A few weeks ago I was requested to set up a PA for a Pub's 10th yr bash. The gig was held in a long low room (9m x 3.5m x 2.5m high) with a 300mm deep ceiling beam cutting the room in 2 about 1/3 rd of the way down. The accoustic musicians of which I was one (guitars, mandolin, fiddle etc...) were sat in a semi-circle in the smaller end of the room (3m x 3.5m) with a low table twixt them and the audience. Mics (2x AKG 1000's were all I had spare at the time) were set c. 300mm below ceiling height pointing towards the musicians. Speakers were sat 3 foot off the floor (carpeted wooden) in front of the ceiling beam (ie at the opposite side to the mics). When the room was empty of punters it sounded fine. When the room was busy no one noticed the PA but you could clearly hear at the back. Result.

Had to do a similar thing on new years day. Same mics different PA. Next to useless. For some reason (possibly because the 'audience' were a lot noisier), all you could hear from the PA was audience chatter plus it kept howling when a double bass player and bass, stood next to one speaker.

As the landlord now wants a permanent instalation I have been charged with sorting it out.

I am happy with the mixer/speaker side of things (150W mixer amp ish, and two permanent wall mounted speakers on the beam, its only for gentle re-inforcement of the accoustic sound btw) but as to what mic's to use this is where I am struggling.

I think it would be best to ditch the high up position and go for a pair lowish down in front of the performers.

What do you think would be the most suitable type and position?

The system will only get used a few times a year so obviously I dont want to be spending large amounts of his money.

Any suggestions gratefully received.

If you use distance mics and manage to achieve a consistently good, stable sound in a busy room (I think unlikely) the audience will hear every whispered comment the musicians make. Is that really what you want?

Basic temporary pickups for stringed instruments and a few half decent mics would go a long way.

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Ohm's Law states, "Your PA isn't as powerful as you think it is".

Cheers Shufflebeat.

We normally play in the main bar amongst the punters, so whispered comments are not a problem.

The sessions are very informal, temp pickups not realistic, so what mics?

The howling with low instruments near a speaker is to be expected. The only way to fix that is move them away or use electric rather than acoustic instruments (or turn them down). The speakers couple to the resonating elements of the instrument.

With such a low ceiling, if you put the speakers up high, so that they project over the audience, you can easily run into trouble with comb filtering off the ceiling. If you were at the other end of the room the beam might help break that up, although it may also be too far back to give useful improvement.

I don't think there is any way to avoid micing individual instruments. You don't need to use contact mics or bridge pickups but they sure save a lot of hassle if you can. You might be able to get away with micing small groups of instruments if the players can be convinced to form compact groups.

The best solution if at all possible would be to put the musicians in the middle of the room. This will reduce the need for sound reinforcement and make the whole setting more intimate. You do need to be cognizant both of flow around the bar and evacuation routes when deciding if this is workable.

Cheers.

Quote damoore:

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The howling with low instruments near a speaker is to be expected. The only way to fix that is move them away or use electric rather than acoustic instruments (or turn them down). The speakers couple to the resonating elements of the instrument.

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Yeh...hence my

Quote damoore:

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With such a low ceiling, if you put the speakers up high, so that they project over the audience, you can easily run into trouble with comb filtering off the ceiling. If you were at the other end of the room the beam might help break that up, although it may also be too far back to give useful improvement.

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Cant imagine any comb filtering problems in that space and at the relatively low level of reinforcement needed.

Quote damoore:

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I don't think there is any way to avoid micing individual instruments. You don't need to use contact mics or bridge pickups but they sure save a lot of hassle if you can. You might be able to get away with micing small groups of instruments if the players can be convinced to form compact groups.

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We are in a fairly tight semi-circle, there was 11 of us inc the double bass in an area of 3.5m x 3m (and yes it was flippin cramped). What sort/type of mics?

Quote damoore:

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The best solution if at all possible would be to put the musicians in the middle of the room. This will reduce the need for sound reinforcement and make the whole setting more intimate. You do need to be cognizant both of flow around the bar and evacuation routes when deciding if this is workable.

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NOT possible, sorry.

Edited by Greenmanswaler (03/01/13 05:28 PM)

Ok. If your heard audience the second time, then the system gain was higher, and/or the audience was louder than before.
Also there will be different distances from the mics to the newer speaker positions.

As for mics, it won't make a huge difference, though I would expect to get a noticeably better result with my CAD 175s, rather than my C1000s, in that kind of situation ... See if you can borrow a couple of large-diameter cardioid condenser mics.

Below are some ideas with a diagramme of the room and band as I understand it.

Grey boxes: speakers on the walls behind the beam, pointing inwards and down toward the lower-rear of room.
Even better, do the Green arrangement with the box on the back of the beam, pointing towards the lower-rear of the room. Either way, the idea is to reduce comb-filtering reflections off the walls and ceiling. Try both ways; see which is most even.

Remember you are re-enforcing the acoustic sound from the band; often a centre-position can sound better than L-R arrangement, and also any delay you may add (see below, the arrows will make sense!) will be accurate for more listening positions in the room: You can imagine the arc from the centre-speaker is more representative to all the musos and the PA with the green arrow. Now compare the lengths of the black & grey arrows by contrast. You can see they are very different in lenghth ... but you can only choose one delay!

Delaying. If you can, delay the PA by the distance shown by the black (or green) arrows in feet; let’s say it’s 8 feet – that makes it roughly 8 milliseconds to align the speakers acoustically with the band. This means that (hopefully) the PA will ‘disappear’ and the band will be heard throughout the room much more clearly. You’ll get the best results by listening and adjusting the delay to around about (or a bit more) than the 'ballpark' figure given by the distance from the PA to the band. A second-hand speaker management/crossover box would be good for this, and you can also EQ out (just a few) problem feedback frequencies you will get with these rather useful devices. Hope that makes some sort of sense!



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PA stuff on FB

Guy....that makes a lot of sense. Please tell me more about your mic choice.

Hi, it's just that with those CAD 179s (oops, I wrote 175s above) I get a good sound without too much of the stage, in relation to other mics I've used.

They are also pretty good at the single mic/bluegrass band set-up as well.

However any good large diameter condenser on cardioid (often the best pattern for live) will be good.

And why I got two CAD 179s? For recording purposes—and then I tried them live and was very pleasantly surprised.

Also really good on fig 8 with live acoustic guitars with monitor in the null. And in cardi: flute and fiddle live ... loads of things!

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PA stuff on FB


Edited by Guy Johnson (15/01/13 12:32 AM)

Have only just read the above.

Cheers I will have a scout!

Drive by advertising removed. Read the PM that Hugh sent before you are tempted to revive more old threads. Andy

Edited by zenguitar (18/02/13 11:52 AM)