Phase Cancellation in IEM's

[fenderbenderlax]

Hi Folks,

I was at a gig yesterday and had an issue with my IEM set up. There seemed to be some phase cancellation going on with my guitar signal. Basically the guitar signal seemed to follow a sine wave pattern at many points during the gig (close to 75% of the gig). I'm using the Audio Technica ATW 3255 transmitter/receiver coupled with the Sensaphonics 3DME system. My limiter was turned off and I was just taking the direct FOH mix from the engineer for the IEM feed. any experience with this issue and how to resolve it?? The Front of house mix was perfect. We recorded the show and it did not seem to have any issues at all. Many thanks in advance!!!!

 

[Joshua_L]

Does your in ears system was set to stereo?

 

[chris]

Was your mixer buss send panned hard left and right? Sounds like it wasn’t.

 

[fenderbenderlax]

Does your in ears system was set to stereo?

Yes the IEM was set to stereo

 

[fenderbenderlax]

Was your mixer buss send panned hard left and right? Sounds like it wasn’t.

I talked to our engineer and he said that it was panned. The mix was basically everything other my guitars in mono and my guitar channels were set to stereo and panned.

 

[chris]

eh, something caused it. some mixers don't auto pan the Bus/Aux sends even if you pan the Mains.

 

[fenderbenderlax]

eh, something caused it. some mixers don't auto pan the Bus/Aux sends even if you pan the Mains.

ah let me ask my engineer that. We use the Behringer X32 system. Will look into that.

 

[chris]

ah let me ask my engineer that. We use the Behringer X32 system. Will look into that.

yeah x32 you have to specifically pan each channel for the Buses if they are stereo. i believe this is NOT available in the iPad app. it's only on hardware or the PC editor.

 

[fenderbenderlax]

yeah x32 you have to specifically pan each channel for the Buses if they are stereo. i believe this is NOT available in the iPad app. it's only on hardware or the PC editor.

I see..I will ask our engineer...I'm thinking maybe its best to go mono to FOH anyway...maybe that will resolve the issue

 

[fenderbenderlax]

yeah x32 you have to specifically pan each channel for the Buses if they are stereo. i believe this is NOT available in the iPad app. it's only on hardware or the PC editor.

our engineer checked the template again that he uses for our band and found that indeed he did not pan the bus sends. Thank you very much for that tip.

 

[toneseeker911]

If there was phase cancellation when summing , then your audience also heard it. This is what I am usually afraid of with stereo to FOH.

 

[chris]

If there was phase cancellation when summing , then your audience also heard it. This is what I am usually afraid of with stereo to FOH.

FOH was stereo - the pan controls for Main are featured and seperate from Stereo Bus pans. the issue was in the Bus/Monitor sends, not Mains.

 

[toneseeker911]

FOH was stereo - the pan controls for Main are featured and seperate from Stereo Bus pans. the issue was in the Bus/Monitor sends, not Mains.

Yes, I get that just the IEM bus was not panned. But , the mains , a lot of times are run as mono, which means the stereo guitar signal would have been summed. Even if the PA was run as stereo, anyone not dead center would have heard some version of phasing , since summing the original signal was not clean as evidenced by the wrongly configured IEM bus.
I've heard room audio recordings when I give a stereo signal to FOH and end up liking mono better. I'm maybe not doing something right.

 

[chris]

to me, light stereo effects (not crucial to the main tone of the song) work for everyone in the room. yes everyone may have a different resulting mix, but it still sounds more interesting than straight mono in sections of songs, as you perceive slight time differences or other stereo fun which expands on the basic tone.

did a gig sunday where i did mono the first set to test their PA system, and then went to my usual stereo for the 2nd set. sounded way better, more 3D and people definitely enjoyed the sound more (i asked and they said it sounded more 3d and interesting).

of course it depends exactly what you're trying to accomplish, but people not getting the same exact mix every millimeter of the room is not a good reason for me. even mono people won't get the same mix so at that point i'd rather it sound more interesting.