Noise on Audio System

Hello, I’m the a/v guy on this project. Figured I’d chime in with a few details on our setup:

-Our guitars go through amp modelers, straight into the system via DI boxes (no physical amps)

-All stage power runs through an isolation transformer.

-Feed to lights does NOT run through I isolation transformer. Power goes straight to dimmer.

-we’ve bypassed any and all effects pedals (guitar straight to DI with no power in the signal chain) and the noise is still present, albeit lower since there are no pedals boosting the gain)

- all of our stage lighting fixtures are elation (so they have higher quality transformers)
 
Still depends on if the modeler (which i think you mean profiler) has its own amp, and whether you are inadvertantly amplifying the signal twice...
And exactly which output you are using (and if its high/low impedence)
and if the omh is correct.
If the profiler has its own amp, any chance it was powered up without a load?
That would be no bueno, exactly why i do not like using a di settup... time to check the amp first independent of the house system. Find a speaker with correct ohm and power rating and check it.

Also make sure guitar doesnt have active electronics. You can also just plug a guitar straight to the mixer to see if problem goes away, you just need to find a tr 1/4" input...

And of course, make darn sure the settings on the amp are correct...
 
hbiss said:
Ok. But what happens if you do have a guitar amp on stage with a guitar connected to it? Do you hear hum from it?

-Hal
Click to expand...
I think it would be better but places like this want control over everything on stage... but pedals should not be a issue anyway.
I think a amp/speaker combo miked in a iso/airline case would work best... my guess is the modeler got cooked...
 
brianbuffon said:
Hello, I’m the a/v guy on this project. Figured I’d chime in with a few details on our setup:

-Our guitars go through amp modelers, straight into the system via DI boxes (no physical amps)

-All stage power runs through an isolation transformer.

-Feed to lights does NOT run through I isolation transformer. Power goes straight to dimmer.

-we’ve bypassed any and all effects pedals (guitar straight to DI with no power in the signal chain) and the noise is still present, albeit lower since there are no pedals boosting the gain)

- all of our stage lighting fixtures are elation (so they have higher quality transformers)
Click to expand...
Do the DI boxes have a ground lift on them? If so, you might try that to see if the hum is coming from the ground. Don't leave them that way, just use as a test.
 
rambojoe said:
think it would be better but places like this want control over everything on stage... but pedals should not be a issue anyway.
I think a amp/speaker combo miked in a iso/airline case would work best... my guess is the modeler got cooked...
Click to expand...
No, only as an experiment to isolate the guitar from the system. If it's the actual guitar pickups picking up the hum, I would expect to hear the same hum from the stand-alone guitar amp speaker.

-Hal
 
hbiss said:
No, only as an experiment to isolate the guitar from the system. If it's the actual guitar pickups picking up the hum, I would expect to hear the same hum from the stand-alone guitar amp speaker.

-Hal
Click to expand...
Its not the pickups... humbuckers should be quiter- ergo hum.. buckers...
You do realize we were saying the same thing about the amps. So quick with the no :) which is why said plug into zee board.
Im married... i laugh at your no's!
J.k...
 
hbiss said:
Ok. But what happens if you do have a guitar amp on stage with a guitar connected to it? Do you hear hum from it?

-Hal
Click to expand...

Yes. In fact one one of the earlier tests that I did involved taking an amp throughout our sanctuary space to see if the results varied. As long as the lights were on there was a buzz, when the lights were off, it went away.
 
Little Bill said:
Do the DI boxes have a ground lift on them? If so, you might try that to see if the hum is coming from the ground. Don't leave them that way, just use as a test.
Click to expand...
unfortunately, we’ve tried almost every DI under the sun, with no results. The evidence definitely points towards radiated EMI from the lights, especially with the 90 degree turn phenomenon
 
rambojoe said:
Still depends on if the modeler (which i think you mean profiler) has its own amp, and whether you are inadvertantly amplifying the signal twice...
And exactly which output you are using (and if its high/low impedence)
and if the omh is correct.
If the profiler has its own amp, any chance it was powered up without a load?
That would be no bueno, exactly why i do not like using a di settup... time to check the amp first independent of the house system. Find a speaker with correct ohm and power rating and check it.

Also make sure guitar doesnt have active electronics. You can also just plug a guitar straight to the mixer to see if problem goes away, you just need to find a tr 1/4" input...

And of course, make darn sure the settings on the amp are correct...
Click to expand...
The “amps” in question are Line6 Helix/HX Stomp and a strymon Iriduim Modeler. Also, it should be mentioned that we used the same exact gear at our old space and did not have any issues
 
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