Backstage intercom & show feed

[David Duffy]

This has more than likely been covered before but a search didn't turn up all the answers so...

 

A school I help at has a 225 seat auditorium with 2 classrooms behind that double as dressing rooms, etc. What they would like to do is have communication to those rooms from the control box at the rear of the house. Mostly the facility is used for drama but they are thinking of eisteddfod type events too.

 

For show relay, I had in mind a good quality CCTV camera that gives a view of the stage along with an aux feed from the desk that can feed backstage TV's via their A/V inputs. This is all straightforward and the classrooms already have TV's on carts.

 

What they also want is a paging system to advise upcoming acts to get ready, etc. I'm torn between an intercom (loud speaking or handset) and a simple ceiling speaker with booth god mic.

 

I can also envisage the need for (semi) private conversations between control box and backstage crew. Maybe they really need both.

 

Any comments on what is truly useful for both drama and eisteddfod / talent quest type of events? I do have a Clearcom style system myself but would rather install something more fixed in the classrooms.

[Don Allen]

A small pa amp like this from Altronics A4020 http://www.altronics.com.au/index.asp?area=item&id=A4020 with a vox mic input allows the remote god mic to automatically override the show feed. A separate talk-back outlet would allow a lot of flexibility for the ASM without the expense of wireless cans. Having several ceiling speakers helps to distribute the feed without it being too loud.

[robloxley]

You could do it all with a Canford Tecpro system but it's an expensive way to do show relay (you need a master station rather than just a PSU and Tecpro speakers backstage). How about a Tecpro system from control box to stage manager (& possibly to dressing rooms) for communication between crew, and a simple 100V line system with overstage and stage manager (and possibly control box) microphones for show relay/ cast calls to dressing rooms?

For camera a decent CCTV and signal splitter feeding the TVs via their AV inputs will work.

[matt_beal]

How about using transmitters and then a similar receiver at each TV. That way you can avoid running miles of cable, and have both sound and picture coming through the TV. The other possibility is if there are already active whiteboards in the class rooms, you may be able to use a spare input in the amplifier to do sound, and possibly same into the projector/dvd player. That way very little work required at all! I guess it all depends on whats already there...

[David Duffy]

Thanks for the input so far guys. Here's some more information and ramblings:

 

The VOX function on the paging/relay amplifier is a good idea Don. A compressor / limiter on the relay feed would probably be a good idea too. I'm not sure whether or not to install local volume controls in the rooms. I can see them being turned down to the point where they don't hear the paging. There are controls with an override relay so maybe that's the way to go to get the best of both worlds.

 

Installing the Clearcom outlets would be a good idea. Most of the cabling for it is actually already there. It just needs a little more work to pull it through to the dressing rooms and install the wall plates. They can then loan / hire a system for the few times a year that they really need it.

 

Having a couple of paging speakers over the stage for rehearsals could be handy too. I'd either use a separate amplifier or do some automatic switching to avoid the show feed from getting back to the stage area. Maybe a zone selector with illuminated buttons so that it's easy to tell where the god mic will be routed to. Installing most of the gear in the control box is probably the best place to ensure that it can be extended as the time arises.

 

They also want to route this system to the music block (50 metres away) but a couple of LIU's, the phone system cabling and a local amp should take care of that with a separate switch to select that zone as required.

 

I would rather go down the wired route if possible and not risk interference on via a 2.4HGz system. There is already a 40mm conduit running from the back of house to the backstage area so cable access is not really an issue.

 

For the show relay, I did think of a boundary mic attached to the lower inside edge of the proscenium (for shows not using any reinforcement) that fed directly into the relay/paging system.