Film-Tech Forum ARCHIVE: Auditorium dimensions

This is topic Auditorium dimensions in forum Ground Level at Film-Tech Forum ARCHIVE.

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Posted by Paul Sturtz (Member # 1079) on 07-17-2005, 04:24 PM:

I'm sure this isn't the first time someone's asked something similar to this, but....

We're about to carve out a two-screen theater out of an old Coca Cola bottling factory from 1937. We'll also be integrating a couple of other businesses in the building -- a bakery/cafe/bar and a video store. The goal is to get at least a 125-seat theater and a 60-seat theater for hold-overs (I know my size ambitions don't sound too grand but the building will be only around 7,000 sq. feet on the ground level even after we expand it 1,000 sq. feet with a tall ceiling for the big auditorium) I'll probably go for used seating with cupholders because we serve beer and wine, and will be serving food as well. The floor will be sloped.

1. What are the ideal dimensions (width, depth, height) for an auditorium? I've heard 1:1.55: 0.67 Is the ideal to have a rectangle that's not too narrow?

2. Also, what formula do you use for seats/sq. feet? I'm working with around 1 seat/15 sq. feet to allow for aisles, front of the theater, and generous row spacing.

Thanks, all -- you are a remarkably knowledgeable bunch. This is my first posting so be easy on me if I did something wrong.

Posted by Chase Hanson (Member # 2779) on 07-17-2005, 09:54 PM:

While this is probably not the answer that you are looking for...I would imagine that your answers to both those questions would be much more easily (and accurately) answered by your local Fire Marshall/Building Inspector. Your primary concern when planning should be compliance with local/county/state Building, Fire and Safety codes.

Just a thought of sorts.

Posted by Paul Sturtz (Member # 1079) on 07-17-2005, 10:18 PM:

Chase,
I appreciate the responsible words about compliance with the laws of my town (i.e. # of exits, thickness of fire walls etc.) but I'm already working on that with the help of an architect. I've come to this forum because I can configure the building in many ways, but the paramount goal is to have auditoriums that are really comfortable. Part of that is to design them with the optimum dimensions.

Hope this note finds you following all the rules of your municipality, and that you're staying out of trouble.

Posted by John Walsh (Member # 168) on 07-18-2005, 08:19 AM:

An architect is really the only person who can give you 'real' suggestions on how to divide up the space. This should be fairly easy, since he can just re-arrange things on a CAD system, and display the results. Sometimes, it's amazing anything can be made after getting everyone to agree on a design.

That said, you probably don't want auditorium dimensions that are exactly some multiple; ie, you don't want 50' wide by 100' long because there may be some wave issue causing reverberations. 1.55 seems too close to that. This problem can be reduced with sound deading material, but it's better not to create the problem in the first place. To have one side of the auditorium 'boxed out' for a closet or to fit in another room would make for uneven EQ problems. Tall ceilings mean bigger speakers and amps. When you and your architect have settled on a prelimnary layout, you might want to consult an acoustial engineer.

I've seen 38" to 42" back-to-back seat spacing, but can you afford to loose many seats?

Posted by Paul Sturtz (Member # 1079) on 07-18-2005, 08:48 AM:

That's a good reminder that I don't want to make the theater more tall than needed because of the sound issues.

Right now, I've got the big theater pegged to be around 38 feet wide by 50 feet deep (22-24 foot ceilings) and the smaller one at 25 feet wide by 37 feet deep (14 foot ceilings). I'm just trying to get at whether these kind of ratios are anywhere near the optimum for viewing. For instance, would it be better to get them to be boxier or to make it skinnier?

Has anyone worked with a ratio calculator for designing theaters from scratch?

Posted by John Pytlak (Member # 331) on 07-18-2005, 09:48 AM:

As a guideline, standard SMPTE 196M specifies the following for review rooms:

quote:
9 Review room viewing conditions
All observers in a review room shall be located within a standard observing area which shall be:
a) within the limits of a 15° angle on either side of a perpendicular to the center of the screen, in both the
horizontal and vertical planes; and
b) at a distance of 3 picture heights ± 1 picture height from the screen.

Most theatres have seats closer and further from the screen as well, so figure most of your seats will be between 1 and 5 times the height of the screen from the screen.

Posted by Paul Sturtz (Member # 1079) on 07-18-2005, 01:25 PM:

That's a very helpful formula, John. Thank you.