Weird Grounding Issue with a Vocal Mic

[GreatOz]

Good day,

I'm somehow having a grounding problem with my vocal microphone. Anytime I'm not touching a metal part of either guitar, I get feedback on the vocal microphone in front me. I use two guitars live with an A/B switch to go between them, and I can touch either guitar's metal bridge, strings, anything metal, etc, and the feedback disappears.

There is another microphone on the guitar cabinet and we aviom for in-ear monitors.

Any suggestions for things to check?

Thanks,

[beaubrummels]

The description sounds like it's just buzz picked up by the cab mic. How do you know it's coming from the vocal mic?

[GreatOz]

The aviom has individual channels for all the instruments, my vocal microphone included. If I have the sound man mute my microphone or turn it all the way down in the aviom, the feedback goes away.

It's definitely my vocal microphone.

[hamerfan]

Use the elimination method and change/ leave out one piece at a moment. Start with the A/B Pedal.

[beaubrummels]

The aviom has individual channels for all the instruments, my vocal microphone included. If I have the sound man mute my microphone or turn it all the way down in the aviom, the feedback goes away.

It's definitely my vocal microphone.

"Feedback" is a howling through the cab speaker when the pickups function like a microphone in a loop with the speaker and would only stop if you grab the strings or touch the pickup; I'm assuming you are dealing with a 60hz buzz associated with power or line interference. I would look into what devices are sharing power sources, and in particular any lights that are on the same circuit as the audio devices. If you have stages lights with cooling fans in them, those can get picked up by your pickups, even if on a separate circuit. If flourescent lights are on the same circuit as your amp power, those can get picked up by your guitar and amp. But the fact that it's coming through the vocal mic makes me think the buzz is there all the time and you're only hearing it in between playing when your mic picks it up. There also might be compression on your vocal channel that effectively turns the buzz up louder when you're not singing.

If it's literally acoustic feedback from your microphone to your in-ears, then your vocal mic is likely picking up your in-ears and feeding back that way and the guitar is a red herring. You would have to turn down or re-EQ your in-ears. Are your in-ears isolating? How many db of isolation? Or do you play with one in-ear out? That can get picked up on mics also.

[GreatOz]

Thanks for the tips, turns out it was a faulty microphone. My setup is fine.