Pa System "popping"

Discussion in 'Live Sound [BG]' started by billjr, Jan 5, 2009.

  1. billjr

    billjr

    Jul 25, 2006
    Darlington, SC
    We use a Yorkville MP8dx PA system, and we are now having problems with it having a loud "POP" at times while we play. It only seems to happen when someone sings through the mic. We've tried setting the levels lower, etc, but nothing works. The levels are no where near maxed, and we cannot figure it out. My best guess is that something is loose inside the mixer, as it started the first time we played after moving our equipment to a new practice facility.

    Any ideas?
     
  2. modulusman

    modulusman Inactive

    Jan 18, 2004
    montana
    Have you tried plugging the mic into a different channel, try a different mic and cable?
     
  3. billjr

    billjr

    Jul 25, 2006
    Darlington, SC
    I know we tried different channels, but I'm not sure if it was popping with all the mics or just one. I'll find that out at our next practice.
     
  4. Skywalker83

    Skywalker83 Guest

    Oct 19, 2008
    Tampere, Finland
    Like Modulusman suggests , try a different channel, mic and cable. If its still doing it, follow the chain from the mixer to the amp to the speakers and use a process of elimination.
    I would probably inspect the speakers first though.

    Also, the popping may actually be caused by the vocals. there is something called "popping" that happens when "p" or "b" is said through a mic. If this is the case its just a case of sorting the eq of the vocals and also try fitting a cover to the mic.
     
  5. billjr

    billjr

    Jul 25, 2006
    Darlington, SC
    No, this is not the popping you get from certain consonants. This is a real loud pop, like when you plug a chord into your instrument. It's timing is random, and doesn't seem to corelate with anything specific being sung, just happens rasndomly while the singing is going on.
     
  6. Skywalker83

    Skywalker83 Guest

    Oct 19, 2008
    Tampere, Finland
    is the vocal heard as well as the vocal or does the vocal cut out "pop" then vocal comes back in.

    If the vocal cuts out, you have a bad connection somewhere.
     
  7. bergerXL5

    bergerXL5

    Dec 23, 2008
    Dunmore, PA
    Loose power supply filter capacitor or input capacitor. If it is only happening o one channel, suspect that channel, if it is only left or right, suspect that sub.
     
  8. SpamBot

    SpamBot Guest

    Dec 25, 2008
    St. Paul, MN
    That's a bad cord for sure, I had a bad cord with my bass and what happened was exactly as you described. Try a new cord, that should sort it out. What's happening is that the internal cable is frayed, so the mic is every once in a while unplugging/replugging, in effect, which is why you get that sound.
     
  9. Plugged into a grounded outlet?

    Happens when someone's lips touch a mic?

    Happens when the mixer is bumped?

    Happens when only one mic plugged in?
     
  10. Stu L.

    Stu L.

    Nov 27, 2001
    Corsicana, Texas
    That tells me that it's either the mic, or the mic cord most likely.
     
  11. nsmar4211

    nsmar4211 Guest

    Nov 11, 2007
    We use yorkville speakers through a behringer mixer, the times we've had popping have been from a bad cable or a problem (still haven't found it) with one of the guitar bridges (acoustic, happens when strings hit a certain way). In your case, if it's happening when someone sings through the mic, check and make sure when the people step up to the mic they aren't treading on the mic base or any cables triggering a loose connection.

    See if you can reproduce it to narrow it down, does it happen on only one mic? to only one person? in only one place?
     
  12. Stu L.

    Stu L.

    Nov 27, 2001
    Corsicana, Texas
    You sure it isn't the way the guitar player is hitting the piezo equipped bridge with his palm as he plays? I'd be willing to bet money on that one ;)
     
  13. billjr

    billjr

    Jul 25, 2006
    Darlington, SC
    As soon as we practice again, I'm going to check different mics and chords to see if that solves it. If that is not it, then I'll check the mixer itself for any loose connections or components inside. Thanks for all the help.
     
  14. DWBass

    DWBass The Funkfather

    I would check this as well. Also check the cables. Are the mics pro mics? Shure? AKG? Sennheiser? If the mics are cheap, they can give you issues!
     
  15. nsmar4211

    nsmar4211 Guest

    Nov 11, 2007
    We thought it was, but then it happened while I happened to be watching their hands.....has something to do with the D string hit a certain way (rhythm guitar so all chords). That one has a different pin in it than the others (somehow one of the plastic bridge pins broke so we got a replacement) so that might be why. Not a big deal but will startle you when it does it :)
     
  16. billjr

    billjr

    Jul 25, 2006
    Darlington, SC
    OK, we have a verdict. Our lead guitarist, the PA owner, called a technician and they solved the popping problem. It turns out that the Yorkville PA amp is a 4 ohm amp. The two Peavy speakers are also 4 ohm, which according to the technician, means that the impedence is dropping to 2 ohms when we hook the speakers up from the two output jacks (parallel). The amp was simply being driven beyond it's capacity. To give a quick fix, and at the tech's suggestion, we ran one speaker from the "main" output, and the other from the "monitor" output," since they run on seperate amplifiers. That worked, and we had no popping.

    But this raises a few questions, as we certainly can't use the system like this on stage. We need two main speakers and two or three monitors. Is there a way to fix this without replacing the speakers with two 8 ohm speakers? I'm just not that experienced with these issues, so I will be reading the amp's manual and other resources. Does this problem sound right and make since to anyone?
     
  17. AlembicPlayer

    AlembicPlayer Im not wearing shorts

    Aug 15, 2004
    Pacific Northwet, USA
    that's a very low power system
    you're needing and expecting more then that little practice PA can handle.
    You may need a bigger better system for your needs.
     
  18. billjr

    billjr

    Jul 25, 2006
    Darlington, SC
    It's a Yorkville MP8, which is 400 watts for the main amp, and 200 watts for the monitors. We use it for the vocals (three mics) and acoustic guitar, and I plug my bass in duiring practice, but will not when we play out. Do you still think it's underpowered for just the singers and acoustic? I was a bit off in my previous post, it's rated at 8 ohms, with a 4 ohm min. So I'm thinking we need to replace the main speakers with two 8 ohms.
     
  19. DWBass

    DWBass The Funkfather

    IME, most PA/Monitor cabs I've encountered are 8ohms so they can be used in pairs for a 4ohm load. I think you will have to get 8ohm cabs (or just change out the speakers).
     
  20. Stu L.

    Stu L.

    Nov 27, 2001
    Corsicana, Texas
    Most double woofered cabs (dual 15's, etc) are 4 ohms. If the OP is running a couple of those, that would be the two 4 ohm boxes.

    So, what cabs are being used? You said Peavey, right?