# Optimum room size for seating 10 people in "sweet spot"



## Lain (Jun 12, 2008)

Heh, still in the "dream stages" of this mind you.
Anyways, I am currently planning on constructing a dedicated building for home theater.
With a dedicated building comes the advantage of choosing the best room characteristics for home theater, be they shape, size, material, etc.

So... I want to fit 10 people in to a 7 channel field's "sweet spot"










Anyone have an idea of what room size would be required for this? Or a way to compute such information?

On a side note, has anyone experimented with inserting extra speakers in to a sound field; place a speaker between Side Left and Back Left, and route half of S Left's channel and half of B Left's channel to said speaker? 

Thanks for the advice.


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## thewire (Jun 28, 2007)

Lain said:


> Heh, still in the "dream stages" of this mind you.
> Anyways, I am currently planning on constructing a dedicated building for home theater.
> With a dedicated building comes the advantage of choosing the best room characteristics for home theater, be they shape, size, material, etc.
> 
> ...


You could use CARDA to predict where speaker placement would be located and with what materials will be in the room. Many pro acoustic designers use this as an estamation. There is actually no perfect software...yet. It is however in development.

For more than 7.1 channels you could contact tmh. That is Tom Holman's company. Expect to spend some $$ :spend:.

http://www.tmhlabs.com/research/research.html 

You might also talk to Andysu. :R

http://www.hometheatershack.com/for...15117-s-true-what-they-say-walls-do-move.html

I have not tried any fancy surround matrixing but I tried some additional tweeters between my center channel and left and right speakers. I also tried two left and right speakers and two surrounds in all locations. The bass with two left and right speakers was to difficult with the bass being to punchy, and the additonal tweeters was well...interesting.

Expect to maybe have at least a center channel high in the future.:dontknow:

Are you going to use dipoles are monopoles (other) for the surrrounds?


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## Lain (Jun 12, 2008)

thewire said:


> Are you going to use dipoles are monopoles (other) for the surrrounds?


Monopoles. Despite the ravings about dipoles/bipoles for surround use, I would like to stick to the standard.

Hah I would not invest in over 7.1 if it required special services or expensive specialized equipment.

For the speaker config, I was thinking about building three Statement (Holtz's design) towers for the L R C, four Mini-Statements for the surrounds, and if I found a way to add speakers between the standard channels, I would build some Monitor-Statements for that purpose. And at least one IB manifold in the front of the room (6 AE-IB15 in such a case), and possibly another at the back (4 AE-IB15 for both in that case) for LFE and x>40hz.

As far as placement goes I really want to keep to the speaker layout as close to ITU-R .775 as possible.

What is CARDA btw? I googled but found no software by that name.

*EDIT*

This diagram should provide an appropriate guide to my thoughts on the matter of splitting channels for "in-between-speakers":










The signal splitter is a Whirlwind 12 channel passive splitter. Used Balanced input/outputs: http://www.whirlwindusa.com/split.html#lbs

The mixer is the piece that needs to be located. I was thinking of using a Wendt NGS X2 ( http://www.wendtinc.net/x2inst.htm ) but on further reading of the directions I do not think it will work for my needs.


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## thewire (Jun 28, 2007)

I'm sorry I mispelled the software name. That was before my morning coffee. It is correctly spelled CARA. There is also RPG room optimizer suite and Ulysses.

www.cara.de

http://www.rpginc.com/products/roomoptizer/index.htm

www.ibfsoft.de/

I don't see anything wrong with having some additional surrounds if they were monopole. There are some places I have heard of that can do up to 10.2 channels, but these are dedicated to their own mixing or remixing.

What you are asking is how to take a track that was mixed in a 5.1 or 7.1 enviornment and translate that to a much larger one. If there was a decoding and proper way to implement this it would be done in the mastering stage. What you will be looking at is a way to demux each channel then remix that, but there is no standard to do so that I am aware of. I would look into building some kind of HTPC or pair of HTPC to handle some mulitchannel playback so complex.


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## Lain (Jun 12, 2008)

thewire said:


> What you are asking is how to take a track that was mixed in a 5.1 or 7.1 enviornment and translate that to a much larger one.


This is the gist yes. Basically, I want to fill in the "gaps" between the speakers, so that the sound stage is very robust. Sound stage reinforcement I guess you could call it.



thewire said:


> If there was a decoding and proper way to implement this it would be done in the mastering stage. What you will be looking at is a way to demux each channel then remix that, but there is no standard to do so that I am aware of. I would look into building some kind of HTPC or pair of HTPC to handle some mulitchannel playback so complex.


Hah yeah I would have to re-mix every movie that I wanted to watch too.

I am pretty sure for my task that a simple mixing of two channels to produce an "in-between" will be adequate.


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## thewire (Jun 28, 2007)

I would consider some way to do adaptive decorrelation to each channel so that the sound does not collapse in a mono signal between each channel. Running each pair in and out phase, then adding some kind of difference in each delay may work. There are movie modes etc that I think you could apply to one signal for ambiance, then run the next descrete. This is my theory of how it might work but I am interested in what you come up with.


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