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drive rack pa low mid high

mitchiemashamitchiemasha Posts: 26
edited June 2009 in PA General Discussion
Just wanted to run this by people.

Although the outputs are low/ mid/ high, I some times change this.

Using the ability to over lap cross over points I can set the mid section to drive a full range dual 15/horn cab & use the low, high outputs to set a standard bass bin, mid/tops crossed over at 80hz setup.

I was told by the retailer I couldn't do this, although it clearly works.

I've used the mid out to feed a full range system what used its own eq/cross over, say like a bose 802 system used as room fill, whilst using the low & high as if it was a 2 way system for the dance floor. setting the mid to fullrange, the low to low and the high to mid/high.

I'm currently running a drive rack with the mid as an alternative mid/high out aswell as the high been a mid/high out. due to the rear wall speakers been different from the dance floor speakers. They have different tunings and require different gains.

There is loads more reasons why I could think you might want to do this.

As it's overlooked and I've not seen it mentioned I was wondering what the pro drive rack users out there had to say about it.

Comments

  • DraDra Posts: 3,777
    Yes, it has been discussed here before (buried deep in some thread, I'm sure). The main uses are for power stearing with multi cabs set-ups and multiple zone outputs. The retailer may have been referring to the overlap in the low region actually cause loss of spl.

    DRA
  • The retailer may have been referring to the overlap in the low region actually cause loss of spl.

    I showed him and he was suprised, he had only used the wizard to set up settings. he believed moving, say the mid high cross over would change the cross over point for the highest mid point and the lowest high point. instead of you having to change both individualy to match.
    actually cause loss of spl

    Which brings me to a question I asked on the peavey site about a full range dual cab which uses the lower 15\" for bass what I stand on top of an 18\" bass cab. after all the reading I have done I cant deciede the best way. I'm still awaiting an answer, possibly the question was too complicated for the users, who knows.

    http://forums.peavey.com/viewtopic.php?f=26&t=7740

    thats the question.

    So you would not recomend to ever over lap the Xovers, is the output of the drive rack effected as it wont be calculating the curves correctly at overlap points? or is it simply because the speakers coupled together would be creating crazy cancelations with each other. I have been reading all about that.

    I venue I have worked is a very long bar. The front sound system is an old martin 1, bass and mid/tops with it's own controller. The rear sound system is new (bar was extended, practicly another room that bleeds through) this relies on the drive rack for the cross over. I would use the mid out to feed full range to the martin controller. Then use the high and low outs with the highs, high pass set to 80hz and the lows low pass set to 80hz. Is that a bad idea or do the cross overs work completly idependantly in the drive rack. is it only the speakers themselves that would cause the problems.

    sorry for the long posts. thank you for helping.
  • DraDra Posts: 3,777
    80hz is not a good x-over point due to the fact that it sits right on top of the kick drum. I like to turn off the top cabs and play music w/ vocals through the sub. Raise the filter until it sounds bad (unnatural) then lower it until sound nice (natural). Generally speaking you'll have only a few resonances from vocals, but probably none. The lower the x-over the better the subs will sound, with a trade off in mid clarity. The higher the subs go the tops will sound better, but the subs won't sound as good. 90-120hz is pretty typical. For my system, 100hz works great (12\" tops).

    DRA
  • GadgetGadget Posts: 4,915
    Now for my system, I have a drive rack and want to tune my hisys 4 rig. Peavey spek (I think) usealy recomend arround 100-125hz low pass for their 118 subs, unlike my JBL system, 80hz. If I use the hisys 4's with the Peavey subs wouldn't it be much better to have my xover set much lower down near the 80hz rating?

    That depends on a number of factors...the most important is how much power you have... If your able to power the tops with the recommended power 2 to 4 times x the rated power (say they were 400 watt that would be 400, 800, 1600 watts(instantaneous peak)(or continuous, program, peak) then yes 80 hz would be fine. HOWEVER the less power you have the higher you should cross the lo mids in...up to about 120 hz where the subs start getting honky, and nasaly...

    Actually if you'd asked here we always tell folks that the Driverack can drive full range or partial range with any output...so you could drive 6 fullrange speakers... or 5 fullrange and a sub...etc...
    Usealy I run the hisys 4's full range, no prossesing. with the 118 bins set 125hz low pass. but, I've been reading up loads and I'm stuck on what cancelations might be occuring. Especialy due to the cone pointing downwards and producing similar frequencies as the bass bin.

