Push pull sub bass cabs

Hi

i did about ten years ago a clamshell design with two Fane 15B in a bandpass enclosure. Size was 50x50x57 cm and it was flat from about
33 Hz to 120, sounded absolutely marvelous, very fast response and really low. the only (and the biggest) problem was that is was missing absolute SPL, which meant that it wasnt made for live purposes unless stacking a ridiculous amount of subs, which wasnt an issue at this time budgetwise. if you are interested, i can try to get out old infos.
i may even have the plot i did at this time, with a neutrik system (no sim).
basically you should be able to make a sim with winISD, which will give you already an idea.

I've built nothing but push-pull subs for the last 20 years or so. Dual and quad 12s, dual 18s, and lots and lots of dual 15s. 

None were clamshell, that is a waste of time, money, efficiency, and output.

The box design must be specific to the T/S parameters of the driver you want to use.

Edited by _djk_

Kind of like this:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=73392 75215&category=47094&rd=1

This was a box EV came out with after I talked with one of their engineers at a trade show about 20 years ago.

EV showed me the light in 1974 with the Interface A, an SBB4 alignment with a Q=2 filter ahead of the amplifier, so it became a B6.

All my best vented designs were assisted B6 or C6 after that.

Around 1980 a friend of mine that was a FOH engineer with dB Sound turned me on to the (then) unreleased MTL4 design. I thought it was cool, but didn't like the short x-max 18s (I don't like 18s in general), and didn't want to have to use a fork lift to move it.

I built a half-height design with two 15s facing each other on a narrow slot. On one of the pair I mounted the drivers push-pull (the reversed driver hooked up out-of-phase electrically).

This sounded so different I thought it sounded funny (at first).

It sounded funny because it had no distortion. It made a large 40hz bass horn sound distorted in comparison. I had Eminence custom make me a large x-max 15 that had the same volume displacement as a good 18 (and went lower).

Now, of course, we see push-pull boxes from EAW, TAD, etc, although I have not seen any exactly the same as the ones I made.

I took an engineering type job (doing L-band RF stuff for the military) about seven years ago and haven't really made anything much since then. I've been thinking it may be time for another production run as some of my old used boxes are trading hands for more than I sold them for new.

Edited by _djk_

I was looking for designs for somthing like these :-

http://www.smartsounddirect.com/content/ProductDetails.asp?P roductID=SSD1013

 

It's just a simple ported cab with one driver reverse mounted and inset. If you can use a pencil,ruler,win isd and a calculator(for volume) then just design one yourself.

You won't get high sensitivity from compound loading. In reality,you won't do a whole lot better than 6th order bandpass. The only reason you would want to compound load is if you needed REALLY small boxes. If you can make a pair of 6th order cabs(space wise) you will get as much output as possible.You would even do ok from large ported boxes.

The compound cab might be able to get a little lower but at the expense of output(power divided by 2 drivers and you can only 'hear' one). If you were to build a large compound cab,driver control(excursion) would be a little limited and you will run out of cone travel early with low power(and output)