Need input on dipolar sub design

[eStatic]

I'm planning to build a pair of dipolar subs this spring using the Adire Tumult drivers. The first problem is finding a way to power them that doesn't bust my budget too badly. The drivers and cabinet cost are going to eat almost all the $ allotted to the subs so the question is how much over budget I will have to go. I'm looking at the Lanzar VHC2000 and the Rockford Fosgate Power 1050S. These are both 2-channel amps capable of delivering about 550 watts into 2 ohms per channel. The Tumult is a dual 2-ohm VC driver capable of handling 1600W "per IEC 268-5." I've only found one definition of that standard and it sounds more like RMS than peak. But my ignorance leaves me with questions as to whether these solutions are too underpowered. Anyway I would need one amp for each speaker.

Lanzars amps 350.00 x 4 1400.00
power supply 600.00
---------------------------------------
$2000.00

Does anybody know a cheaper way to do this?

The other area of concern is construction. Given the heft and power of these puppies this is more like an engineering problem than a woodworker's cabinet design problem and I feel a bit out of my depth. At present my plan calls for building each cabinet as three independent components that are stacked one on top the other and bolted together on installation. Rough estimate on assembled weight per cabinet is 275lbs / 125 kilos. In the drawing attached the grey material is angle iron. Am looking for 7/8" / 22.2 mm oak plywood as the cabinet material. Any suggestions for improvments would be appreciated.

thanks

eStatic

[eStatic]

oops the horizontal views are in the wrong order.

[michael]

you said pair of subs, did you mean the 2 drivers being a pair or do you mean 2 boxes of 2 so having 4 tunults i the room

either way this system will move some serious air, but as for your question on ap, id be wanting at least 1 of those amps per pair, at 20Hz it takes 660w to reach xmax so this should be your minimum power goal, 550 will fit the bill though, but you would be better served throwing 1kw at each driver, this will give you plenty of headroom, and remember that dipole subs need HEAVY equalisation.
hope i helped somewhat

[michael]

forgot to finish my post
i recomend 32mm MDF, it is very strong, and not as $$$ thick ply. if you want you could put thin plt over the top of the MDF making it even stronger. 22mm is too thin for the tumults to mount on due to the huge stress that these woofer will put on anything they are near let alon screwed too...they are beasts

[eStatic]

michael wrote:
"you said pair of subs, did you mean the 2 drivers being a pair or do you mean 2 boxes of 2 so having 4 tunults i the room "

Uh... two subs, four drivers, 1100 watts per driver available. Linkwitz warns that it takes more umpf than one thinks.

I can't get 32mm MDF in a 75-mile radius of here--I've tried. And I need as small a footprint as I can possibly manage. I am planning to make the tops of the modules that hold the drivers out of two plies of 7/8" plywood laminated with epoxy for about 45mm total thickness to bolt to.

michael wrote:
"20Hz it takes 660w to reach xmax so this should be your minimum power goal,"

How did you get that? Not questioning its factuality, would just like to know what to read/study so I can do that my self.

thanks

eStatic

[Dave Jones]

Originally posted by eStatic
I'm planning to build a pair of dipolar subs this spring using the Adire Tumult drivers. ...

Does anybody know a cheaper way to do this?
eStatic

Do you own the drivers already? On the Linkwitz site there's a design using Peerless drivers that cost 30% of what the Tumults do.

http://www.linkwitzlab.com/woofer.htm
http://www.linkwitzlab.com/woofer3.htm

Always bear in mind that I know nothing.

[leadbelly]

Does anybody know a cheaper way to do this?

I don't know the history of how you settled on your driver choices and design, but I think you should read some of the dipole sub threads. There are some wicked designs suggested that could be built for less than $2K.

Also, you don't mention EQ devices, and I hope that you have accounted for that.

With that budget, I would definately be building a couple of planet10's push-push dipoles before anything else.

[tiroth]

If I were doing this I would use LCaudio's zappulse which is $150 and will do 500W into four ohms if you replace the filter caps (or just pony up the cash for the SE version). I would guess that you could even get about 1000W into 2 ohms given that these are bridgeable, but I would check. If so, you'd only need one amp per side, or two if you wanted to go crazy.

The power supply should not be too expensive. Very cheap would be to use four of ApexJr's clearance 24V/7A trannies per amp ($28) along with some of his $4 10,000uF 80V caps.

So possibly as cheap as $300+$56+filter caps? Much less than $2k. Depends on the peak to RMS load, but that setup with Steve's transformers is almost 700VA.

[Brendon]

Hey Leadbelly, I see you're located in Calgary too. Perhaps you'd be interested in an e-mail exchange?


Brendoncookatshaw.ca

[eStatic]

To Dave Jones -- I am familliar with that design ane those drivers and their not quite what I'm looking for.

leadbelly wrote:
"I don't know the history of how you settled on your driver choices and design, but I think you should read some of the dipole sub threads. "

Tumults are among the few for which I could find publish distortion specs. That's very important to me. If you can cite others I'd be most grateful.

The design was predicated on the requirement of a small footprint and the need to keep the weight of the largest single unit manageable.

I did several searches based on different key-word sets. I'll try some more.

leadbelly wrote:
"Also, you don't mention EQ devices, and I hope that you have accounted for that."

I've seen at least one passive 6 db/8ve schematic here that I think I could adapt to the I/O the impedances of my pre/power/ interface and knee freq. I'll definitely ask here before I go too far with that.

At your suggestion I'm doing searches for planet10's push-push dipoles right now. The only one I had come across was the tower of small drivers.

thanks

eStatic