Sound needs in a black box theatre

Discussion in 'Location Recording' started by pmolsonmus, Apr 24, 2009.

  1. pmolsonmus

    pmolsonmus Well-Known Member

    Hi All,

    It's not worth the rant that it deserves, but despite the fact that our school is doing a 60 million dollar rennovation we still will not have an auditorium in one of the (if not THE) wealthiest districts in the state of Wisconsin.

    We are, however, going to get a small gym converted to a black box theatre. The plan is to get a space that will seat about 250 in folding chairs in multiple configurations.

    I've done sound in a number of different set-ups in a wide variety of settings, but they are asking for input in the planning stage of this space. Whether they take my input or not remains to be seen, but we'll give it a shot anyway.

    I know what I would typically use for my needs, but wondering if anyone out in RO land might have some additional thoughts if designing from the ground up.

    The space will be used for concerts, plays, Madrigal Dinners, open mic-type events, etc... No stage, just a space.

    I am told there is to be a centralized grid suspended from the ceiling and a light and sound booth.

    Let's assume money's not an object for the time being. What would you put in the space and how would you have it configured?

    For my sound needs I would like to have a booth, but also the ability to put a board in the room at any location to be able to feed speakers that are not in a fixed location. Is there a smart way to do this? Hardwired snakes on all 4 walls?

    Other thoughts?

    I'm not worried about mics, rather the basic set-up, speakers, electronic and operational aspects of a space like this.

  2. TheJackAttack

    TheJackAttack Distinguished Member

    I was on an install as a worker for a new building project at a SoCal college. We put in a speaker panel at each of the four corners and a separate box for a basic six gang XLR plate. Each of these ran in independent conduit to a central point in a service hallway and was tied together. The speaker lines connected to amps right there in a rack and then ran out to the ceiling area where we had suspended what I remember as Community speakers. (It has been almost seven years so my memory may be suspect)

    The end result was that someone could take a basic rolling rack with a 1642 VLZ mixer, CD player etc and roll to whatever corner of the room was best for the presentation/dinner/play/etc and run a show.
  3. dvdhawk

    dvdhawk Well-Known Member

    Hi Phil,

    Funny how there's never any shortage of money for sports, but most schools can't scrape together a few thousand bucks for the arts. Is this the direction of your rant?

    I can throw together a quick recommendation, but I'm going to need some dimensions.
  4. pmolsonmus

    pmolsonmus Well-Known Member

    Hey hawk,

    I could give you the exact measurements of the current room, but (of course) we're not getting the WHOLE space. And even if they gave me a number today I wouldn't trust it to be what we might end up with. So...

    For arguments sake, lets say a rectangular space, 50' x 100'. It should be somewhere in that ballpark. (pun intended)

    Assume a grid in the center for suspended lights/ speakers?/ etc... All electrical and lighting/sound needs will need to be addressed now so at the very least the electrical is in place even if the fixtures for light/sound are not yet purchased.

    Is that enough to go on?
  5. dvdhawk

    dvdhawk Well-Known Member

    Hi Phil,

    Sorry, I didn't get this into the earlier post, but I thought of some relatively important follow-ups:

    Ceiling height? - standard gym 25-30ft high ? (tiles, or steel trusses?)

    Do you expect to presenting with your back to the short wall or the long wall? How versatile does the sound configuration need to be?

    Will there still be basketball and/or volleyball or other sporting activities in the room?

    All hard surfaces? Is it going to still sound like a small gym?

    Elementary, Middle School, High School? (so I can take into account how big their voices are - how much gain before feedback will you need).

    Thanks again.
  6. pmolsonmus

    pmolsonmus Well-Known Member

    Ceiling height is still "to be determined" but there is currently a balcony weight room that is being converted and walled off so height should be at least 30 ft. but of unknown (trusses/tiles) origin at this point.

    The plan is to be able to use the space in any possible combinations so JackAttack's suggestion for an amp in each of the 4 corners sounds like a good one to allow for any configuration.

