Home dbx User Forum dbx Archive Threads DriverRack PA & DriveRack PA+ PA General Discussion

driverack pa+ with peavey qw4 speakers

MLMMLM Posts: 0
edited April 2016 in PA General Discussion

I am new to this forum. I just bought a driverack pa+ and am overwhelmed with all of the options available. I am biamping Peavey qw4 speakers with bridged qsc 3002 for the lows and a stereo behringer ep4000 for the highs. Could someone help me with the set up? The presets for jbl sound awful with the peavey. I set the crossover at 1200 hz and it sounds pretty good, but I know that it would sound much better if it was optomized.




  • GadgetGadget Posts: 4,915
    The internal Passive crossover is set @ 1200hz, the driver can go as low as 500 hz but that is not recommended... You can go lower with a steep crossover point and an active crossover... no lower than 900 hz I would think for driver longevity reasons.

    That said lets settle on 1050hz to minimize the beaming since it's a 15": midrange and the driver has a 4" voice coil.

    Set up a custom 2X4 all custom amps and speakers.

    Now for the problem....you can't bridge either amp on the lows... that would be a 2 ohm load, and in bridged mode that will not fly with either amp as they are not stable at that low an impedance...to properly power these you should have 2 of the EP4000's running bridged, one per speaker, as it is you'll want to switch the 4000 in stereo to the lows and you'll only have 1200 watts per speaker...barely enough to run them as mid high cabs...

    So, you are VERY under powered for the lows, ESPECIALLY if your going fullrange and have too much power for the hi's... so, your not going to get great sound at any volume with this setup... what say you?
  • MLMMLM Posts: 0

    thanks for your input. I may have not been clear on my setup. The Qw4's in biamp mode are rated at 2400W program and have an impedance of 4 ohms. The highs are rated at 200 W program with an impedance of 8 ohms. The QSC plx 3002 is rated at 3000 watts bridged at 4 ohms, so technically I may be a little overpowered for the lows. The Behringer EP 4000 is rated at 550 W rms per channel (run stereo) @ 1% thd at 8 ohms so I am almost triple the rated power for the highs. So I am running 2 qsc amps and 1 behringer amp. I have to be very careful with the highs. You are right that the passive crossover for the qw4 is set at 1200 hz and the speakers sound pretty good when I set the active crossover (pa+) at that level. I read a post by Marty McCann from Peavey who suggested 1800 hz as an active crossover point. There are just so many other things to set (type of crossover, what level, db pad etc) that were not around when I was playing 30 years ago, that I feel I need some help in optomizing my system. I am not a very good singer so I need all the help I can get!

    One other question. If I set the eq using auto eq with the rta mic, does that mean I don't have to set the geq or the peq because it will be overridden by the auto eq?

    I really appreciate the sound community's willingness to help each other out!

  • GadgetGadget Posts: 4,915
    Ok good.. that's what I said, you need another amp for the lows..

    That's not too much power for the lows either.. the rating is 1200 watts RMS, 2400 program and 4800 peak, so you are pretty good with 3000 watts..

    I don't understand Marty saying that about 1800hz, that's higher than I set my SP2's with a 1.75" XT driver??? and I have used these for YEARS with no problem

    I suggest...

    HPF 55Hz BW18
    LPF 1050hz LR24
    for the lows
    HPF 1050hz LR24

    Set up a 2X4 and use the hi and low outs

    As for the EQ's you can use the GEQ/and Auto EQ for tuning the speakers and the PEQ's for room EQ

    Read the FAQ section on the main page, also read "Start Here"

    Make sure you read the latest Auto EQ thread in the FAQ's as things have changed...

    The reason I say use 1050hz is anything above about 700-800 hz on a 15" woofer can start to cause beaming, an undesirable artifact that can raise hell with your audience...and NO amount of EQ can change that... but try both if you doubt what I"m telling you... it's easy to do!
  • MLMMLM Posts: 0

    I tried your settings and they sounded much better than the 1800 xover point. It was much louder and I wonder if that was influencing me. I have read that I need to input a delay to align the drivers. Is this true? What would your recommendations be?


  • GadgetGadget Posts: 4,915
    Peavy is pretty close mouthed about anything, usually the delay is predicated on the distance from the bottom of the cone on the woofer and the diaphragm on the horn. The nominal factor is .885 ms/ foot, but lets just use 1ms/foot...so, 6" difference is .50ms, 3" is .25ms, remember to delay the one that is in front of the other to allow time for the other to catch up...

    The only way other than measurement, and that includes FFT measurement systems that CAN measure that, is to play a tone @ the crossover frequency... reverse the polarity of either of the speaker components (but only one)... play the tone and sweep the delay till you get maximum attenuation (quietest tone) at the crossover point (it won't be even close to total, but a lul) use that as the delay factor.
  • Gadget

    I have a set of QW4 tops and a set dual QW18 subs. I have a CS 4080 on the subs and a CS4080 on the top. Im running a 2way system. Have should I set my driverack?
  • DraDra Posts: 3,777
    This thread is 4 years old.

    Subs - 45hz BW18 - 100hz LR24
    Tops - 100hz LR24
Sign In or Register to comment.