Gotten a couple questions about the 12w7. So, I’ll answer them publicly.
You can use whatever amp you want; but it has to be able to go down to the rated 3ohm of the 12w7. There are plenty of amps that do this. Here’s a short list:
http://www.thebuttkicker.com/home_theater/products/bka1000-4a.htm
http://www.parts-express.com//pe/showdetl.cfm?&Partnumber=300-806
http://www.zzounds.com/item--BEHEP2500
Just depends on how much power you want to push it with. It's rated for 750w rms, but I was planning to have about 1kw on tap.
When I modeled this up with bass box pro, it seemed 4ft^3 and 25hz tuning yielded the best compromise and was flat down to the mid 20’s before rolling off (as you would expect from a tuned enclosure).
You could easily build a sealed enclosure, but for HT use, I prefer ported (vented, tuned, whatever you want to call it).
I asked Manville Smith about using this sub in HT tuned to 20hz and this is what he said:
Okay... to get good output out of a vented W7 as a home subwoofer you will need between 500-1000 watts. We use 1.5 kW on our f112 home subwoofer (which uses a modified 12W7), but it is a very small sealed enclosure and needs the power to overcome its inefficiency. Even 500W will get very nice, clean output as a home theater or music subwoofer.
As a theater sub, I'm slightly concerned about your proposed 20 Hz tuning frequency. For 99% of material this will be just fine, but there are a handful of very demanding soundtracks that are plumbing the depths of bass well into the 10 Hz region. This can cause distress to a vented sub tuned to 20 Hz if you don't apply some protection to it in the form of an infrasonic filter (basically a steep, 24dB/oct. high pass filter just below tuning). You could also play around with your box alignment and try to cheat the tuning a little lower. If you can get it down to 15 Hz, you will probably be safe. It might cost some box volume to keep it flat, but if that's acceptable you will have a pretty spectacular subwoofer with absolutely subterranean response.
Unlike a car, we don't get a lot of help from the room (although we do get some at very low frequencies) in a home setup. In a small room, you can expect some lift below 30 Hz and you should take that into account in your sub's response if you can. In a larger space (like an open plan house) the response will be much flatter so the sub needs to do all the work down low.
Placement of a subwoofer is also hypercritical in a home setup. The space is large enough for modal behavior to occur in the sub-bass range and the placement of the sub and the listening seat(s) is critical. Using multiple subs, distributed around the room, is really the only way to get smooth bass over a large seating area, but good results can be achieved for one or two seats with a single sub if you experiment with placement and use some judicious (CUT ONLY) equalization.
You're never going to get the visceral sub-bass you get in car audio, but a well-executed home subwoofer system can take any home speaker system to an entirely new level of performance and is a very worthwhile project.
Have fun.
Manville Smith
JL Audio, Inc.
So, here’s a solid chance to have a ‘gotham-esque’ performance for a fraction of the cost. If you picked up a second one of these and put it at the back of your HT you’d have some SERIOUS output. Which was my original plan, but my car audio project has taken the driver’s seat, and the fact that I won’t have a house until May has pushed back plans and necessities for HT.
Now, for the IDmax, You can get substantial low end out of this and a clean upper end, too. For the HT effect, 5 ft^3 and 22hz tuning yield the best results, imo. Same amps above could be used, but this is a DVC 2 ohm sub, so can be wired for 4 ohms.
For anyone who wants either of these for HT, I’ve got a 4”x10” (approximate) aeroport that I’ll toss in the box for you to use if you want.
Prices:
12w7 = $325 + shipping (paypal)
IDmax 12” = 225 + shipping
If anyone wants to talk to me over the phone, PM me and I’ll give you my #.
Thanks,
Erin