    This will no longer be used as a gym (that's where a huge chunk of the $ is going- 4 new ones!) so at least its a crumb given to the fine arts departments.

    BTW this is a high school (yes a high school in a very affluent community without an auditorium)

  7. TheJackAttack

    TheJackAttack Distinguished Member

    The amps were all in a tall lockable rack enclosure with proper fans/ventilation. All four room corner panels tied into this rack (and a littler one beside it for mic lines) and from this rack the amp output ran up to the ceiling where the speakers were flown. If I remember right, we had nine bus bars that we tied the speaker lines to (10/3 or 12/3 wire). The bars were mounted on a panel that screwed into the rack. I made a knock-out in the rack and mounted an external lighted power switch for the power distribution. Basically, once I had it all wired in and the amps set up I locked the cabinet; labeled the keys; and hid them in the building managers office so no one could be helpful at some unforseen future date.

    The ceiling in this room was pretty tall. I remember I had to rent a tall scissor lift to fly the speakers and it was extended all the way.

    Basically we made the best of a bad room.
  8. pmolsonmus

    pmolsonmus Well-Known Member

    I just found out they would like an answer by Tuesday afternoon so any additional input would be greatly appreciated.

    My thoughts are to put a rackmount amp in each corner. ( [ A-D ] )
    Speaker outputs via 1/4" to speakon connections so the speaker can be mounted in any configuration (speaker stands, on the floor, or flown from the grid)

    Then 4 permanent breakout XLR boxes (6 balanced inputs - 4 1/4 inch send/returns) on each wall. These would go to the sound booth -

    A 24 Channel mixer with 4 buses should meet just about any need. I'm assuming with this configuration, we could run the show from the booth or run a snake from the booth to a board placed anywhere in the room and send the stereo mix back to the booth to drive the amps. Ideally a breakout box outside of the booth with sends would be a good idea yes?

    Sound feasible? Suggested power? Problems?

    I tried to create a picture but it isn't working.
  9. dvdhawk

    dvdhawk Well-Known Member

    Hi Phil,

    Even though there's no graphic, I think I understand what you're saying about Corner A, B, C, & D. So at any given time you might be presenting from one wall and using the amps and speakers from Corners A & B, while Corners C & D are idle.

    Given the wide variety of configurations you're planning for, have you considered good powered speakers? In your case that might be what I would propose.

    It would

    A) simplify your install
    B) simplify your set-up from event to event,
    C) give you maximum flexibility in terms of configuration with very little effort and no special cables or connections
    D) I think in your case save you money in the long run.

    All you need is a balanced cable for mains to several locations in the flying grid and an electrical supply exclusively for the cabinets. (clean home-run circuit or two - not tied in with the lighting) Powered speakers will give you endless options for monitors too.

    Mic cable is cheap compared to pulling twice as much 10 or 12 AWG speaker wire and the SpeakOn connectors, and buying four amps and racks when you only need two at a time - it may save you some money to spend on the system elsewhere. The racks and enclosures for amps in the 4 corners will really add up fast. It's crazy what they get for a small steel rack these days.

    I'm working on a sketch in what little spare time I have. I see you've got a deadline - so I'll do my best to get this finished and uploaded later today.
  10. TheJackAttack

    TheJackAttack Distinguished Member

    Powered speakers are a good idea. I like it.

    One reason we went with a central amp rack was that was the only way we could control folks not spilling/piling/blocking air vents/etc for a bunch of separate racks. Also, though it cost more, the enclosure we used for the amps and wiring was 72" tall. No one was going to block that or spill coffee on it.
  11. dvdhawk

    dvdhawk Well-Known Member

    Hi Phil,

    A room that's 100 x 50 x 30 is going to have some issues, I honestly don't think there are huge advantages to playing to the 100ft. or 50ft. dimension. I'd be inclined to go the short way and use wider dispersion, keeping the audience closer to the stage area and closer to the speakers might offset some of the acoustical problems.

