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Topic: ATTN: Soundguys-Feedback Problem - PA or Steel Rig? |
Tony Rankin
From:
Land O’ Lakes, FL
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Posted 13 Aug 2017 1:42 pm |
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This morning while playing at church I experienced a very unusual feedback issue. I was playing my steel into a Telonics VP, then into a Revelation Tube Preamp with a Lexicon MPX1 for effects(Reverb and Delay). That was sent to two TC Furlong CB12's. I send the PA board two signals. One channel direct from the XLR out of the Revelation and the other a Sennheiser E906 draped over the cabinet of one (left channel) CB12.
I had played on four tunes in the set, with no issues. A cordless microphone was being passed through a group of people and at the conclusion of their "self introductions" a feedback noise was generated. (Typical of what you might hear when a microphone gets too close to a stage monitor.)
The noise level went quickly, (about two seconds) from the loud feedback to a much lower volume feedback with a slightly different frequency that was continuous and unchanging. The soundman announced it was coming from the steel and he had everything else "shutoff". I quickly killed the preamp by switching it off. The sound continued and I turned around and could hear the sound coming only from my left channel speaker (the one that was mic'ed) but not the right "un-mic'ed" speaker. I shut the AC power off and it went silent.
I then turned the power back on and turned on my preamp. All was normal except for my signal in the monitors, which was now much lower in volume.
Any ideas what happened here? I looked like the bad guy in this, but I don't have a clue how I, or my equipment, could have started this issue. The volume pedal was back and my right hand was muting the strings. Is it possible for something to have happened that caused that one speaker and/or microphone to begin a feedback situation?
I'm baffled!
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Tony Rankin |
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Eric Philippsen
From:
Central Indiana, USA
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Posted 13 Aug 2017 2:53 pm
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I hate it when those type of situations occur.
I can't say for sure what happened but I'm pretty sure a contributing factor was a feature of the Rev preamp. That is, putting it in standby mode does not immediately cut the unit's signal to zero. It can actually take up to 30 seconds for it to reach that zero-signal level. That means when you shut the Rev down it was still processing signal.....and producing some form of feedback.
You also mention powering everything up again after the incident. All was ok except your monitor level was less. Only a guess, but perhaps the soundman cut your monitor level at the board. |
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James Phillips
From:
Michigan, USA
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Posted 13 Aug 2017 4:22 pm
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The sound guy prolly had your steel too loud in your monitor...
The feed back was from the mic on your amp,feeding back into the monitor...
That's something you don't really have any control over, and a competent sound guy would just fix it in realtime, instead of panicking and turning everything off.
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Visit my Studio: LimeStoneLabs at.. http://Facebook.com/LSlabs
"Let the Bridges We Burn Light the Way" |
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Tony Rankin
From:
Land O’ Lakes, FL
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Posted 14 Aug 2017 5:47 pm
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Eric -- I know about the delay in shutting off on the Rev. In this scenario enough time passed that I heard it cease sending signal.
James -- That to me is the most logical explanation. The only thing that I can't figure out is how my TC Furlong powered speaker cabinet continued the sound after the PA system went off. The sound was definitely coming from that cabinet and that one alone. Is it possible for my speaker cabinet to somehow sync with or pickup the feedback from the PA monitors?
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Tony Rankin |
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Godfrey Arthur
From:
3rd Rock
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Posted 15 Aug 2017 1:18 pm Re: ATTN: Soundguys-Feedback Problem - PA or Steel Rig?
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| Tony Rankin wrote: |
| could hear the sound coming only from my left channel speaker (the one that was mic'ed) but not the right "un-mic'ed" speaker. |
If you heard the feedback tone coming from just your one amp's speaker then it's not the PA that is feeding back and if the soundman shut all his end off that is extra proof that it was either your amp or the fact you had two similar powered speakers connected to the preamp?
The Senn E906, was this from the soundman's gear hooked up to his board? Or was it tapped off through your preamp?
