sound engineer & phase cancellation

S

s6275

Member
I'm posting this hoping someone will be able to point out something I missed.

Last Summer, I was playing at a festival in a group with a guitar player who also had an FM3. We were standing between my pair of JBL EON 612 speakers (on the floor). The L & R of my FM3 was routed to the Input 1 of each speaker, and his L & R to the Input 2 of each speaker. We didn't encounter any issues with phase cancellation at any of the pre-show rehearsals.

At the festival, the sound engineer wanted to use the THRU jacks on the speakers to connect us to the PA. I told him I thought that would work, but that he would probably need to hard pan two channel strips hard L and hard R.

The show started, and we sounded great on stage...but everyone in the crowd from 10 ft back was all making this face:

":confused:"

The people right up by the stage were mostly hearing the group through our monitors and thought it sounded great.

My theory: People 10 ft.+ back reported not being able to hear the guitars, so they were hearing the group...minus the almost completely phase-cancelled guitars...which was probably weird in their defense.

Am I on the right track...or am I missing something else at some other point in the chain that I can correct?
 
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My theory: the sound tech made a mistake when connecting or configuring the channels. Get together with the other guitarist sometime, and just try to phase-cancel each other out. I don’t think you can do it.
 
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I can only imagine that the soundtechnican put both channels in the stereo middle and has also one channel phase reversed, so the crowd only heard the difference in the stereo signal which will be a lot of the wet signal (reverb, delay, chorus…) but no dry signal.
I also wondered why you let him connect to the mixed output of each speaker, so also if he did a hard panning and no phase reversed channel, he would’nt be able to do a well balanced mix of the both guitars because they are pre mixed in each speaker which makes no sense for the FOH system. Next time make it easy and give him the second out of your FM3!
 
Petrocelli said:
I can only imagine that the soundtechnican put both channels in the stereo middle and has also one channel phase reversed, so the crowd only heard the difference in the stereo signal which will be a lot of the wet signal (reverb, delay, chorus…) but no dry signal.
I also wondered why you let him connect to the mixed output of each speaker, so also if he did a hard panning and no phase reversed channel, he would’nt be able to do a well balanced mix of the both guitars because they are pre mixed in each speaker which makes no sense for the FOH system. Next time make it easy and give him the second out of your FM3!
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It was offered. He “highly preferred” using the speaker thru.
 
Regardless of the cause of the issue, it was merely a symptom of the sound engineer not knowing what the hell he was doing. Lotta red flags here. Hopefully, you don't interface with him on a regular basis.
 
Rex said:
My theory: the sound tech made a mistake when connecting or configuring the channels. Get together with the other guitarist sometime, and just try to phase-cancel each other out. I don’t think you can do it.
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Using the word "stereo" resulted in a textbook "deer in headlights" reaction.
 
Rex said:
Depends on what you’re going for.
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Just the best practice. The simplest example: normal preset with stereo delay and reverb. Should I ask the sound guy to hard pan channels in this situation?
I'm playing with it at home and I'm not sure I hear the difference between hard panned and "all at 0" panning setting.
 
Chromatizm said:
Just the best practice. The simplest example: normal preset with stereo delay and reverb. Should I ask the sound guy to hard pan channels in this situation?
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Rex said:
Depends on the venue and what you’re trying to accomplish. Sometimes panning each channel by 30-50% works best, so there’s some signal going to both sides. Sometimes 100%. If you’re just trying to place each instrument in a stereo field, you’ll want to send just a single channel, and let the house pan you where they want you. Some PAs or rooms just don’t support stereo.
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Chromatizm said:
I'm playing with it at home and I'm not sure I hear the difference between hard panned and "all at 0" panning setting.
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If you don’t hear a difference between panned and not panned, then your signal is being collapsed to mono somewhere in the chain.
 
Is FOH stereo?

If it is, and your preset is, panning full wide will keep it the way you had it.
Less width than that collapses it some, down to the extreme of panning both sides to center, which makes FOH mono.

However, it's not 100% clear that stereo is great live. Only people right on the center line hear full stereo, everyone else gets more of the side they're closer to, possibly not hearing the other side at all.
 
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