Most Bizarre Live Sound Issue EVER. In Need Of Help!

Discussion in 'Live Sound [BG]' started by dabigc5, Nov 2, 2017.

  1. dabigc5


    Jan 23, 2010
    Chicago Suburbs
    The Problem: Signal (or ground?) Noise/Buzz/Hum

    Original Signal Chain: G&L L2000 -> Boss TU-3 Tuner -> Markbass Mini Boost -> HBE Hematoma -> TC Electronics Spark Booster -> EHX Big Muff -> EHX Pulsar Tremolo -> IMP DI (all powered with Hardwire V10 Isolated Power Supply) (using short patch cables - can't remember the brand, but let's assume they are mid-grade cables)

    With this set-up, I had some VERY bad buzzing, but only at church - not when I plug into my amp at home. When touching the knobs/switches on my bass, the noise almost completely goes away. When touching the control cavity cover on the back (even with my leg, through my jeans) the buzzing gets far worse. Originally I assumed this was some sort of ground loop so...

    Step 1: Flip Ground/Lift switch on DI. This had little to no effect.
    Step 2: Bypass effects pedals, going straight into the DI. Again, little to no change. I even tried disconnecting the power supply, and still nothing.
    Step 3: Change battery/play in passive. Playing passive helped - but there was definitely still some funky buzz going on.
    Step 4: Try another bass. I went with a passive and an active - both had the same results as the G&L.
    Step 5: Remove control cavity cover. A couple of times this nearly eliminated the problem.


    Step 6: Have someone else hold/play the bass.

    Believe it or not, that fixed it. Completely. Intrigued, I tried figuring out what was different about me that was causing this issue. This leads us to...

    Step 7: Stop using on stage Aviom (in ear monitor). This, also fixed the issue. I had my friend try using the Aviom and playing the bass, and the buzz came back.
    Step 8: Use wireless IEM (Sennheiser, off stage). Again, this fixed the problem.
    Step 9: Plug my power supply into another outlet. This fixed the issue, but there is a disclaimer - I had to be plugged into an outlet 50 feet from the stage, in the congregation. When bypassing the pedals, this did not help at all - it only helped when using the pedals.

    So... it seems to me that we have way too much plugged into one circuit, and somehow, being connected to a wired Aviom (who's power is also plugged in on stage) is causing a massive buzzing sound. Here come my questions.

    1. Have any of you ever experienced something like this?
    2. Is my touching the controls a way of "regrounding" the bass, if you will? Why does this cause the buzz to go away?
    3. Why is this only happening to me? It doesn't happen to our acoustic guitarist, keyboardist, or electric guitarist.
    4. What is the actual problem? We have a lot plugged into a bunch of different outlets, all on stage. No one knows how many circuits, or what size circuits we have on stage.
    5. How would you fix this? Buy any gear? Pedal/power conditioner/wireless rig/etc? Do we need to bring out an electrician or something?

    Thanks in advance everybody!!
    Dec1975 likes this.
  2. Stumbo

    Stumbo Guest

    Feb 11, 2008
    Electrician to trace circuits and breakers, test outlets and diagram wiring.
    Dec1975 likes this.
  3. s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    1964 Audio artist, Fractal Audio Beta Tester
    Can you say "ground loop" ???
    These can be a PITA to resolve...
  4. Flippy


    Jun 9, 2017
    Sounds like the church outlets are not grounded. as @s0c9 suggests, this may be also a ground loop. Are you connected to different outlets? Power strips don't count unless they're connected to different outlets as well.
  5. dabigc5


    Jan 23, 2010
    Chicago Suburbs
    Thanks for the replies.

    At one point, I had thought it was a ground loop, but it confused me that the culprit seemed to be the Aviom. Thank you for clarifying!

    And I'm plugged into an outlet all by myself, no powerstrip involved. And like I mentioned - the problem even occurs when I'm bypassing my pedals completely, and the DI is passive.

    Any thoughts on why the ground switch doesn't eliminate my problem? My apologies if that's a dumb question.
  6. thekyle55


    Mar 14, 2012
    When there is no ground, a ground lift will do nothing. Ground lifts help when you are plugged minto different circuits, and there is a different potentials on the grounds of the circuits.
  7. Dec1975


    Aug 30, 2006
    Cedar Park, TX
    I wish I had some advice to offer, but I don't. I have the exact same issue at my church, and pretty much the same set up. I was going to try using an old powered wedge instead of the Aviom this week.
  8. Deltatim


    Nov 5, 2016
    Stockton, CA
    Pick up an outlet tester plug. Plug it in, and the LEDs show if the hot-neutral, and ground are proper. Older buildings may not have grounded wireing, even tho the outlets may have been changed to 3 prong. An accident waiting to happen.
    aborgman likes this.
  9. walterw

    walterw Supportive Fender Commercial User

    Feb 20, 2009
    what about when touching the strings?

    that should do the same thing; if not then you have a lost bridge ground in the bass itself.
  10. dabigc5


    Jan 23, 2010
    Chicago Suburbs
    Thank you - that makes a lot of sense!

    So sorry to hear I'm not the only one... I'll let you know what I discover.

    Will do - thank you!

    It is not doing the same thing. That's what I had thought too... it's possible that this is the case with all of my basses, but I find that a bit hard to believe - and I'm having this issue with all of them...
  11. walterw

    walterw Supportive Fender Commercial User

    Feb 20, 2009
    touching the strings should be the exact same as touching the knobs or whatever. if not then there's a problem with the bass.

    are you using tapewound strings?

  12. My prediction -

    You've got an outlet (either the one your bass is plugged into, the one the console fed by the DI is plugged into, or the one the Aviom is plugged into) that has a bad safety ground.

    Check all the outlets with an outlet tester. It could be the outlet at the wall, or the outlet on a power strip.
  13. dabigc5


    Jan 23, 2010
    Chicago Suburbs
    Hey guys - quick update.

    We’re having someone come and check out the electrical system later this month, but I’ve found a solution that works for me. I picked up the Line 6 G70 Wireless System, and that killed the ground loop. So far I’m happy with it, as it has replaced my tuner, my ABY, and has a gain adjustment with saveable presets, so changing basses during the set is much easier for my sound engineer.

    Thank you all for the input - hopefully we can get the wiring and circuits in that building figured out so no one else deals with the same issue.
  14. dabigc5


    Jan 23, 2010
    Chicago Suburbs
    Rounds and flats.