With your described gear knowing how you had it hooked up in from where and out to where AND WHAT TYPES OF CONNECTORS you used throughout and were you mixing balanced inputs/outputs with unbalanced ins/outs and mixing unbalanced mono connectors into/out of balanced (TRS three wire) jacks?
Your Lexicon has both balanced and unbalanced conections.
Amps like the VOX ADVT solid state/tube hybrid guitar amp series were known to squeal a loud feedback tone from just plugging in a guitar cable into the input on the amp so note that there are situations when the amp has an oscillation problem.
In your case you have several systems tied together and maybe a loop was created to make the feedback oscillation.
But if you want to trace this, would need to know how you hooked it up exactly AND to the PA, what cables/jacks you used AND if this is the first time this has happened and if you did anything different in hooking things up this episode.
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ShoBud The Pro 1
YES it's my REAL NAME!
Ezekiel 33:7 |
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Tony Rankin
From:
Land O’ Lakes, FL
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Posted 15 Aug 2017 6:21 pm
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First time it happened in years of use and in many venues. I have used this system weekly for over two years where this occurred. 1/4 instrument cables from the Revelation preamp to each of the Furlong CB12 speaker cabs. XLR cables to the mic on one cabinet and XLR to the XLR output of the Revelation both from the PA. The MPX1 is hooked into the fx loop of the Rev using 1/4" cables.
The first feedback was loud and in my opinion was in the PA whether or not it came from my mic. But the second and quieter sound that was from the mic'ed cabinet baffles me.
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Tony Rankin |
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Godfrey Arthur
From:
3rd Rock
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Posted 15 Aug 2017 7:14 pm
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You mentioned there was also feedback coming from your cabinet. The mic wasn't running through your pre was it?
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ShoBud The Pro 1
YES it's my REAL NAME!
Ezekiel 33:7 |
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mtulbert
From:
Plano, Texas 75023
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Posted 16 Aug 2017 3:26 am
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This sounds totally off the wall ( no pun intended) but my band experienced the same thing several years ago at a gig in the Stockyards at Ft. Worth. We had used the same setup for years with no issues and then all of a sudden we got a feedback problem that was so bad that a couple of speakers were blown and a power amp was damaged as well. The culprit? A wireless microphone that the opening entertainers (who were staging a gun fight) were using. And the reason that this was the culprit was because the wireless system was very old and on frequencies that are not allowed any more because they were allotted by the FCC for other commercial uses.
It sounds really far fetched, but both the band manager and I heard from different people that this can definitely reek havoc because the microphones and receivers are picking up other signals on those frequencies.
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Mark T
Rittenberry Laquer D10, Rittenberry Prestige SD10, Revelation Preamp,Revelation Octal Preamp,Lexicon PCM 92 Reverb, Furlong Cabinet |
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Tony Rankin
From:
Land O’ Lakes, FL
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Posted 17 Aug 2017 8:22 am
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Godfrey...No it wasn't. The mic was plugged straight into the church sound system with a microphone (XLR) cable.
Mark...I know they use a combo of new and old wireless mic. How old, or what frequencies, I don't know.
Something happened that caused my TC Furlong CB12 powered speaker cabinet to have a reaction. I think to play it safe on my end, I'll just go direct from now on. I don't think the tone is the same but I don't want 600 people thinking I'm the culprit that's wrecking the sound.
By the way, this happened while the pastor was praying! 
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Tony Rankin |
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Tony Rankin
From:
Land O’ Lakes, FL
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Posted 20 Aug 2017 4:35 pm
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I have the answer. The sound guys told me this morning that they had erroneously patched every instrument and every mic into my left (the mic'ed) channel. Wow!!
Definitely not my gear that caused it!
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Tony Rankin |
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Godfrey Arthur
From:
3rd Rock
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Posted 21 Aug 2017 7:40 pm
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| Tony Rankin wrote: |
I have the answer. The sound guys told me this morning that they had erroneously patched every instrument and every mic into my left (the mic'ed) channel. Wow!!
Definitely not my gear that caused it! |
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ShoBud The Pro 1
YES it's my REAL NAME!
Ezekiel 33:7 |
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