soudboard problems!

Discussion in 'Live Sound [BG]' started by Secret Journey, Oct 9, 2011.


  1. Secret Journey

    Secret Journey

    Aug 29, 2009
    Hey all, Worship band was practicing last night, things were going well. I run the sound at practice. Our church has a 6 year old 24 channel mackie system, two power amps, one for mains, one for monitors.
    Three vox, bass, one acoustic guitar(martin, and I cut the lows on it) Korg triton keyboard, and an electric (run direct via sans amp GT2, into a sans amp "acoustic" DI to house.)
    Ok last night we are practicing, when the monitors went out. Hmm I thought. I shut system down and restarted. They came back on. Then a while later they went off again. Restarted system and they stayed on.
    Today sunday morning service, ppl said the mains went out, then came back on. Not sure if that was accurate or not, I did not notice any loss in the monitors though.
    Please help whats going on? Are there gremlins in the system? Thanks for any advice! Did I overload the system? Usually we are just three vox, bass, and acoustic. So I did something wrong, just not sure what.
     
  2. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Check the batteries. j/k.

    Without knowing all the gear details, it almost sounds as if some form of amp protection is kicking in. The fact that the system fires right up when re-booted leads me in that direction. Can you tell us a little more about the power amps, attenuator settings, etc.? Gear that is truly broken does not repair itself...but, then again, prayers for the ill, infirmed, and hospitalized may have spilled over onto the PA rig.

    I'll burn in the bad place for that one.

    Riis
     
  3. Muzoid

    Muzoid

    Feb 12, 2011
    Canada!
    Sounds like the amps have an auto shut-down when they are peaked for too long (or overheating).

    Have someone watch the amps peak lights, you may be just running them too hot.
     
  4. Secret Journey

    Secret Journey

    Aug 29, 2009
    Ok noob reply of the day.. How do I not run the amps too hot?
     
  5. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    That's a good question...one that even supposedly "experienced" soundmen can't answer. First off...

    *What amps are you using?

    *Where are the attenuators set (two adjustment knobs on front in most cases)?

    *Have you removed all air flow obstacles (just in case we're dealing with a true thermal problem)?

    *How familar are you with mixer function interaction, including mic channels, input trim, EQ, etc.?

    Riis
     
  6. Muzoid

    Muzoid

    Feb 12, 2011
    Canada!
    Sorry...I should have elaborated....are the amps in enclosed racks that don't allow for sufficient air flow?

    Like asked above, give amp(s) info.
     
  7. Secret Journey

    Secret Journey

    Aug 29, 2009
    What amps are you using? I am pretty sure they are QSC. My own bass rig for playing out is a qsc 2450, and always have enough room. But i think the church one is the 1450? I think

    *Where are the attenuators set (two adjustment knobs on front in most cases)?I believe they are set 2/3 the way up. ( i think) will stop by the church this week to see.

    *Have you removed all air flow obstacles (just in case we're dealing with a true thermal problem)?No, and I noticed they were dusty

    *How familar are you with mixer function interaction, including mic channels, input trim, EQ, etc.? I let my ears, and others be the guide. I am not formally trained, it is a hobby of mine, and I believe I get a good sound. So in fairness i think i am somewhat familiar with the mixing interaction. Thanks again for taking the time to help!
     
  8. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Good...I use the 1450's and 2450's exclusively. The 1450 pushes ~280 watts / per side 8 ohm so it's not overly powerful but still a decent plant. It's been my experience that an attenuator setting of 10:30-11:00 provides a nice, smooth, clip-free response with my main sliders set @ unity -0-. This holds true only if the mixer is not clipping @ -0-, otherwise, all bets are off. There's a couple of neat procedures available to best match the mixer output with any given power amp. If interested, PM me. I'm only semi-pro in this arena, as well.

    BTW, what Mackie mixer are you using?

    Riis
     
  9. If you need more power run that at bridge mode and slap the 2 8s as a 4 ohm load. It makes no difference to the QSCs. Try switching the amps from mods to mains and ofcourse the first thing to do is double check chords. If this system is always plugged in, unplug the chords and get some good cleaner in all the inserts. Sounds to me like the board is in need of a good cleaning. Has it been overhauled at all? Doc
     
  10. uhdinator

    uhdinator

    Apr 20, 2010
    Maine
    Vacuum the front and back vents once in awhile. Do some reading on gain staging your system too.

    Sounds like a clip limit or thermal shut down. built in protection in amps shuts them down if they get too hot and or they are clipping a lot. a speaker cable short can cause it also.
     
  11. Secret Journey

    Secret Journey

    Aug 29, 2009
    Overhauled a board? get ready for a laugh. People do that? Seriously, once you are done laffing, is that something I would send the board out and have done? or would a tech come and do that job here? and stop [email protected]!
     
  12. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Okay, we're done laughing. Some mechanical PM / TLC may be in line but that holds true for any sound reinforcement gear especially that which is repeatedly exposed to "hostile environments" and normal wear & tear. A trip to a reputable shop may be in order...the dentist doesn't come to your house, does he?

