opinions on DIY sub based on driver

Discussion in 'Archived Threads 2001-2004' started by Jay Stewart, Jan 1, 2002.

  1. Jay Stewart

    Jay Stewart Auditioning

    May 14, 2000
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    I did some searching and couldn't find where this had been discussed here before, so here goes.
    Until about a week ago I was heavy into car audio, and I have sold most of my stuff. What is left (read: cannot sell quickly) are my old subs. They are two JL Audio 12W6 subs. My goal is to use just one of them for my theater system, and keep the other for a future mad scientist style project.
    Here is the data sheet from their website (beware, it's a PDF):
    I plan to temporarily power the sub with my old Kenwood receiver which is 100x2. I've tested it bridged mono and it works just fine. Eventually I'll get an AVA250 to power the sub. These subs are a weird DVC 6 ohm arrangement. So I'll end up with a 12 ohm sub, or a 3 ohm when I'm done. (Is the AVA250 OK with a 3 ohm load?)
    My question is in what sort of box to make. I have an 8 foot section of sonotube (24") that I planned on using with a Shiva. Looking at the specs on my driver, it looks like it would want a fairly small box. I'm also concerned about the sonotube holding up, with my car audio applications, you need a really stout box for these subs.
    My experience has typically been with small sealed enclosures, with lots of power behind them. I'm not opposed to either using the sonotube, or building a regular square box out of MDF. Ported or not ported doesn't make a difference, I just want something that sounds good. My woodworking skills are most definitely not spectacular, but I can manage a square box, and I have my wood working neighbor to help so that it looks nice.
    Size of the sub is not an issue, my wife was already prepared for a 6' tall sono sub. I listen mostly to TV/DVD, but also like to hear music on my system. The future (and permanent) location of the theater is 12' wide x 18' long.
    Any suggestions, recommendations, pointers, etc. I've read most of the sonosub links I can find, but as I said, I'm not 100% sure if that is the right solution for me.
    Thanks a bunch,
  2. Vince Bray

    Vince Bray Stunt Coordinator

    Oct 4, 2000
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    That really isn't a bad driver. I got pretty good results from unibox using a 200 liter (net after driver, port etc) tuned to 18hz. A 6" port 25" long is required. This gave very flat response to right at 20hz, -3db at 18hz.
    With a 24" sonotube, that would be a cylinder about 27" plus the height of endcaps, feet, etc. You could use smaller sonotube and use dual 4" ports to get a taller, more slender sub.
    BTW you might do best with that amp running each coil on one amp channel instead of bridging the amp. Oh, and whatever you do, don't bridge the amp into the coils in parallel, that would make an extra-crispy kenwood [​IMG]

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