Loudspeaker delay in fairly small venue

[veen]

Ok, the venue is around 15m long and 5m wide with the stage at one end. In the past they've used a modest rig, speakers on poles at the front etc, and the sound at the back is rubbish/nonexistent.

 

I've been asked to recommend a system which will be permanently installed. One of my ideas is to install 3 pairs of speakers at various intervals down the room, ie at 0m, 5m and 10m from the front of the stage.

 

So this is my question to anyone who's done something similar in the past:-

 

If the budget is squeezed down, do you think it will be possible to get away without delaying the speakers, or will it sound completely crap?

[smalljoshua]

Imagine standing at the back of the room and hearing the sound 3 times. Once from the speakers closest to you then from the middle set then from the front set.

 

It will sound muddy and confused, like there is a bad echo in the room.

 

Josh

[bruce]

Josh's theory is fine. However it's a very small room. There's just 10m between the front and back speakers. That's a 30ms delay - not much.

 

You've already said that the sound level at the back from the front speakers is (your words) "nonexistent" - if that were completely true, then there would be no interference between the 2 sources, so adding any delay would be completely pointless...

 

Remember that when you calculate the "ideal delay", you're calculating it for one particular position in the room. In other locations, you may actually be making the problem worse.

 

It all depends on the acoustics of the room and the directionality of the speakers - in particular the reflectivity of the back wall - delays are one of these areas where it all looks great on paper, but you really have to use your ears. It could make things better, but there's also a real chance that adding a delay will make things substantially worse.

 

Try it and see... set the system up with the delay line in place, but the delay set to zero. Now increase it to the calculated value - using a guideline of 1ms per foot of delay. Now try it again adding an extra 10ms or so for the Haas effect. Listen critically - see which sounds best. Ask others. Walk around the room.

 

Sometimes when you're doing this, it all just "comes together" - however, sometimes you just turn the mush into a bigger mush...

 

If the venue were a little smaller, I'd say you probably wouldn't need delay, and if it were much bigger, I'd say definitely yes. But for that size, there's no way to be sure without trying it.

[johndenim]

It would depend on the overall volume and the application IMO.

 

This size room wouldn't take masses of SPL to fill it, I don't know the science behind it, but x3 sets at intervals would cover a lot better than 1 large system on/above stage.

 

If you were to install I assume the speakers would be on the wall?

I'm thinking you may not even need additional speakers if you could get a decent pair near the stage as high as possible.

I worked recently in a gala bingo hall, the speakers were tiny (6"?) and they were scattered all over the ceiling.

I don't think there was any delay added.

[Rob_Beech]

How high is the room.

 

As John says, if you can get the boxes high enough and have control over their vertical positioning (a flying yoke or similar) then you'll have NO issues covering a room of that size and significantly larger.

 

This is all of course, providing the speakers themselves are up to the job.

I've happily covered 60m x 15m with a pair of TQ445 (just 1 box flown per side on a yoke) without losing any significant speech intelligibility for the program material being produced. I've certainly covered over 40m without encountering problems with 1 box per side on 4m stands and flying yokes.

 

Ok, loud, expensive boxes, but you're looking at a quarter of that distance so you can instantly afford the boxes to be 12dB quieter. That brings you into the mid 120's.

 

Rob

[veen]

Imagine standing at the back of the room and hearing the sound 3 times. Once from the speakers closest to you then from the middle set then from the front set.

 

It will sound muddy and confused, like there is a bad echo in the room.

 

Josh

 

Thanks Josh, until you pointed that out I had no idea it was a possibility.

[veen]

Cheers Rob, the ceiling is no higher than 3m, I'm not sure how far back the sound could be thrown, although I was looking at these badboys Martin Audio W8VDQ, too much for a 200 capacity venue? Has anyone any experience with them?

 

One of the things I'm trying to do is cut the amount of sound leakage to the bar/restaurant upstairs. This is why I was thinking of spreading the speakers out, to avoid very high db levels in any one spot.

[Rob_Beech]

They're a box you need to have alot of experience with to get to work effectively.

[veen]

That's a shame, they could be a neat little solution. I'm not going to be running this system at all, and will just want to leave the venue to it. Therefore it has to be pretty idiot proof.

[back_ache]

That's a shame, they could be a neat little solution. I'm not going to be running this system at all, and will just want to leave the venue to it. Therefore it has to be pretty idiot proof.

 

If you want to make it "idiot proof" then feed the amps via a 2in 6out speaker processor, that will give you all the tools you need to get the most from the speakers (including the delays you want) and with the "lockability" to stop people mucking about with it. Two budget units I've used and are impressed with are the Electrovoice DCone and the Alto Maxidrive

[Kevin Ross]

Don’t forget the ubiquitous behringer ultradrive. 3 in 6 out with delay on each output but I would say that 3 delay rings in a bit of an overkill in such a small venue. Maybe have some just over half way back but you should be more than capable of covering that kind of size venue with good/controlled speakers combined with careful placement and aiming

[Matt Riley]

W8 is a very good sounding box. but, you're gonna need at least 2 a side. That's ten grand +amps (2 grand), cabling and not including flying hardware for what is probably what, a 100 seater venue. With unattended solutions, I'm a massive fan of not giving them incredibly super dooper expensive loudspeakers unless you absolutely have to. Investigate 1 turbo txd 12 or 1 martin f12 flown a side as a nice start.