    After thinking about this and drawing it up several different ways today, I'm still convinced powered-speakers would be a good fit for you. Maximum versatility being the biggest advantage in my mind. They are extremely scalable with no concerns of impedances or loss over long speaker cable runs.

    Throw 2 on tripods and put one down for a floor monitor and you've got a small system together very quickly. OR Hang 3 from the trusses L/R/C and you're good to go. Put in a powered-sub, now or later - doesn't matter - just keep stringing them together.

    It would make the install relatively easy and just require an AC receptacle and XLR panel in any area(s) you anticipate placing speakers - whether it's on the floor or in the trusses. Since you won't be using more than one set at a time, you could either actively split them or tie the XLR panels together passively and be OK if they're well shielded.

    Ground Stacks (or Tripods) would obviously be easiest to reposition and reconfigure. I like the sound of stacks at stage level - it helps my ears match what my eyes are seeing - the sound is coming from the performer on the stage.

    Suspended Center-Clusters are great if you have very aimable speakers. To get the right dispersion from a center cluster you would need to decide whether you are throwing the 100ft. length of the room, OR the 50ft. wide version. I don't think you could do both layouts justice with the same cluster. You would need +180 degrees of width the wider way and more like 60 degrees to shoot the long way.

    Left / Right (optional Center) Individual Speakers would be nice if they aren't split too far apart and not hung too high. Get something with a tight horn pattern.

    Left / Right Line Array might be OK too, but probably most effective if you were projecting sound the 100ft. direction. Their natural curvature gives you nice downspill and nice even coverage from the front of the room to the back with nice cohesive high-end although their pattern might be a little wide for your room. You can put your Line Array on the floor too -but now they curve up. Line Array mounting brackets are usually heavy and expensive.

    I would hope that if suspending either L/R(C) or a Center cluster you could get them hung down to a reasonable height. I don't like being seated in the first few rows and being aware that the audio is coming from over my head. Unless there are extenuating circumstances, I don't like the bottom of my cabinets to go any higher than 20ft above the floor in a small auditorium.

    I don't know how many channels of snake you anticipate needing, but if you're still thinking about the ability to present from any wall- I'd split half to the center of a short wall and half to the center a long wall. Commit to 2 walls and go with Plan B below. Surely there are exits you'll need to keep clear. You can always put beefy multi-pins on multiple walls that tie to the same places, but quality multi-pins get expensive real fast.

    My school clients these days are probably 98% wireless handheld and lav mics - with the exception of the hanging choir mics (which I detest anyway) and a couple lines for DI connected to a keyboard or whatever. The few that have mic jacks in or on the stage rarely work. They have been kicked, stepped on, and neglected for years and no surprise aren't very reliable after years of abuse. Anything you're putting anywhere near kids has to be virtually bullet-proof. If they can reach it, they can destroy it.

    PLAN B:
    If you don't like the idea of powered speakers, I'd commit to 2 walls, one long and one short and put a single amp rack in the common corner and wire the speakers to it and leave enough extra cable on the snake to reach mid-way up either wall. You would make that a "mic only" snake (no returns) and hardwire the returns separately so they don't have to come from the stagebox in this case.

    Then hang the appropriate speakers for each of the 2 orientations. I wouldn't want to be repositioning speakers 20-30ft. off the ground for each production. Even with a scissor-lift it's a chore - and a risky one at that.

    Again get something very aimable, for non-powered speakers I'm partial to the JBL AM6212 series cabinets. Three horn patterns to choose from (60x40 / 90x50 / 100x100 I believe) and they are rotatable horns - so for instance it can be 90 degrees; wide and 50 degrees high or rotate the horn and they go to 50 degrees wide and 90 degrees high. You can mix and match, that way you can limit reflections from nearby walls and avoid excessive lobing where the high-frequencies overlap in the room. Another advantage is that you can orient the cabinet vertically or horizontally and still get the horn to throw where you want it. You would hang them so they're angled down to the front row. The angle is determined by the horn pattern. I'd also recommend hanging them horn down to get better clarity to the front row- you don't need a bunch of high-end bouncing around the rafters.