    Riis
     
  13. Keithwah

    Keithwah

    Jan 7, 2011
    Milwaukee WI
    Your answer lies in the shoddy ribbon cables used in the Mackie Board. Take it to a reliable Mackie repair center and some $500 later you are on your way. What $500 to repair a $500 mixer? Of course you can it and go find something that makes sense. Provided you are dead positive it's not one of your cables.

    The problem is more inherent in newer Chinese made vlz pro series consoles, but it was a downfall of the product for most of the VLZ and VLZ Pro era mixers. That doesn't mean a lot of people don't get a lot of use and have good luck with their Mackie, they do. Most people get their money out of them. But for servicing, it takes so much time to get down to the top side of the one piece PCB to see if there are any crapped out $5 op amps and to put the thing back together, you are looking at about 8 to 10 hours of labor.

    Do not waste your money on repairing the Mackie. For pete's sake do not replace it with a hunk o' crap Behringer.

    Save your nickels and get yourself a Presonus Live 24.4.2. It's the real deal and the analog feel in a digital package makes it band friendly. Also used analog consoles are really getting cheap. You can find nice used old Soundcraft, Allen Heath and DDA boards that are truly quality consoles for under $1K. But seriously, if you have the means, go get yourself some of that Presonus. I use the 16.4.2 simply because our 5-pc band with 5 vocals fits. But the 24 is a bit cooler, particularly if you have a larger group and want up to 10 dedicated Aux sends with gate,comp,limit, 4-band parametric EQ on each. Work great for in-ear users. Pretty much a set and forget once your ear mix is dialed in.
     
  14. Vinny D

    Vinny D

    Jan 9, 2007
    Warwick, RI
    This would be my guess also....

     
  15. Secret Journey

    Secret Journey

    Aug 29, 2009
    Thanks fellas, for all the advice. That presonus looks likea sweet rig, but there is no way unfortunatly that my church would go to spring 2G's on a new console.
    That said.
    I went there, a little update on the system. Its a mackie 24 channel board, 6 years old, the mains run off a QSC 1450, and the monitors off a samson 1200 watt mixer.
    Attenuaters on both areall the way up.
    I did notice the samson had foam vents where air is sucked in. They were covered in dust. I vacuumed them off, even took them off, and looked inside the amp. Dusty...
    The QSC is on the lowest part of the rack(an inch off the floor) Dusty front an back. I vacuumed it best I could. Also noticed the stage right main cable loose on the QSC. snugged up all cables best I could. Hopefully that would work.
    I dont see sending this out for a repair/maintenece if it is going to cost more than 200$. Would rather just pick up a new analog board. Any more advice would be greatly appreciated. and than k you all again for your time in answering .
     
  16. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Not a good idea. I can clip a 1450 (no attenuation) with my main sliders @ -15 to -10 dB. Before you spend any money on anything, make sure we're not dealing with a setting and / or operator error. From your description, it sounds as if the components are in proper working condition and equipment which is truly broken does not repair itself.

    Knock your attenuators down to 37% (no, this will not limit available ouput power) which is ~10:30 position. This is from a dbx reference and has held true for all 4 of my QSC RMX amps. You may also want to verify the DIP switches located on the rear including the 30/50 hz highpass filters and clip limiters.

    BTW, any way you can access the PA on an "off" day, attach a CD player, and crank some tunes? If the system fails, this is the opportune time to see it first hand and do some addt'l diagnostics.

    Riis
     
  17. Matt Lake

    Matt Lake Supporting Member

    Sep 7, 2010
    Jefferson CITY
    Also, check to see that the speaker hookups are actually making solid connections both inside and out of the speakers . Pinched speaker cords? Bad speaker plugs-male or female? Loose wire somewhere? A bad connection will cause overload and safety shut down. Good Luck with it.
     
  18. TimmyP

    TimmyP

    Nov 4, 2003
    Indianapolis, IN
    I prefer to run the attenuators full up. Keeps maximum headroom in everything ahead of the amp.
     
  19. ggunn

    ggunn

    Aug 30, 2006
    Austin, TX
    That could be the problem, but maybe it isn't. Check all the easy cheap-to-fix stuff before you go off spending a bunch of money on new gear. There is lots of Mackie gear out there older than yours that is still working fine. Behringer, too. Sure, there is better gear out there but not everyone needs it.

    I would go in when the place is empty and try to recreate the problem by patching around recorded music, paying attention to what you are doing when it fails. The time to diagnose a problem is when it is happening. Roofs don't leak when it isn't raining.
     
  20. Growly Lytes

    Growly Lytes

    Dec 4, 2009
    Downunder Oz
    Bass player
    Mates we bassists have a huge task of getting a nice sound.
    Its never straight forward.
    Lots of times we dont even know where to look theres so many things that could be faulty or about to fail.
     
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    Primary TB Assistant

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