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Single Amp for hi & & low?

djconroydjconroy Posts: 5
edited April 2007 in PA General Discussion
I know it's unconventional, but I'm currently stuck with a single PLX3602 power amp, and need to power 2 Yamaha S115V tops (500w program/8ohm) and in some situations 1 or 2 Yamaha SW118 subs (600w program/8ohm each).

Would it be possible to send stereo out from the mixer and have the hi left go to ch1 for the tops and low left go to ch2 for the subs?

If it is possible, how would I configure the dbx PA?


  • Should not be a problem. Just set the DRPA to work biamped (hi and low output). use only the left channel connections. be sure to check in the manual for your amp that it can run at least as low impedance speakers as 4 ohms (I would be very suprised if it can't) 2 ohms is OK also. make up some leads to run the mid-hi speaker in parallel (two 8 ohms in parallel become one 4 ohm load at the amp). do the same for the subs.
    Running different signals through the left and right channels of the amp will not be a problem.
    Other than those changes, everything else should work as normal, so you'll need to work out the other settings through the normal method (gain structure, EQ's, limiters etc).
  • DraDra Posts: 3,844
    Do you mean stereo as in L & R? You'll need to sum the signal at some point or lose half the material. No problem running 2 tops on one side and 2 subs on the other. Actually the amp matches quite well with the power requirements of the speakers.

  • Sorry, you will need to mix down to mono before putting in through left channel - if all inputs are mono, just leave pan in the middle. For stereo inputs, feed each channel into a mono input with pan centered. No worries..
  • djconroydjconroy Posts: 5
    Thanks for the advice! I'll be trying this later today. Wanted to make sure I had all my ducks in a row before I start hooking things up wildly.

    One question - If I have a stereo source feeding into the CD/Tape In on my mixer, what do I need to do with that source?
  • DraDra Posts: 3,844
    What is your set-up?
    CD player (RCA out)?
    DJ mixer (RCA in)?
    DJ mixer (XLR out)?
    More? Other?

  • DraDra Posts: 3,844
    Does you mixer have a \"sum out\" or a \"left / mono out\"?

  • djconroydjconroy Posts: 5
    I've got a laptop, running a Hercules DJ console as an audio interface, hooked to a DJ mixer which controls time coded vinyls.

    Right now the DJ mixer is feeding into my main mixer via 2x1/4's on a stereo channel... But I could also use the CD input channel as well depending on which cable type I use (RCA's vs 1/4's).

    The mixer, a Behringer UB1222-FX Pro (my last piece of cheap gear, but it's never given me grief) I've got doesn't have a summed main out, but I was thinking perhaps I could use the summed monitor out as the main out?

    Of course, I'm always looking for a chance to upgrade... Are the Mackie 1604-VLZ's as delicate as I've read? That would give me a summed main out.
  • DraDra Posts: 3,844
    Sounds like you have a lot of options of where to \"Y\" the signal. Any one of them may do. Unless Check your software. You might can do it there with properties, preferences, customize, etc.
    I'm not familiar with Mackie.
    Just checked out the B'ringer. No meter for monitor. Wouldn't do that.
    Using your existing L/R 1/4\" cables, L into 9/10 (R) and R into 11/12 (R), done. You can leave the pan at center, then it won't matter which output you use. This is like the old days, before manufacturers started adding stereo inputs on boards to not kill 2 channels if you needed stereo trax. Kind of a DUGH moment there.

    Good luck

  • wolfgongwolfgong Posts: 74
    Gents -

    If I understand this correctly the challenge/problem is having only one amp, thus two amp channels and we want to route the tops mix through ch1 and the subs mix through ch2. So we need to Y at some point so we don't lose left or right channel program material.

    If that is the case it would be much cleaner to Y inside the PA digital space. You can do this at the beginning of the output stream by selecting A&B as input to that output.

    Try this:
    PA Inputs channels 1&2
    mixer Left out ->>- PA chA input
    mixer right out ->>-PA chB input

    PA Outputs 1-6
    PA six output channels
    A&B ->>- output 1 ->>- Tops
    A&B ->>- output 2 ->>- Subs

    This will not be stereo, but will allow combined mix (L&R) routing to both tops and subs while allowing seperate gain structure to tops and subs without losing left and right program material. It will also be cleaner than doing a Y outside the PA in digital form.

    This is a little challenging to communicate via text so if you need clarification just post something. A block diagram of the inputs and outputs is on page 31 section 3.5 of your user manual. If you don't have it handy it can be downloaded from this link. ftp://ftp.dbxpro.com/pub/PDFs/Manuals/English/260Manual.pdf

    PS The mackie will do a mono out, but I believe this will be cleaner from a noise perspective and from a phase cancellation perspective.
  • wolfgongwolfgong Posts: 74
    My mistake. I've given a dr260 answer for a PA config. Sorry.
  • GadgetGadget Posts: 4,915
    I need some time to take this whole thing in but there is something goofy here...I have been away and need some time to process this whole thing...
  • djconroydjconroy Posts: 5
    Hey Gadget, any more input?
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