is that it seems to have a compression chamber like a horn and then a line with varying cross sectional area, that niether tapers nor widens uniformly.)

that means if you really want to design a quality enclosure you would first read everything you can about Transmission lines and then download mathcad and licence the worksheets from Martin J King and start calculating different geometries based on your TS parameters.

Since it would seem that it is for your car you would maybe want to take into acount cabin gain when figuring out where to roll off the response in your simulations.

Hope that helps or makes sense.

[Iso187]

ok, first i would like to thank for responding with your info. I have looked into quarter wave designs, and get kinda lost. Also from my understanding they are relatively larger enclosure which makes them very difficult for car audio. I have posted on SEVERAL forums, and either noone likes me, of just has no valuble input to help me. So I return. After more research, and reading older posts on countless forums, I came across a person who claimed that i could utilise this enclosure with two woofers (Doubleshot) by removing the "A" boards. So this is what I came across. My question, I wouldnt think this design to be universal, so would it be wise to run my BBP software to calculate my woofers parameters and design my enclosure around that? Or anyone who has had experinces with this enclosure type, I could love to hear feedback!

[Iso187]

I aslo tried getting MathCad with no success. You have any links?

[flaevor]

The snail shell thing was the subject of heated debates and flaming by people using less than scientific arguments last I saw.

Therefore no one wants to touch it.

There is an older version of MathCad availble through a link on the quarterwave.com website last I checked. It's not the ideal version, but it should work.

I personally have yet to pay MJK for the sheets and as a result have zero experience and cannot help you any further.