So I had a show Friday night, the standard multi-band, move gear on stage as fast possible, play the set, move gear off stage as fast as possible dance that I've been doing since I was 15 years old. I play in a progressive metal band that uses a fair amount of samples and has keys on a few sections that the drummer handles. For whatever reason, there was a MASSIVE ground hum from those channels during line check. Never had that issue before in our shows, even at the same venue. Worked with FOH to swap channels, try different cabling..... nothing. No samples or keys to monitors or mains without massive hum, so we split the difference and FOH took them as loud as possible without the hum overpowering everything else. So we fought through it, and then halfway through the 40 minute set, the keys/samples cut out completely, and there was just a steady, present hum. I'm not entirely sure what happened, and we'll check the drummers gear at our next rehearsal to see if something odd was going on that we can replicate and resolve, but that was not a fun gig.
How did you send the samples to the FOH? DI boxes? Were they battery powered or phantom powered? Was the ground switch engaged on the box? Just some things to maybe check... BnB
Passive DI (relatively certain). They tried engaging and disengaging the ground switch with no change. We're gonna try and come up with a backup solution for next time.
Might have had the system powered on 2 or more separate circuits that didn't have a good common ground between them? Difference in ground potential between 2 different circuits will hum every time.
As an electrician I've found alotta bars have crappy wiring, gotta deal with a power conditioner to be true.