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help request for a little p.a. and 260

midijaymidijay Posts: 9
I have optimized the inputs and the outputs of the driverack in optimal way, the meters of the driverack exactly do what the meters of my mixer allen&heath are doing.
now I would want your help to optimize the driverack with my p.a.
unfortunately I don't have any information on the components climbed on in the boxes, because' the retailer has removed the labels on all the loudspeakers.

the 2 tops climb on 2 cones 15\" and 1 driver 2\" (the photo is attached)
the 4 sub climb one cone 15\" ciare mod.pw396 (photo too)

the tops are powered by a labgruppen 2000c in stereo at 8ohm
every couple of sub is powered by a crest cc1800 in bridge at 4 ohms

can someone suggest me equalizations settings and other settings???(delay for alignment of the cones..limiter..or any settings to improve my sound)

thanks in advance to all those that will help me to have a good sound!


  • GadgetGadget Posts: 4,915
    Ok, well I was hoping to find those speakers somewhere, but it's not totally necessary...

    Those subs appear to be a mini horn loaded sub, of small size.. the reason I mention that is that the volume of the chamber, and the length of the transmission line affect the hipass... In this case I'm going to say that since we don't know the particulars, and until they are measured, that a safe bet might be 40HZ BW 18, certainly no lower than 35 hz...As for the lopass.. I'd start @ 100 hz (you didn't specify, but the tops I assume are internal passive crossover, fullrange speakers...) maybe as high as 120 hz LR24. The maybe a few hz spread for clarity in the crossover region...Let the tops go to 'out' which means whatever they can do...

    As for the delay, well.. I'm guessing a horn length of 3-4 feet, and @ .885 ms/foot that's 2.5-3.5 feet.. roughly... the LR 24 filter has a design delay of about 7.5 ms (all processors do, some more some less) so add the two together and 10-11.5 ms delay.. that would be the tops...you would delay. to allow the sound to get out of the subs.. add to that any distance you put between the front of the horn and the cone bottom of the 15\" on the subs...I have provided a more accurate method in the FAQ section and you really should go there and read the entire READ ME FIRST BEFORE POSTING.. section for clarity on the Driverack and itt's nuances and application.

    If you have the RTA mic use the method I used in this thread:
    http://www.dbxpro.com/forum/viewtopic.p ... highlight=
    Note that the RTA mic is only about 4-6 feet, 8 feet tops from the speaker... on axis with the mic in the horns coverage pattern...

    Make sure to get a good gain structure.. and I'd use a 9 volt battery and make sure all the cones are going the same direction with a plus to plus and negative to negative of the speakers. you could also put the speakers side by side and make sure the sound ADDS and doesn't subtract form each other .. indicating a phase reversal...

    As for Equalization.. hmmm no way to tell over the internet...sorry...

  • thanks for your great help gadget!!
    I want only to ask you some explanation:
    the delay must be apply to the tops or to the subwoofers?
    do I give equalization around the point of crossover?
    if I must give eq...to which frequency?
    there and' a post where it speaks of as to use 260 in rta fashions?

    the dimensions of the subwoofers are : 23x23x15 inch
    the tops are in fullrange and they have an internal crossover .

    i have also read this post:
    my crest cc 1800 have this value:
    Input CMRR @ 1 kHz > -75 dB
    Gain selectable between x40 (32 dB) and x20 (26 dB)

    i found this value in driverack amps settings for the qsc rmx1450
    Voltage Gain x40 (32 dB)

    is the same of my amp...
    do you think can i use setting of others amplifier on my crest cc1800??

    if not...how can i discover the right value of the input sensibility (knobs) of my amplifier??

    i'm asking this because i ear some hissss in my tops..and i think this is the result of a not good settings on the knobs level of my labgruppen 2000c (tops amp)

    so: my crestaudio cc1800 voltage gain 32db
    labgruppen 2000c voltage gain 38db

    assuming my amps knobs are all at full , if i set on driverack -6db in input gain of the labgruppen channels..is it right??
    this because i don't know how set -6db in labgrubben knobs respect the knobs of the crestaudio

    thanks for all!!
  • uppppp!!
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