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<blockquote data-quote="Daniel Postilnik" data-source="post: 5697" data-attributes="member: 184">Hi folks, I thought I would share an experience I had with a certain acoustical phenomenon that a number of JV people might not have had a chance to encounter.I was working on a large show that required 20 wireless handheld microphones (Shure UHF-R series, SM58 capsules) to be open at all times due to the nature of the show. The monitor engineer was working on getting all 11 mixes on stage&nbsp; EQ&#039;d and stable for use by all of these microphones. While the microphones were being held backstage behind a curtain, he had some trouble getting rid of a low-level consistent &quot;oooooooo&quot; in a number of the wedges that sounded like the edge of low-mid frequency feedback even though no mic was near them. I was thinking &quot;Wow, our GBF has really suffered from having this many open mics.&quot;After a good amount of hacking at graphics with no results, he decided to take a peek backstage, where he discovered the problem. The microphones had all been lined up capsule-to-capsule, which apparently creates one very large, high sensitivity microphone.I don&#039;t know the technical term for this phenomenon, but when the mics where flipped so they alternated capsule/butt, the low-level wailing in the monitors went away. The Varsity-level technicians who were handling the microphones didn&#039;t know not to do this (granted, this was a third-world Caribbean country), so I thought some of you on this forum might benefit from knowing about it.Cheers!</blockquote>

[QUOTE="Daniel Postilnik, post: 5697, member: 184"] Hi folks, I thought I would share an experience I had with a certain acoustical phenomenon that a number of JV people might not have had a chance to encounter. I was working on a large show that required 20 wireless handheld microphones (Shure UHF-R series, SM58 capsules) to be open at all times due to the nature of the show. The monitor engineer was working on getting all 11 mixes on stage EQ'd and stable for use by all of these microphones. While the microphones were being held backstage behind a curtain, he had some trouble getting rid of a low-level consistent "oooooooo" in a number of the wedges that sounded like the edge of low-mid frequency feedback even though no mic was near them. I was thinking "Wow, our GBF has really suffered from having this many open mics." After a good amount of hacking at graphics with no results, he decided to take a peek backstage, where he discovered the problem. The microphones had all been lined up capsule-to-capsule, which apparently creates one very large, high sensitivity microphone. I don't know the technical term for this phenomenon, but when the mics where flipped so they alternated capsule/butt, the low-level wailing in the monitors went away. The Varsity-level technicians who were handling the microphones didn't know not to do this (granted, this was a third-world Caribbean country), so I thought some of you on this forum might benefit from knowing about it. Cheers! [/QUOTE]

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