Question regarding room shape proposal - AVS Forum
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post #1 of 6 Old 01-11-2012, 06:35 AM - Thread Starter
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HI All !

I will be building a HT later this year once our home is completed. The HT will be located under a 20'x30' portion of a garage (ceiling will be 10'). The ceiling will be SpanCrete and ~ 90% of the walls will be concrete behind the 2x6 framing.

My question is this :

Would there be any benefit of designing the room like an Isosceles trapezoid vs. a rectangle where the front wall would be roughly 19' wide and the rear wall would be roughly 17-18' wide ?

Thanks!

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post #2 of 6 Old 01-11-2012, 07:29 AM
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Quote:
Originally Posted by rms8 View Post

Would there be any benefit of designing the room like an Isosceles trapezoid vs. a rectangle where the front wall would be roughly 19' wide and the rear wall would be roughly 17-18' wide ?

Sounds like a great space. There are benefits to not using a rectangle, but I'm not sure the angle from a 19' wall to a 17 or 18' wall is enough. I think you would need to come in a fair amount more than that. I recall a discussion with Bryan Pape, who is an acoustics genius, that the angle needs to be much higher than what most folks have in mind. A room with a 17 foot back wall would need to be roughly 13 feet at the opposite wall to get the desired result. I'd estimate then that with a 19 foot wall, you will need the opposite wall to be around 14.5'.

I'd suggest you seek out a guy like Bryan (bpape here on the forum) who has the acoustic expertise to properly calculate the math and give you the best answer.

I look forward to seeing the progress and pics. Great to have another IL build underway! We are thinking of having a meet, check out the Chicago thread in the meets section.
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post #3 of 6 Old 01-11-2012, 09:35 AM
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The other aspect to consider is that anything other than a rectangle becomes far more complex to predict. You will increase the number of modes in the room significantly, which will result in more problematic placement issues. Further, envelopment due to speaker placement and design will also become an issue. Plus, you just lose valuable space. I know Dennis Erskine has dealt with rooms in the past with that type of design, and has dealt with it in a pretty ingenius way.

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post #4 of 6 Old 01-11-2012, 09:52 AM
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A rectangle with dimensions that are exact multiples of each other e.g. 10x20x30 is a problematic starting point. Even if the room is kept rectangular you might want to modify the dimensions a little. The advice I got early on was to shorten my room to avoid this condition and to use the extra space to build an IB sub. I'm glad I did..

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post #5 of 6 Old 01-11-2012, 12:49 PM
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Quote:
Originally Posted by Moggie View Post

A rectangle with dimensions that are exact multiples of each other e.g. 10x20x30 is a problematic starting point. Even if the room is kept rectangular you might want to modify the dimensions a little. The advice I got early on was to shorten my room to avoid this condition and to use the extra space to build an IB sub. I'm glad I did..

Actually, I would argue against shaving space. Space in a theater is THE most valuable element within the theater. I have many methods and tools to deal with low frequency issues, but I have nothing available to me to create additional space. Never give up space if it can be helped.

Shawn Byrne
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Design-Video & Audio Calibration Information

The original Pro Theater Layout
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post #6 of 6 Old 01-12-2012, 05:53 AM - Thread Starter
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Quote:
Originally Posted by SierraMikeBravo View Post

Actually, I would argue against shaving space. Space in a theater is THE most valuable element within the theater. I have many methods and tools to deal with low frequency issues, but I have nothing available to me to create additional space. Never give up space if it can be helped.


Thanks for all the comments!

I'll just keep the dimensions to get as much sqft'age as I can. Thanks Shawn!

See the Supercharged 10second II here :
http://www.cardomain.com/ride/3131345
See the ConcreteBunker Build w/8x18" IB subs here:

http://www.avsforum.com/t/1445270/27l-x-22w-x-10h-diy-concrete-bunker-w-eight-18-ib-subs/0_70

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