Here are some images, may take me some time to measure inside vol etc. (please pardon the grabbing of first images that came up in google).
Left side of first pict is the top, amp plate goes there, forward facing driver in the middle, and face up driver in the bottom space (sharing the volume of the middle chamber).
Left side of first pict is the top, amp plate goes there, forward facing driver in the middle, and face up driver in the bottom space (sharing the volume of the middle chamber).
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I've worked with CSS drivers for a few projects and always been very impressed with them. The Trio12 models to max flat sealed in the app. 2 cu ft. available in the larger cabs, which is naturally a big plus. It also will run with the 250/350W amps without running out of Xmax, until the low teens. I envision them as being a supersub in a small box.
Since one will have to enlarge the hole for almost any driver (besides the ones sold by deep surplus), I figure the effort would be best served for a higher quality driver over one that's "just enough".
But, that's just me, certainly $42 is a very fair price.
I have a hard time thinking of 2x 12" in a sealed box as a real producer of sound below 20 hz, so I was planning on using the ApexJr smaller M&K amp panel which should have no issues even with the $42 speakers.
OTOH all the speaker holes are nice metal fittings, so it should be easy to try different drivers or switch to a different driver later on.
I'm just kind of anxious to make some noise sooner rather than later.
OTOH all the speaker holes are nice metal fittings, so it should be easy to try different drivers or switch to a different driver later on.
I'm just kind of anxious to make some noise sooner rather than later.
2x12" is equivalent to an 18" for displacement.... just how loud do we want to go here?
Anyway, I have been fiddling with the best way to shoehorn larger driver frames into the undersized cutouts (present on the cherry 2 cu ft. cabs, and the 2x12" cabs). One can:
Make a router jig
Use a drum sander
Find a midget-frame woofer
I'll try the drum sander soon, picked one up today. The smaller framed woofers, well, per Parts Express, some of the goldwoods have a 12" frame 11" cutout like the smaller box holes. Unfortunately, sealed box size for what seems the best match to me is 8 ft^3. One could, however, toss an isobaric pair into the 2x12" box, with some care and finagling. Firing into the manifold (which I would line with absorbtion for further low pass filtering) could work exceedingly well, having lots of built-in low pass filtering (can you say: distortion filter?)
How big is the cutout on the cherry cabs? The cutout on the maple cabinets is 12 1/4".
Badman: I'm totally set up for making a router template to enlarge the holes if you need one. I've got several routers, collar set, two circle guides, bearing bits, table saw, etc, etc. Fixture alignment could be the headlock sockets on the cabinets.
Thinking somewhat outside of the box for a minute........One could bolt a number of these together back to back and front to front to make a large volume cabinet. Of course, the drivers would be either pointing at the floor, the ceiling, or both if the resulting cabinet is positioned vertically. This could be done without molesting the cabinets by popping out the T-nuts in alternating cabinets and screwing the cabinets together with thin weather stripping between them.
I snagged 15 of the maple cabs for some experimentation.
Here are a few pics of the maple sub cabinets for those who haven't seen them:
Badman: I'm totally set up for making a router template to enlarge the holes if you need one. I've got several routers, collar set, two circle guides, bearing bits, table saw, etc, etc. Fixture alignment could be the headlock sockets on the cabinets.
Thinking somewhat outside of the box for a minute........One could bolt a number of these together back to back and front to front to make a large volume cabinet. Of course, the drivers would be either pointing at the floor, the ceiling, or both if the resulting cabinet is positioned vertically. This could be done without molesting the cabinets by popping out the T-nuts in alternating cabinets and screwing the cabinets together with thin weather stripping between them.
I snagged 15 of the maple cabs for some experimentation.
Here are a few pics of the maple sub cabinets for those who haven't seen them:
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Knowing what I know now, I wish I'd gone for maple. I like the cherry but the cutouts are undersized, at 12" OD 11" Through hole (also true of the dual sub cab I measured). The bolting cabs together is a good idea, I've been kicking it around too. One could fairly easily also jigsaw some cutouts and stack them vertically if 4 ft wasn't enough.
I may take you up on the jig assembly. Sounds like you have a better idea of how to go about it than I do. I was going to do an 11" circle to align it, and a set of slots to router through. There were still some difficulties in my mind though. I'll try the sanding drum route first though.
I don't think that you're limited to 4 ft3 when bolting back-to-back. You could probably do back-to-back then front to front etc for any length stack that you want, all without molesting the factory cabinets. Odd numbers of cabinets will have a back and a front showing and even numbers of cabinets bolted together will have fronts exposed.
I have a ServoDrive Contrabass kit (waiting on doing the box), loud and low is the hard trick.
Not sure how much it might help, but if finding an amp plate to fit the dual boxes doesn't work out, an external amp could be used and the amp space could be opened to the rest of the chamber.
Certainly true, I'm thinking more of the form factor and potential line effects. On the other hand.... if you lined all of yours together you could have a 15hz (or thereabouts) quarterwave pipe!
Appreciate the offer of help with an expansion template. The Grilles don't fit the cherry cabs so can't use that as a template base. I'm going to give the drum sander a quick go 'round, I'm usually pretty good freehand.
Best!
Jeff
Attached are 4 pics. They show the drum sander, the gasketing, the velcro baffle fixing, and the marking of the inner lip (you can see a sharpie in the box, and the blackened MDF edge).
Don't forget to wear a mask and clean the dust out of cab (leafblower works well). Keep some rubbing alcohol and paper towel to clean any marker slips. I cut the pegs off with a veneer saw. The #8 machine screws are not very large but work well with some drivers. With modern drivers, you may wish to apply more fastener points and (T nut/ hurricane nut /wood insert/superglue in a screw-tapped hole). The vintage JBLs I'm using only have 4 holes, and fit a #8 screw well.
Don't forget to wear a mask and clean the dust out of cab (leafblower works well). Keep some rubbing alcohol and paper towel to clean any marker slips. I cut the pegs off with a veneer saw. The #8 machine screws are not very large but work well with some drivers. With modern drivers, you may wish to apply more fastener points and (T nut/ hurricane nut /wood insert/superglue in a screw-tapped hole). The vintage JBLs I'm using only have 4 holes, and fit a #8 screw well.
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Pushmepullyu
Reworked a pair of the push pull cabs this weekend. One magnet side fires into the manifold, one cone side. Limited testing so far but they seem very very VERY impressive. Signal processing functions are via Reckhorn B-1, the amp is a cheap old Yamaha I have, and the drivers are modded JBL 122A.
The 122A is about 40 years old, I refoamed them, and after testing and finding that they'd lost their alnico magnetic charge (higher Qes), I coated to cone to add mass and optimize them for OBs. They work well in these too.
Reworked a pair of the push pull cabs this weekend. One magnet side fires into the manifold, one cone side. Limited testing so far but they seem very very VERY impressive. Signal processing functions are via Reckhorn B-1, the amp is a cheap old Yamaha I have, and the drivers are modded JBL 122A.
The 122A is about 40 years old, I refoamed them, and after testing and finding that they'd lost their alnico magnetic charge (higher Qes), I coated to cone to add mass and optimize them for OBs. They work well in these too.
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I'm taking my son to Howies Gameshack either today or one of the Friday's soon, so I think I may stop by Deepsurplus and get a couple of the $42 woofers they sell for the dual boxes. I bought the last small M&K plate amp that ApexJr had, and its supposed to fit the dual box, so I might actually have sound before much longer.
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