handyandi Posted March 30, 2009 Share Posted March 30, 2009 Had this happen to me a few weeks ago in a school. Turning the Hand Held senny I had on to find loud feedback with my PA muted. Culprit was the installed school rig which just gets left on! No one uses off switches in schools. At least you will know for next time! Very early in my career one person I had commenting on the lack of vocal level in the 1st song in a highly reverberant church with a 30+ choir & rock band turned out to be David Grant, good job I was polite to him & always am as courteous as possible. Its a hard job sometimes but that's why we love it! Andi Link to comment Share on other sites More sharing options...
will_i_am Posted March 30, 2009 Share Posted March 30, 2009 Ok guys - I'm fairly new to this so go easy on me <_< Just done a gig at the local school hall, which I've done a few times before. the acoustics are pretty nasty with lots of refelctions from the end wall. however this time I took longer with my setup and had a few more bells and whilstles. I've got equalisers for the monitor and house mixs and spent an hour with the A&H acoustic analyser software removing the feedback frequencies. however even at this stage I noticed really early onset of feedback, particularly on the house side, which the frequency notching helped - but did not stop. The speakers were positioned about 5 foot in front of the lines of the mics, angled slightly (~15 degrees) into the centre. mics were 3 off SM58, 1 off sennheiser 865, the SM58's seemed to be worse culprits. drums were miced (kick,snare & overhaeds) plus 2 SM57 on guiotar amps (Bass DI). main speakers beyma CP600 on top of PDN15 driven by chevin amps. monitors are pair of 150W anyhow had a miserable evening trying to control the feedback - one father (professional sound engineer) gave me a right bollicking - I asked him for some contructive advice - but he said sort it at sound check. 7 bands to do in 3 hours and they always arrive on stage with no leads, not tuned etc & why wasn't he doing the gig (always unpaid)? ended up virtually with nothing on the monitors to try to control it - but was still bad. one thing I did notice was that as soon as they stopped playing the feedback got much worse - but I guess this is the compressor releasing? anyway - feels better to have got that lot off me chest - but anyone got any suggestions as to why this was?brand new to this forum so I have no idea if this post will turn up in the right place.!! what compression ratios where you using on the offending mics? how close were they to the intended source? to much compression is a possible culprit, and possibly not having the mics close enough to the source and therefore having gains to high might not help a situation.. will A concurrent post has been automatically merged from this point on. Ok guys - I'm fairly new to this so go easy on me Just done a gig at the local school hall, which I've done a few times before. the acoustics are pretty nasty with lots of refelctions from the end wall. however this time I took longer with my setup and had a few more bells and whilstles. I've got equalisers for the monitor and house mixs and spent an hour with the A&H acoustic analyser software removing the feedback frequencies. however even at this stage I noticed really early onset of feedback, particularly on the house side, which the frequency notching helped - but did not stop. The speakers were positioned about 5 foot in front of the lines of the mics, angled slightly (~15 degrees) into the centre. mics were 3 off SM58, 1 off sennheiser 865, the SM58's seemed to be worse culprits. drums were miced (kick,snare & overhaeds) plus 2 SM57 on guiotar amps (Bass DI). main speakers beyma CP600 on top of PDN15 driven by chevin amps. monitors are pair of 150W anyhow had a miserable evening trying to control the feedback - one father (professional sound engineer) gave me a right bollicking - I asked him for some contructive advice - but he said sort it at sound check. 7 bands to do in 3 hours and they always arrive on stage with no leads, not tuned etc & why wasn't he doing the gig (always unpaid)? ended up virtually with nothing on the monitors to try to control it - but was still bad. one thing I did notice was that as soon as they stopped playing the feedback got much worse - but I guess this is the compressor releasing? anyway - feels better to have got that lot off me chest - but anyone got any suggestions as to why this was?brand new to this forum so I have no idea if this post will turn up in the right place.!! what compression ratios where you using on the offending mics? how close were they to the intended source? to much compression is a possible culprit, and possibly not having the mics close enough to the source and therefore having gains to high might not help a situation.. will Link to comment Share on other sites More sharing options...
oligoon Posted March 31, 2009 Author Share Posted March 31, 2009 the PDN15 are mounted in vented 150 litre cabinets designed using WinISD to have a response down to 50Hz and will inevitably spill quite a bit from the back of the cabinets. I would go for horn mounted drivers - the ones on the speakerplans website look good - but the size and weight preclude it. the beyma CP600 obviously have a horn so won't spill much from the back. X over was set at 1200Hz. I certainly don't want to go through that again. Link to comment Share on other sites More sharing options...
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