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Improving punch in a cheap 15-1 ..and Q on posting specs

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  • Improving punch in a cheap 15-1 ..and Q on posting specs

    A few years back i got some Goldwood GW-1558 woofers and build an undersized sealed cabinet crossed at 2K Hz and cheap tweeters and I used them to make prerecorded music loud enough to accompany with drums, guitar amps, etc.
    It worked well enough because they provide a lot of thump, but tweeters blew and i replaced them with higher wattage RS piezo, which don't go as low and aren't as loud.
    Recently i want to use them more as PA cabs, so i added horns to fill in the upper mids.
    To see if i can get some punch in the upper bass i used 2x2's and shims for a bit of temporary bracing, and filling to about 80%.
    The bass seems tighter, but still lacking what I get by running the woofer in parallel with other drivers (the crossover has jumpers for either 4 or 8 ohm woofer). I've tried a few different speakers (2 different 12" guitar speakers, old Newcomb 8" PA column, some rear channels, bookshelf speaks, etc.) and it makes me want to add a driver....
    I was thinking maybe a 6 1/2", as i have some JBL2600 consumer cabs and it would give me a chance to see how they sound in there too. I'd like to put up specs, etc for some advice, but is there a format to follow for posting specs, etc?

  • #2
    Re: Improving punch in a cheap 15-1 ..and Q on posting specs

    Originally posted by Phil Lloyd View Post
    The bass seems tighter, but still lacking what I get by running the woofer in parallel with other drivers ...
    There is a saying "No replacement for Displacement". Double the drivers and each driver's excursion requirement is halved. The driver operates closer to it most linear range with a theoretical 6db boost in the bass.

    I'd like to put up specs, etc for some advice, but is there a format to follow for posting specs, etc
    T/S specs ( which are small signal specs ) are mandatory, as well as excursion data.
    Beyond that is Klippel ( or large signal measurement ).
    We may not be using "punch" in the same manner, but critical aspects to what I consider "punch" are revealed in Klippel data.
    "Not a Speaker Designer - Not even on the Internet"
    “Pride is your greatest enemy, humility is your greatest friend.”
    "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

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    • #3
      Re: Improving punch in a cheap 15-1 ..and Q on posting specs

      Thanks Sydney,
      I bought a 6-1/2" driver ( http://www.parts-express.com/pe/show...number=292-210

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      • #4
        Re: Improving punch in a cheap 15-1 ..and Q on posting specs

        You are going to have a lot of trouble getting a 15 with a SPL of 95 to play right with a single 6.5 with an SPL of 88. That represents over 4X the power needed to get the same output.

        'punch' often means mid-bass. One thing you can try, is changing the tuning of the box to 60Hz or so. You will lose most to all of your real low end, but if punch is what you are after, it might help. You would also need to High pass the 15 if you did that.

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        • #5
          Re: Improving punch in a cheap 15-1 ..and Q on posting specs

          Thanks AMC,
          I was only able to get a somewhat even balance loud sound by seperately amping the 6.5.
          I noticed the lower SPL, and guess the big drop in output (when hooked in parallel to the 15") is due to the lower efficiency.
          I'll keep those 6.5s in the JBL cabs.
          The GW1558 wants a huge box - mine is just over half of PEbox's recommended volume.
          I made a sealed box as PEbox recommended, even though it is small.
          I need to brace it, and ... i am wondering about the tuning you mentioned.
          As yet it's just a hollow box, and i'd need to enclose the other woofer i suppose, plus a filter...
          I'd actually like to try that - i am used to how this sounds and would like to do one cabinet and compare the two ...
          but i've never tried tuning a box either (other than primitive experiments with car speakers - lol)
          How would i go about tuning the box?

          ... I was also looking at crossovers again. I was thinking of adding just a band-pass filter in line with whatever mid woofer i try.
          I guess a 3-way crossover would be best ... but too costly at the moment.
          Last edited by Phil Lloyd; 08-14-2012, 07:25 AM.

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