pineweasel Posted April 16 Share Posted April 16 I saw a band recently in a smallish pub, and I was intrigued by the positioning of their PA speakers. A 4-piece, they had the drums and keys next to each other along a wall, with bass and guitar in front. All instruments plus the kick were going through the PA (no amps), and all four players had a vocal mic. The PA mains (15” Yamahas) were either side of the drums and keys, next to the wall and hence well behind the front mics. No sub as far as I could tell. The guitarist and bassist both had wedge monitors. They sounded pretty good and the volume was decent for the room, which was full with a raucous crowd. I can see the appeal of getting the PA mains out of the way, but how do you get an arrangement like that to work without feedback? Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted April 16 Share Posted April 16 I saw a band do this last year so I asked them. The answer was that the set the speakers up and then turned up to a volume where feedback was just not occurring, Then adjust the other instruments to the vocals. 1 Quote Link to comment Share on other sites More sharing options...
pineweasel Posted April 17 Author Share Posted April 17 14 hours ago, Chienmortbb said: I saw a band do this last year so I asked them. The answer was that the set the speakers up and then turned up to a volume where feedback was just not occurring, Then adjust the other instruments to the vocals. I see, so workable for modest volumes. It probably wouldn't work for my band as we have a loud drummer, and the required vocals volume would become too high. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted April 17 Share Posted April 17 It's often surprising how you can do things 'all wrong' and get away with it. In a way the possibility of PA behind the mics is what Bose were selling with their first stick systems. Although they advertised that this was due to the wide dipersal of line arrayed speakers the directional response of horns would actually help here in terms of feedback suppression. With both drums and keys between the PA speakers you could potentially point them either side of the front line mics which would help a little. The partial success of this arrangement (it doesn't work above certain levels) was more due to a smooth frequency response from their 'sticks'. One of the best things you can do to get a good sound is to reduce your overall volume on stage, and sometimes in the room. I can imagine a band who produce good but not excessive volumes will pick up extra gigs at some venues for that reason alone. Accepting a lower volume might be a commercial decision. A sound decision, not a sound decision I think not enough of us understand the concept of 'gain before feedback' Feedback only occurs when the sound from the PA (or any other speaker) returns the amplified sound at the microphone back louder than the original sound.* For any given system in any given room there's a level of gain which will give you feedback whatever you do. Set just below that point and the feedback from the mics can never build up and cause howlround. This band are just accepting that this point exists, turning up until they know where that point is and then working within that limit. You can change the gain before feedback in lots of ways, moving the speakers would be the obvious one, but if you are happy with the limit to your volume then what they are doing is perfectly sensible. Most of us I suspect don't line up behind the speakers in a rehearsal situation becaue we turn the gain down and don't need to. *Imagine a singers voice at the mic is around 90db it's then sent to the PA which adds 20db of gain and comes out of the speakers at 110db (90+20) Sound drops with distance so when it gets back to the vocal mic it's probably lost most of the 20db of gain ar maybe slighly more. This is crucial to feedback though. If it comes back at 89db then it's quieter than the voice and the sound will die away, if it comes back at 91db it will be amplified another 20db and come back at 92db which will be amplified again and again deafening us all with feeback. Anything slightly less than the original sound -no feedback, even the slightest fraction louder feedback every time. The gain before feedback is 20db in this case and you cannot use even a tiny fraction more. 1 Quote Link to comment Share on other sites More sharing options...
Downunderwonder Posted April 18 Share Posted April 18 Don't point the mic at the speakers. Don't have the speakers too close and aim them across the room to opposite sides so you catch enough to get by. Small guitar amps mic'd into the PA. No monitors makes life so easy. If you can't hear x or y, too bad! Only works when everyone is on the same less is more page. Quote Link to comment Share on other sites More sharing options...
Mottlefeeder Posted April 18 Share Posted April 18 In the busking band I play in, the BL likes to have one PA speaker at the front corner and one PA speaker in the opposite corner behind him as his monitor, but just doesn't get the fact that the back line have to wear hearing protection as a result of having a speaker so close to them. Although we play at relatively low levels, we often get feedback issues when the next front-person plugs in with a different mic to the previous one. I've probably spent as much on IEM gear as I have on my rig, just to keep the noise level down, and to hear what I am doing. David Quote Link to comment Share on other sites More sharing options...
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