    At one point you said, "let's assume money is no object", well....

    If I needed maximum flexibility and had the budget I'd use ground stacks of JBL self-powered VRX or PRX cabinets, to cover both your amp and speaker needs. - Including monitors. 1st Alternate Plan B JBL stacks of SRX and a rack full of Crowns, DriveRack and sequential power conditioner.

    I'd consider a digital snake - A/D & D/A converters using Cat5 - you can put Cat5 RJ45 jacks all over the room if you want. (not to mention the unlimited monitoring and remote mixing capabilties) *NOTE this Audio Cat5 has to be an independent system, it cannot be tied in any way to a computer/data network Cat5 system. 1st Alternate Plan B snake.

    You could go nuts with wireless mics and lavaliers and almost forego the snake completely. You might want a handful of hardwired mic jacks for instrument mics, DIs, etc. In any case you'll want to hardwire your returns for Mains and Monitors to wherever you are likely to put speakers or amps - either on the walls or in the trusses.

    I've put in a couple systems with a rolling cabinets for the mixer/EQs/wireless receivers/compressors/CD players, CD recorders, etc. All they need to do is hook up the electric and a big multi-pin to tie into the sound system. It's a 20-second set-up and has the ability to be rolled away and locked up just as quickly.

    Hope that is of some help. Not much time to do anything else.

    Good luck, I hope they give you some money to work with.


    Some sketches of how this really simple set up could handle just about any set-up:






  12. pmolsonmus

    pmolsonmus Well-Known Member

    Thanks for all of the work Dave! This is why I started hanging out at RO to begin with - great knowlegeable and helpful people.

    You convinced me on powered speakers (I was beginning to lean in that direction because some idiot kids just blew a channel in a Crown amp I had set up in our current space). CD player/mixer/snake/amp/ speaker. It was all wired and operational - I checked it myself. I come back 3 days later because they had problems after the "lighting guy" helped them with the set up to find a channel blown and it wired differently. :evil:

    At some point we may want to use the space for theatre-in-the-round and we will likely perform a Madrigal Dinner in the space with a stage on one side and a "court" on the other. I'm thinking wall plates on all 4 sides. 6 XLR balanced in, 2 balanced outs and 2 - 1/4" outs should suffice, yes??

    My thoughts were originally on the JBL PX series 4 -2 way mains, 4 monitors and a sub (if absolutely necessary). In a room that size it should be more than sufficient for our needs.

    I hadn't thought about a Digital Snake using CAT5. My knowledge of them is minimal. Even if we aren't at the Digital mixing board stage now, it probably wouldn't be a bad idea to have the wiring capable yes??? Is that what you're thinking? Run the cable now to the booth, add the snake (built in preamps yes??) and a digital mixer/computer to control later?

    Other thoughts - I can handle the mics - I have choral mics, PZMs, PCCs, SDCs, LDCs.

    Inside the booth I'm assuming a 24/4/2 mixer, Graphic EQ, Digital Reverb, and the ability to patch in/out to a FOH board anywhere in the room.

    I'm considering the portable mixer unit w/ CD etc...., but I'm a bit fearful that it would be used by too many people who don't know what they're doing and I would end up repairing, damage control or replacing what others have access to. Thoughts??
  13. dvdhawk

    dvdhawk Well-Known Member

    Hi Phil,

    I'd rather see 4 XLR returns, but I guess I could see some value in a 1/4 in a few places"

    I think that's a good idea. If you're looking at the PRX 515 15" 2-way you may not need the sub unless you really want to rattle the rafters. The PRX are pole-mount only and don't have any attachments for flying them. In that case you can use the sub as a base with a straight pole, or go to tripods.

    If suspending them is a priority, the VRX series speakers are flyable and/or tripod ready - and more powerful, and also more expensive.

