Theatre needs quick help with acoustics..pics

Anybody who can help me PLEASE contribute! My theatre company lost our lease and has had to move our productions into this large church assembly hall. We have to open a week from Thanksgiving and they want me to "please help" with the acoustics... the building has a tile floor and concrete ceiling and walls. 85 ft long, 40 ft. wide, with (I am guessing) about a 20 ft. ceiling. Here is the layout: The tables will be removed and replace with rows of folding chairs... We have about twelve of these "chalkboards" to use as dividers, since we are only going to use half the depth of the space (seating about 120 persons: We can't place anything "permanent" on the walls or hang anything from the ceiling :cry: My first thought was ceiling baffles, but I guess that's out... The back wall... The side wall... We have 12 - 2'x4'x2" bass traps we salvaged from our old location and will be getting 4 - 12'x12' "rugs" to place in the seating area. I thought to place the dividers across the back of the seating area and then some angled along the side walls to help stop the bouncing reflections when folks are seated. Maybe some rolls of R13 stacked up in the corners? Perhaps hang our traps from the dividers to the left and right of the seating area? ANYBODY have any (cheap) suggestions? ~ Bill

maybe put the absorber panels on the chalk boards and use a couple chalk boards in the back. can someone make or donate long curtains/drapes to put in place of the short window treatments? the carpets should help a bit. if you can do drapes on each side, then run the carpets down the middle. people will also act as absorbers so consider saving one carpet for the stage.

Thanks Glenn, I hadn't thought about hanging longer drapes from the existing windows. They are only on one side of the room, but it should stop sound bouncing back and forth. Also a good point about the carpet. I suppose once the seats are filled the floor reflection would be less of a problem. I'll have to see if "set" changes will allow for the carpet on the stage. If not there, perhaps in front of the stage on the bare floor area in front of the audience (since they will be about 10-15' back from the stage lip). Here is a quick sketchup... take a look, any other thoughts? http://fld.server101.com/bat/theatre.skp

empty room > room with treatments Is this a good way to angle the dividers? Closer to the seats? To the walls? Maybe hang the bass traps inbetween the windows/curtains on the exposed wall and leave the dividers "as is"? I think we could do that by running a hanging wire from the window frames and hooking them to that. I still can't think of any way to hang anything on the opposite wall. Carpet (rugs) in front of stage. Do you think I should try and break up the floor in the area behind the seats with something? Put rugs down there? Put some tables back up with something soft on top of them in that area? Any thoughts?

:?: Bump :roll:

i would hang drapes on the other wall and across the back of the last row of seats (a few feet back actually) - in the back i would bunch them so they have openings and it increases the absorption of them.

Thanks for the help Glenn, I do appreciate it... ~ Bill

here's the sketch showing heavy drapes on each side as well as the back. if it were possible to hang some drapes up between the beams as well it might also help.

One word: ceiling ! You need to place absorbers in the ceiling to treat the execess in reverberation. And you also need to add diffusion to the space since large rooms with exclusive absorption treatment usually sound bad. There are several options here. Is this room dedicated to speech only ? Or more into music ? Now it is impossible just with pictures to have any idea of the reverberation time in the room. This could be 2 or 5 s, who knows ? The addition of acoustical material depends on the current reverberation of the room and the target reverberation. If possible you should try to measure the RT60 there and we will start from those values. If it is not possible to measure then the other solution (which is approximate) is to build an acoustical model of the room and try to evalute it. I can provide with an acoustical model of the room using specific software if you want to but feel that even with having the acoustical model you should try to make measurements in the room since the more accurate is the information regarding these values the more precision you will have on the final results. You are now dealing with a large room, forget about bass traps and other small room acoustics terms. This is a different subject, you don't treat large rooms like you treat small rooms.

I hear 'ya, and I completely agree, but...

CidyZoo wrote:

We can't place anything "permanent" on the walls or hang anything from the ceiling :cry: My first thought was ceiling baffles, but I guess that's out... We have 12 - 2'x4'x2" bass traps we salvaged from our old location and will be getting 4 - 12'x12' "rugs" to place in the seating area.

Thanks for the reply and your interest andrebrito. I will try and get some measurements. What we did helped a lot for Thursdays opening. I will post some pictures of what we ended up with. I am still trying to persuade them to add hanging baffles from the ceiling. I will let you know how this all turns out. ~ Bill