I have already done that. I would like some other help from all of you though other than ISD. Unibox won't work. Has anybody built a sealed eclosure with this driver? This is my first time and I would like some links to people's sites with projects posted. I tried with ISD and with a 5.56ft3 enclosure, I got 30Hz. I want the sub to go to 25Hz. Is this going to be a problem? Does ISD take in account polyfill or placement in a room? If it does, tell me how. I would like to have some help though. Links would be great for your sealed enclosure project. Thanks.
A 5.56cubic foot sealed enclosure is way to big for any of the 12" drivers that are worth purchasing IMO. For something like the Shiva, Dayton DVC, or Titanic you'll be looking at more 1.5-2cubic feet.
When you say "I got 30hz." what do you mean? Using which sub, with how much power? Personally, if you can go over 5cubic feet then I would look at a bass reflex design using a port. Say, with the Dayton DVC something around 3-3.5 cubic feet tuned to 22-25hz. That should give you pretty good output and decent extension to boot.
You should also try doing a search, you'll find LOTS of threads exactly like yours where questions have already been answered by people much smarter than me.
Oh, and here are some links to subwoofer projects Link Removed And here...follow the navigation bar on the left.
That should give you a start. And one last thing. What do you mean "unibox won't work?"
Dan Hine
Shawn doesn't have Excel, so he can't use Unibox. I also think that he's calculated his internal volume incorrectly. He stated he could go with an 20x20x24 enclosure. If those are external dimensions then his true internal volume is more like 4.46ft^3. He'll get a pretty low Qtc with heavy stuffing.
Also, 30Hz is his Fb. I've explained in an email to him that he'll still get plenty of output below 25Hz due to room gain, although in his email to me he specifically was talking about the Shiva MKIII.
I have the Dayton DVC 12" in a 1.9ft^3 sealed enclosure heavily stuffed at the shop and it mates up very well with our demo pair of A/V-1+'s.
Oops, I hit the wrong key. Anyway, thanks for the links Dan. That is exactly what I am looking for. Brian, I've sent you an email. Thanks everyone for helping the newbie.
How the heck do you get 4.54 ft^3 for the SVS 20-39?
Start with a 40 inch height. Subtract 1 inch for the base plate. Subtract 2 inches for the legs. Subtract 2 inches for the endcaps. That's 35 inches internal height. Maybe less if they're using thicker endcaps.
The cross-sectional internal area is 201 in^2. So you get a gross 7035in^3 volume. That's only 4.07 ft^3. Subtract about 200 in^3 for the port and 180 in^3 for the driver and you're at 6655 in^3 or 3.85 ft^3.