1918 silent theater asking for audio recommendations.

[JohnnyAudio]

Our local theater is looking to upgrade its audio system. The room is 84' X 18' X 12' high, a shoe box shaped room, not classic theater shape. A drawing is attached.

Right now the room sounds pretty bad.

Behind the screen there is speakers, Left. Right, Center, Sub. There are 6 surround speakers on the side walls.

The side walls and rear wall are drywall, covered with indoor outdoor low shag floor covering. The floor is epoxy covered concrete.

A Dolby CP750 Digital Cinema Processor is used to feed 2 Crown XLS2000 power amps.



I am asking the team here for recommendations to improve this theater.

My thoughts are to add more sound absorption material to wall and perhaps the untreated ceiling to start with.

They can keep the Dolby and amps. The owner is asking for a JBL system but the cost maybe too much.

We would like to improve the intelligibility of the sound.

The surround sound is horrible, but the owner wants to keep it because, "that's what people expect".

This theater used to show fine art films but now it shows kids animation and action movies.

Can anyone make some suggestions that may improve this very odd shaped theater?

 

[staticV3]

Can anyone make some suggestions that may improve this very odd shaped theater?

Look up silent disco.

If that's not an option, then the best setup I can think of is to place CBT column speakers in the front corners of the room, then use beamforming and perhaps crossfeed cancellation a la BACCH (not sure how viable given the diverse listening positions) to give everyone the best stereo experience within the limitations of the room.

More here:
https://trueaudio.com/array/
https://www.audiosciencereview.com/forum/index.php?threads/murphy-corner-line-array.25090/
https://www.audiosciencereview.com/forum/index.php?threads/murphys-corner-line-array-project.25983/

Double bass array would likely also improve intelligibility without sacrificing LFX.

For surround sound, perhaps a second pair of columns placed in the rear corners, but calibrating and optimizing such a setup I'm sure is no easy feat.

Consultation from https://www.holoplot.com/ would likely be valuable.

 

[Speedskater]

The folks at the Pro Sound Web forum might have some input:

ProSoundWeb Community - Index

ProSoundWeb Community - Index

forums.prosoundweb.com

 

[Philbo King]

In a space like that I would start by measuring T60 vs. frequency and do a modal analysis to determine the type(s) of acoustic treatments might be needed.

 

[audio2920]

What are the current LCR speakers? (Sorry if already mentioned somewhere)

 

[kyuu]

silent theater asking for audio recommendations

 

[JohnnyAudio]

What are the current LCR speakers? (Sorry if already mentioned somewhere)

The L/R speakers are unknown. The center is a Voice of the Theater, the sub is on old EV.
The surrounds are Optimus. Just kind of thrown together.
A nice JBL system would be a good choice.

 

[JayGilb]

Measurements maybe difficult due to such a long rectangular shape.

Ask the owner if you could get a personal showing where you could move around the room and take notes on different locations. Yes, it will vary when full of patrons, but it might help identify weaknesses.

 

[Philbo King]

Measurements maybe difficult due to such a long rectangular shape.

Ask the owner if you could get a personal showing where you could move around the room and take notes on different locations. Yes, it will vary when full of patrons, but it might help identify weaknesses.

IMHO, the empty room would be worst-case, with acoustics improving as people filled it. But certainly worth consideration.

 

[JayGilb]

IMHO, the empty room would be worst-case, with acoustics improving as people filled it. But certainly worth consideration.

I agree with you, it’s just hard to do with a crowd.

 

[JohnnyAudio]

Measurements maybe difficult due to such a long rectangular shape.

Ask the owner if you could get a personal showing where you could move around the room and take notes on different locations. Yes, it will vary when full of patrons, but it might help identify weaknesses.

I've been in the theater with and without people in the seats, it's pretty bad both ways.
If the theater was mine, I'd go with a simple L/R stereo system and forget the surround sound. The room is small, it doesn't need a powerful and complex system.
Maybe a wireless headphone system would be most intelligible but I don't know how the patrons would like it.

 

[Archguy]

Maybe a wireless headphone system would be most intelligible but I don't know how the patrons would like it.

They'd hate it because it would interfere with their incessant yammering during the show, not to mention cell phone conversations.

BtW: I like that off-center aisle because it permits a number of prime seats right on the center axis! And the seat pitch is awesome, especially for us tall guys.

 

[JeffS7444]

I have no particular experience with situations like this, but I wonder if, rather than one large set of speakers, you had multiple, smaller "zones", if you could solve the intelligibility problem, and not have to blast the front row with a wall of sound.

 

[ThatSoundsGood]

So, this is going to be a tough project because the low ceiling keeps you from getting the coverage to the back of the room. It's possible to use a small line array (maybe 3-4 boxes per side) to try and get more even coverage front to back. That's what I would likely propose but I would have to draw out the room and see if it would work. Is there anywhere that you can hang a couple of hundred pounds on each side? Have I already blown the budget?
It is also possible to have an additional left/right speaker on the side walls about 40-50' back in order to get coverage to the back of the room. But this has to be properly delayed by a professional or it will just cause additional problems.
The big problem here is that if you turn it up loud enough for the people in the back, you excite the room so much that it will all just sound terrible everywhere.
If the guy in charge thinks that a brand like "JBL" is the solution then he might be missing the point here. There is no brand that be substituted for a professional installation job.

