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tuned enclosures

Discussion in 'Amps and Cabs [BG]' started by Gabu, Mar 29, 2001.

  1. Gabu


    Jan 2, 2001
    Lake Elsinore, CA
    What are the measurements you use to consider a speaker "tuned" to a cab?

    The items I generally here shot back and forth are:

    size of the box (volume)
    size and depth of ports
    size of the speaker
    wattage rating of speaker (RMS/peak)
    size of Voice coil

    Does it follow that if speaker a is the same size, wattage and has the same size voice coil as speaker b then it will also be "tuned" to the box? If not what else am I missing?
  2. MikeyD


    Sep 9, 2000
    No, it is much more complicated than that. See http://www.kbapps.com/audiodesign/calculators/index.htm. You have to deal with the Thiele-Small parameters of the system (volume equivalence or compliance, mechanical impedance, electrical impedance, Q - the "peakiness" of response or damping ratio, resonant freq., etc.). This is why designing bass enclosures is not that simple. Even using these parameters alone will not guarantee success, but they can yield reasonable results. I believe Joris has done a lot of this kind of design, so you might seek his advice on it. If you are truly interested in it, I'd recommend doing a lot of reading on it first.
    - Mike
  3. Gabu


    Jan 2, 2001
    Lake Elsinore, CA
    Thanks for the quick response. I will read that right now. I am not looking into designing a box. I just want to add good speakers to a existing box. I have had a hard time finding the model number of the speakers that originally belonged there so I am kinda trying to reinvent the wheel as it were.
  4. MikeyD


    Sep 9, 2000
    I understand that situation. A few years back, the woofers in my AR bookshelf speakers died (the foam surrounds rotted out), so I bought some replacements from Parts Express. I tried as best as I could to find something I thought would work well, and it turned out they were decent. These were acoustic suspension speakers (closed boxes, with no porting), BTW.

    Recently I have considered upgrading the drivers in my Carvin 2x10 with ones that will handle more power and be more efficient. I think I found some that might work, and I used the calculator in the link I gave before to confirm it. I still have a margin of doubt, though. Well, don't let my previous comments deter you, but go into it prepared, with eyes wide open - or at least with lots of money (in case you need to try a bunch of different drivers to find a good match!).

    You could try using the design calculator I pointed out to find a driver that you *think* might work. Then with the T-S parameters for the drivers and box dimensions, Joris might be willing to confirm whether it would be a good choice. He has offered such help to others in the past. It's worth asking him. Good luck!

    - Mike
  5. Hey Garth Brooks. :D (That's what I think whenever I see your name.)

    Are you talking about the sweet 2x15 cab you just got? That thing looked like it was a copy of a Sunn 2x15 cab with the center horn-type port. The Peavey probably came with Black Widow 15's for Bass. You can order these from a Peavey dealer. The Sunn came with JBL D-140F's, supposedly one of the holy grails of bass speakers. These would probably work well in that cab, but they are expensive as sin. The Peavey Black Widows I'd read on the WeberVST board were a copy of the JBL's, so it would make sense that the cabinet is probably a close copy.

    I'd at least check the prices on the Peavey Black Widows at a local dealer. You could probably talk to Peavey and put in the correct speakers that were originally in that cab, and you'll get good results with little risk of having a mismatch. I'd probably go with the 1501DT-4 and wire in series for 8 ohms, just cause I always go for the classic old sound. Here's the spec sheet on the Black Widow family:

    I'm using an Altec 421 in a Peavey single 15 enclosure with great results, although they aren't high power like the Peavey BW or the JBL 140's.


  6. Gabu


    Jan 2, 2001
    Lake Elsinore, CA
    I appreciate all the help.

    I got this Peavey 2x15 for $100 and while it sounded decent with the wifeys keyboard it didn't do too well for bass. It seemed way too light and when I opened it up... tadah!! Fisher speakers.

    I am not compaining though, the enclosure is in good shape so I think $100 is fair anyways. You guys have been great help!!
  7. ubersam


    Oct 12, 2000
    no, actually it's Gorgonzola. or was it Gargantuan? :D


    g- check out my reply in your thread re: your 2x15 peavey. as throbbinnut mentioned, i'm also thinking that your 2x15 originally came with 15" BWs. i'm also wondering how carvin's 15s would work in that box.
  8. Gabu


    Jan 2, 2001
    Lake Elsinore, CA
    That's Mr. Goober Brukowski to you Ubie! ;) Carvins are a good idea. I am going to be measuring the cab and using that to attempt to learn what speaker would be tuned to it. Then I will know what to get.

    If I can't figure it out that way, then I will try to get the peavey speakers on the chance that they should work best with a peavey cab... time will tell.

    Anyone know where black widows can be bought by themselves and (hopefully) approximately how much they go for?

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