    This IS a bad idea...and yes there are going to be cancellations in the overlap area...think of it this way, the sub puts out a 79hz kick drum 1st harmonic note..the tops lower 15\" puts out the same note ... but because of the fact that it is on top and behind the 18\" and some other factors like crossover delay, the note is 1/4 wavelength out of phase...the notes cancel...NO 1st harmonic and a duddy sounding kick... read this it's similar:

    http://www.peavey.com/support/technotes ... lation.cfm

    Think now of the myriad of notes flying around and the possibilities for cancellation increase exponentially..

    You will see SOME overlap in CROSSOVER points, but they are calculated to work WITH the slope to make a more \"MUSICAL\" crossover...

    I was thinking as a start to set like this,
    118's high pass around 35hz as the low cut off, a low pass at 80hz (xover point). hisys 4's, high pass at 80hz with a small low pass slope at 18khz...

    I think you would be better to move that xover to 40 hz-45hz... but try both.. it's simple to do I think it will help the low end definition since those subs use a 3\" voice coil 18\" (I think)
    'm still concerned though, as to my from 80hz to ??? (bottom HS4 driver) frequencies. The cone is pointing down over, not front facing. will I be losing these frequencies on the bass cab as the top HS4 driver isnt producing them. meaning having the cross over higher up or overlapping the 2 ouput ranges (I've read is bad) would be better after all.

    No, the low the frequency, the less directional the sound becomes... the directional frequencies are left to the top speakers in the cab...

    Gadget
  • Thank you, thats solved all my doubts. I only ran the hisys 4 cab full range ontop of the bin because I had no drive rack. No ability to set the cross over.

    As for those boundry cancelation, oh no, massive problem in the club. Will up load a picture later. I will add though, I didn't place the bass bin enclosure there. I'm going to need a jig saw.

    I've got a tech god coming down on tuesday to help my finalize the system, hopefuly he will be suprised on what I've learned through you guys, thanks again.

    a lot of the topics I've been dicussing are about different systems I work on or with. just thought I would clear it up, incase ppl where getting confused. 1 I use SA (xti amps), 2 have a drive rack and another no prossesing at all.
  • I would still like to know the xover point between the lower 15\" and the higher 15\" in the hisys 4. hopefuly ppl at pv will have me the answer soon.
    the most important is how much power you have

    lots - qsc 3602; xs1200; rmx2450, 1850HD, 1450; xti 2000, 2x 1000's. I keep getting good deals then selling off my weeker amps.

    Nothing compared to pro hire companies but I think for a daft dj, who I am thats some power. Not that they are used on the same systems.

    I've got 1 old PV left, just slogging its arse out in 1 bar I work. Simply because the managers believe that a maplins pro sound sound system is good. We wont even get started on that.

    The club I'm tunning. had xs1200 xs900 and 3 pv amps, although many have faults.

    pv1500 - ddt coming in way earlier on 1 side than the other, when receiving matched feed. powering 4 8ohm mid tops pv imps, underpowered.

    xs900 - double vodka red bull. driving 4 logic mid tops

    pv2600 - channel b totaly dead, sold it on ebay, faulty. Crown csl1400 temp replacement. underpower for subs. peavey dual 15's

    xs1200 - works fine, powering 2 logic subs, 1 driver down.

    pv900 - right channel dj monitor, left channel mc monitor. I've added this for them.
  • 80hz is not a good x-over point due to the fact that it sits right on top of the kick drum. I like to turn off the top cabs and play music w/ vocals through the sub. Raise the filter until it sounds bad (unnatural) then lower it until sound nice (natural). Generally speaking you'll have only a few resonances from vocals, but probably none. The lower the x-over the better the subs will sound, with a trade off in mid clarity. The higher the subs go the tops will sound better, but the subs won't sound as good. 90-120hz is pretty typical. For my system, 100hz works great (12\" tops).

    Totaly missed that and it was my next question. excelent. whilst playing earlier I was setting different 3 way xovers and thought well i'm cutting up the frequencies here and doing damage to the essential parts to our style of music.
  • DraDra Posts: 3,777
    If the Hisys cabs are designed (loosely used) like the SP4 and similar cabs, then the bottom 15 has a coil to add a high cut filter at about 300hz (ish). This is to limit mid freq cancellations inside the enclosure.

    DRA
  • You can tell I got all excited there. 3 posts in a row. I normaly dont get much help.

    thanks guys.
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