    Cat5 / Cat6 cable can be used for all kinds of audio & video and is so cheap I would pull at least one or two unshielded Cat 5 to several locations and maybe a run of shielded too. The potential number of things you can do with it now and in the future will be well worth the relatively small expense.

    You can use a digital snake with an analog mixer, but in addition to the A/D on-stage you need the D/A converter breakout at the mixer - both the input modules and output modules come in increments of 16. [up to 64 total channels passing through one Cat5 - with the addition of a bridging device] That would be digital from the stage to the FOH mixer, but it's still best to have hardwired analog returns in most situations. This kind of digital snake will cost a little more than conventional snake, but if you were pondering something like a high-quality Veam multipin at several locations that will be several hundred bucks to install each connector - and when you add numerous runs of multi-conductor cable the bottom line would quickly tip in favor the digital snake via cheap Cat5/6. That's the only reason I mentioned it, thinking it might be a good alternative to multiple costly multi-pin ports around the room.

    This is the one I'm most familiar with:

    That all looks good to me. I'd also consider something like a dbx DriveRack PX as the last thing in the chain - which with an RTA analyzer mic will let you EQ the room flat in a minute or so, no matter where the speakers end up. And it can give you a nice limiter to keep someone else from blowing the roof off the place. I usually like to put in a sequencing power conditioner in schools and churches to make sure everything gets turned on and off in the right order. Compressors and EQs are always a plus if you can keep "lighting guys" and "idiot kids" from touching them.

    You are absolutely right to be concerned about that. As a rule the portables I have out there on installs roll away and are locked up after the performance. They're multi-pinned so it's one AC extension cord and one Veam plug the size of a soup can. [the whole thing is very durable and idiot-resistant*]

    *I've learned there is no such thing as idiot-proof. A determined idiot will always find a way to screw things up.

    Good luck Phil, let me know if you have any other questions.

  14. pmolsonmus

    pmolsonmus Well-Known Member


    Room is almost functional. Actually we had our first major show this past weekend - a musical revue. The space is actually about 60 x 40 and can still seat about 250 with a decent size stage area. There are some real issues with what the architect and contractor did in the room (no time for that rant) and in reality really made the room difficult to light. They installed 8 x 8' acoustical "clouds" (steel studs and drywall) over 2/3 of the ceiling with dimming flourescent lights. They clearly intended for this to be a concert/classroom type space with the 60 ft wall being the focal point. They put the clouds suspended from the ceiling and blocking much of the area where we planned a lighting grid and the line of clouds closest to the wall is angled at about 45 degrees. (right where you would want theatrical lighting to light what they created as the front of the room.) We got them to remove some of the center clouds and are proceeding with a new plan for lighting but have yet to really address the sound issues. I have to say the acoustical treatment and the ceiling height 40+ ft and wooden floor make a very nice sounding room for anything. However....

    Right now there are 5 standard outlets in the room and no wiring of any kind even though there is a light and a sound booth. All cabling at this point will need to be added and it appears that we would only use 2 walls as the "front" or a theatre in the round set up. That said, any changes from earlier suggestions? If we go with powered speakers, I truly believe we will need to add additional outlets in addition to the wall plate break out boxes. I still like the idea of adding Cat 5/6 and also think a standard coaxial connection in several locations so that we could send a video signal to a green room and audio. Do audio via A/D to the Cat 5 with a plate in the green room?
    I'm thinking given the lighting fiasco with the grid situation that suspending speakers and cable is probably not a good idea and that a tripod situation is probably the way to go and just have mic ins/speaker outs clearly labeled with an amp or two in a locked rack in a back room.

    Everything else is kind of up for grabs. Thoughts? Suggestions?

  15. dvdhawk

    dvdhawk Well-Known Member

    Hi Phil,

    Glad to hear you're making headway.

    I agree with you, you'll need more electricity - at least a few more circuits around the designated stage area. Not to mention something to feed theatrical lighting dimmers.

    Depending on the distance to the green room, you might want to use cat5/6 with A/V baluns for that too. You can run just about anything through cat5/6 cable these days with the right interface (balun) at both ends. The baluns range from $35 to several hundred, but weighed against the cost of long high-quality well-shielded video cable it's usually pretty even at the bottom line and a lot easier to pull.