 

[ThatSoundsGood]

If budget is an issue (which it often is), I would get something like this:

Mackie SRM-Flex Portable Column PA System

1,300-watt Column PA System with 10" Subwoofer, 6 x 2" Line Array, 6-channel Mixer, Bluetooth Streaming, App Control, and Onboard Reverb

www.sweetwater.com

I would get the top columns up as high as possible and maybe point them down just a bit so that the top of the vertical coverage hits the back of the room. I used to install Bose MA12's all of the time in churches like this and it was the most effective solution. This problem with a lot of these is that they have a really wide horizontal coverage, which doesn't fit your need here. This specific Mackie that I provided a link for has a narrower horizontal coverage and that will keep the energy off of the walls better. These columns are line arrays and they do better at keeping the coverage more even across the front and the back. They don't sound great for a full band or anything like that but they will be good for movies. You can always buy it somewhere that has a good return policy so you can try them out.

 

[JohnnyAudio]

If budget is an issue (which it often is), I would get something like this:

Mackie SRM-Flex Portable Column PA System

1,300-watt Column PA System with 10" Subwoofer, 6 x 2" Line Array, 6-channel Mixer, Bluetooth Streaming, App Control, and Onboard Reverb

www.sweetwater.com

I would get the top columns up as high as possible and maybe point them down just a bit so that the top of the vertical coverage hits the back of the room. I used to install Bose MA12's all of the time in churches like this and it was the most effective solution. This problem with a lot of these is that they have a really wide horizontal coverage, which doesn't fit your need here. This specific Mackie that I provided a link for has a narrower horizontal coverage and that will keep the energy off of the walls better. These columns are line arrays and they do better at keeping the coverage more even across the front and the back. They don't sound great for a full band or anything like that but they will be good for movies. You can always buy it somewhere that has a good return policy so you can try them out.

Dear Soundgood,
The Mackie SRM looks like a good solution. They would have to reside behind the screen as there is no room on the sides in front of the screen. The narrow horizontal coverage would probably work out well. The price of $899. each is within the theaters popcorn budget. Maybe a couple of side fill speakers placed in a good location would help, like a EAW JF60 type. I don't care much for DSP's but I may have to use it here. There is a music instrument store a few doors away that may have the Mackie system. We could put it in for a trial and add sound absorption as required.
Thank you for the solid advice.

 

[audio2920]

Just a few thoughts for you to take with a pinch of salt as I am neither an acoustician nor PA system designer....

1. In my experience mono (or more specifically; center) is usually best for dialogue clarity in large spaces.

I've always assumed this is because L/R can have significant time misalignment depending on the seating position. So (a) you get a 2nd direct signal with late arrival and (b) the reflections are also more complex and messy. But there may be more to it.

2. If the screen has an old school 'standard' pitch perforation, anything other than a large horn for HF can be problematic when placed behind it.

Again, I don't totally understand the physics, but I assume the perforations cause interference patterns at some frequencies and the solid part causes internal reflections between the screen and speaker, also with interference patterns, at HF. Maybe... Anyway horns seem not to suffer as much with these coarse perforations.

3. I do think given the length of the room and high costs involved in getting into acoustic treatment on this scale [and doing it properly] a well thought out speaker system might offer better value for money.

 

[JohnnyAudio]

Dear 2920,

Yes, the screen has an old school 'standard' pitch perforation, anything other than a large horn for HF can be problematic when placed behind it.

This is true with the existing center speaker that is an old school Voice of the Theater.
Thank you for your opinion.

 

[ThatSoundsGood]

Dear Soundgood,
The Mackie SRM looks like a good solution. They would have to reside behind the screen as there is no room on the sides in front of the screen. The narrow horizontal coverage would probably work out well. The price of $899. each is within the theaters popcorn budget. Maybe a couple of side fill speakers placed in a good location would help, like a EAW JF60 type. I don't care much for DSP's but I may have to use it here. There is a music instrument store a few doors away that may have the Mackie system. We could put it in for a trial and add sound absorption as required.
Thank you for the solid advice.

I would imagine that there will be some high frequency loss having them behind the screen. Maybe the slim profile will all ow them to be placed on the sides of the screen and pointed inwards just a bit? This would help keep some immediate reflections off of the walls.
If there are "fill" speakers anywhere then you will want to properly delay them to line up with the main L-R. Otherwise you will have a mess. If you do use these Mackie speakers, I recommend getting them as high up as possible and point them down just a bit so the top covers the back of the room. Where they are aimed will have drastic effects on the sound quality in the room.

 

[EJ3]

Our local theater is looking to upgrade its audio system. The room is 84' X 18' X 12' high, a shoe box shaped room, not classic theater shape. A drawing is attached.

Right now the room sounds pretty bad.View attachment 472560

Behind the screen there is speakers, Left. Right, Center, Sub. There are 6 surround speakers on the side walls.

The side walls and rear wall are drywall, covered with indoor outdoor low shag floor covering. The floor is epoxy covered concrete.

A Dolby CP750 Digital Cinema Processor is used to feed 2 Crown XLS2000 power amps.



I am asking the team here for recommendations to improve this theater.

My thoughts are to add more sound absorption material to wall and perhaps the untreated ceiling to start with.

They can keep the Dolby and amps. The owner is asking for a JBL system but the cost maybe too much.

We would like to improve the intelligibility of the sound.

The surround sound is horrible, but the owner wants to keep it because, "that's what people expect".

This theater used to show fine art films but now it shows kids animation and action movies.

Can anyone make some suggestions that may improve this very odd shaped theater?

IMHO you are dead on with hitting the floor to ceiling bounce with (alternating) absorption (or/and) standing wave breaking up materials on the ceiling (anything to minimize the bounce from the ceiling to the floor. Some of the same type thing on the side walls (perhaps alternating materials along the wall in a zig-zag pattern so that no wall has the same material 180 degrees from it on the opposite side wall.
But, my opinions may be like flinging mud to see what sticks.