Intermittent Volume Fluctuation

[John Pardue]

I'm having issues again with volumes changing themselves during our worship service. It happened once before and fixed itself after multiple attempts to fix it. It was first noticed during a downloaded video from a PC. It was then noticed with a newer handheld wireless Sennheiser ew 845S as the only active input. We have mostly older equipment.

Yamaha 01V96
Bose Panaray Controller w/ 2 Panaray house speakers and 2 subs
(2) QSC 850s
(1) Peavey 850

My first thought is always amps/controller but secondary thought is output of the 01V96. Input levels don't seem to be fluctuating when this happens. Could it also be power issues at the amp/controller location? Need help.

 

[David Morison]

How big was the change in volume?
If it was about 6dB, you could have an XLR cable with an intermittent connection on one of the signal lines.
If all cabling checks out OK, the other thing I'd check is that there isn't any dynamics processing engaged on the desk with inappropriate settings - maybe a compressor applied on a subgroup you'd forgotten about for example?
HTH,
David.

 

[Rob Timmerman]

I'd exercise any TRS connections (1/4"), as well as the gain pots on the amplifiers. Signal connections often oxidize over time, and exercising the connection will often remove the oxidation.

 

[John Renner]

I had a signal one time that was split to too many pieces of equipment, eq, compressor, tapedecks, etc and the overall effect was that the impedance was too low for the output, it drew too much power from the output jack I was coming off and it had a ramping up just like that. It went from quiet to much to loud and then an immediate drop to nothing. That was on analog gear however. That said, you might check your impedance on the inputs and outputs.