    I'm not sure why you will need "an amp or two" in the back room if you're using powered speakers all around. If you keep with all powered speakers you can use all XLR wallplates. If they're gendered the right way [females to the mixer, males returning back to the speakers] you should be pretty safe from mis-wiring problems.

  16. pmolsonmus

    pmolsonmus Well-Known Member

    Not sure why my post got deleted, but...

    There are doors on 3 of the 4 walls in the space. A total of 5 entries, 3 double doors - 2 designed for audience with a double entry, a double "stage door" and 2 additional single doors to a back hallway (backstage storage type area), One of the 40' walls and the wall with the light/sound booth will always be used as the back of the house. If we go with powered speakers even if we add additional outlets, we will likely run into a fire marshall issue with A/C running across foot traffic as fire exits for performers or audience because of the number of doors in the space.

    I'm leaning back towards standard speakers because of that problem. I realize we can always snake cable above doorways, but I'm not sure if that is the best option. I will look into the Cat 5/6 option and am putting that as a high priority for the eventual wiring as well as break out boxes on the two "front" walls - probably 2 on the 60' wall and 1 on the 40' wall with ins and line outs as well as feeds to the light/sound booth. Thoughts?

    I'm also thinking we'd probably want the option in the light/sound booth to have those XLRs routed to the board in the room or to another return on the far 40' back wall so we could have a soundman in the room for concerts/shows as well. Would that be best done by a hardwired snake in the control booth? In other words Channel 1-24 is wired to the mixer in the control room, but an additional 16 channel snake would be accessible in that room to send those same inputs to a mixer in the house instead. Am I making sense? Is there an easier way? The light/sound booth is floor level and is not a great place to run lights or sound from.

  17. pmolsonmus

    pmolsonmus Well-Known Member


    any thoughts Dave or others?

    The real problem I forsee with powered speakers (they're recommending the new QSC line) is the power itself. How do I plug them in without running A/C parallel to the speaker cable or in front of lots of doorways with 5 exits in the room?

  18. dvdhawk

    dvdhawk Well-Known Member

    Hi Phil,

    I've stewed on your problem since you posted the question. I just haven't thought of any great solution that addresses all of your issues.

    Maybe you could use a power reel like you see in a professional garage.

    The only caution I'd add is that in a school environment I'd make them retract 4 times higher than Michael Jordan can jump. I've never seen a teenage boy that could resist trying to jump up and grab something that's even close to being within reach.

    You would have to use a ladder or telescopic pole with a hook to lower it.

    I don't know, it might be a bad idea around teenagers in general. It may turn into a Tarzan swing too....

    Just thinking outloud....
  19. pmolsonmus

    pmolsonmus Well-Known Member

    Well one problem might have led to an alternate solution. Because of the "cloud" situation they are now looking at strictly pole mounted lighting in the corners and walls and forgoing any grid whatsoever. This creates another issue when trying to hang a backdrop, but I digress.. We're working on that one too.

    Not sure if this will work, because it goes against what I have usually done with audio/lighting and that is avoid shared powered but...

    There will be work light outlets that although on the poles that will be hard wired, will not be directly sharing a dimmer with any adjustable lights (in other words not controllable by the light board)

    If those are run on a separate circuit, even though it comes from the same 225v supply, would I be able to plug in powered speakers in the work light outlets??? Would that nasty 60 cycle humm be forever in my PA?

    I'm not anything close to an electrician but I know enough about electricity to know that it will find a ground in its easiest path, would that be my cable as a result of plugging in with shared lights?

  20. pmolsonmus

    pmolsonmus Well-Known Member

    Here is a pic of the room if it helps

    stage area would be to the left of the photographer for the 40' wall as front set up, or behind the piano for the 60' as front set up

    Picasa Web Albums - Elmbrook PR - BCHS Construc...

Share This Page