Loudspeaker placement

[Johnno]

I've been given the go-ahead to arrange for the loudspeakers in our school hall to be moved from their present home either side of the stage to anywhere I want them to go. We have Carlsbro cabs that need moving as they are too close to the mics (and quite ugly to look at!).

 

The other speakers I've got and the ones I was thinking of using are JBL 8SRs and I have four of them with fully steerable mounts. It isn't an option at present to get a better/more appropriate speaker but they can be put anywhere I say they should go and I'm wondering where's best.

 

I've been considering having them installed on a roof beam up near the ceiling (height 18'), centrally, about 10' in front of the apron. Normally the front row of the audience is at about this distance from the stage. Would mounting generic loudspeakers in such a position - as opposed to arrays etc designed to be flown - be likely to give better results than their being hung on the side walls of the hall (width 50'), which is probably the only other option?

 

The wall of the hall opposite from the stage can be opened out into the canteen to give a bigger hall and there are a further two Carlsbro cabs hanging on the canteen side of the shared wall. The opening width is around 25' and offhand I think it's not the full hall height either, although it is considerable.

[Bobbsy]

A centre cluster is generally a good way to go, particularly if you do a lot of speech-based reinforcement. Clearly you won't get much cover of the first few rows though. I believe you once said you had 4 JBL speakers...it's not too unusual to put a couple of speakers flown in the centre and two more either side of the proscenium to provide some extra fill at the front. The Court Theatre at Pendley in Tring (near me) has this sort of configuration and it works reasonably well

 

The caveats: I've never used the type of JBL you mention. If they're not designed for flying, approach this with extreme caution. It's possible to design cradles for non-flying speakers but this is a job for somebody with the necessary engineering/rigging qualifications to give you a result your insurers will be happy with. The rig will almost certainly want to have an adjustment for horizontal and vertical angles so you can experiment with the coverage. The dispersion angles of the speakers are fairly wide, so overlap (with possible comb filtering) could be an issue; a rig that lets you play with the angles will help you minimise this.

 

Edit: I just dug out that spec sheet link I posted for you in a previous thread, and it mentions the availability of wall and ceiling mount brackets for your speakers, so that's one less problem for you.

 

Finally, the extra speakers for the canteen: This could work, but you'll have to use delays on the feeds to these to compensate for the difference in distance. If they are delayed so the sound from the main hall arrived a couple of ms before the canteen speakers, the sound should appear to be coming from the front.

 

Bob