# Need help with FINAL room dimensions. Golden ratio??



## AutoDelphi (Jul 23, 2014)

Hello everyone, I would like to thank everyone for their input so far. You have all been so very helpful.

I am about to drywall my theater room, I keep reading about the golden ratio for sound quality. I am at the point that I am ready for drywall. 

My question is do I have the right length for the room? I have the opportunity to make the room longer or shorter if need. 

The room is 10' wide by 7.5' high by 16' long. I have the option to make it longer if needed but I have read allover the web that you want to build the room to the golden ratio.

The main listening position is 11'

My question is do I lengthen the room or leave it as be??? Any help would be great as I am looking for start dry walling it this weekend to have it ready for my sons birthday in 2 weeks. 

Thank you


----------



## Prof. (Oct 20, 2006)

I would leave it at that length..If you make it any longer you will start to get a "hallway" effect, which sets up some nasty resonances and they are not easy to control..


----------



## AutoDelphi (Jul 23, 2014)

Would you say I have the optimal length for the width I have to work with?


----------



## brwsaw (Feb 19, 2014)

Is this to be an HT or audio only room? Just curious, it would help me choose.
One of my regrets is that I didn't place my electronics outside of my room.
I had a similar decision to make about my rooms lenght.
Had I placed my equipment outside the back wall rather than against it I would have had room for a second row AND I wouldn't hear the fans as they kick in and out.
The golden ratios are guidelines, but using them has proven to be worth the effort.


----------



## AutoDelphi (Jul 23, 2014)

brwsaw said:


> Is this to be an HT or audio only room? Just curious, it would help me choose.
> One of my regrets is that I didn't place my electronics outside of my room.
> I had a similar decision to make about my rooms length.
> Had I placed my equipment outside the back wall rather than against it I would have had room for a second row AND I wouldn't hear the fans as they kick in and out.
> The golden ratios are guidelines, but using them has proven to be worth the effort.




I have my electronics in another room, my receiver is a cabinet built into the wall. Amp fans and other noise are not an issue. 

The room is 30% Listening and 70% Home Theater. 

Do I have a overall consensus that my room size should be where its at??


----------



## brwsaw (Feb 19, 2014)

We've had quite a few small rooms before and almost always wanted more depth.
Golden ratios will drive you mad.
I'd consider the 17.45' dimension.


----------



## Prof. (Oct 20, 2006)

AutoDelphi said:


> I have my electronics in another room, my receiver is a cabinet built into the wall. Amp fans and other noise are not an issue.
> 
> The room is 30% Listening and 70% Home Theater.
> 
> Do I have a overall consensus that my room size should be where its at??


If you plan to put in a screen wall, then you're going to lose about 2'6" from the length of the room, in which case you could make the room a little longer..


----------



## Tonto (Jun 30, 2007)

Speaker placement is the key to getting the best sound. Generaly the speakers need to be away form the wall to sound their best. So I'm agreeing with the professor. Make the room as long as possible, position the speakers for optimum sound, then build the acoustically transparent screen wall in front of them.


----------



## Philip Nel (Apr 23, 2014)

Hi 

There are three Sepmeyer golden room ratio's

Room A: C x 1.14C x 1.39C (Ceiling height(C) x Room width x Room Length)

Room B: C x 1.28C x 1.54C (Ceiling height(C) x Room width x Room Length)

Room C: C x 1.60C x 2.33C (Ceiling height(C) x Room width x Room Length)

So for your room with a ceiling height of 7.5' your are looking at the following possibilities 

Room A: 7.5' x 8.55' x 10.42'

Room B: 7.5' x 9.6' x 11.55'

Room C: 7.5' x 12' x 17.47'

Looks like you are close to Room c with current dimensions. So If you can make it a Foot and a Half longer and 2 feet wider bobs your uncle. 

That is of course if you are hell bent on sticking to Golden ratio.

http://www.cinemasource.com/articles/room_modes/modes.html (The source to above information)


----------



## robbo266317 (Sep 22, 2008)

The only issue with the current room is that the length of 16' is close to 2xheight (7.5x2 = 15)
If you can go 1' wider and 1.3'longer then you would be slightly better off.
If you can't go wider then still try to go ~1' longer.

A useful tool is http://www.bobgolds.com/Mode/RoomModes.htm and look at the results section at the bottom. 
so for 11 x 7.5 x 17 the results are:-

Computed Information:
Room Dimensions: Length=17 ft, Width=11 ft, Height=7.5 ft
Room Ratio: 1 : 1.46 : 2.26
R. Walker BBC 1996:
- 1.1w / h < l / h < ((4.5w / h) - 4): Pass
- l < 3h & w < 3h: Pass
- no integer multiple within 5%: Pass
Nearest Known Ratio:- "18) Dolby's optimum ratios for Film & Music Room" 1 : 1.493 : 2.313


----------



## AutoDelphi (Jul 23, 2014)

> A useful tool is http://www.bobgolds.com/Mode/RoomModes.htm and look at the results section at the bottom.
> so for 11 x 7.5 x 17 the results are:-
> 
> Computed Information:
> ...


Thank you for the link to the room calculator. What does the following information represent? 

RT60 (ITU/EBU Control Room Recommended): 184 ms
- ±50ms from 200Hz to 4kHz = 134 to 234ms
- <+300ms at 63hz = 484ms
- 200<RT60<400ms

and

Absorbtion to achieve ITU RT60: 376 sabins


I am going to take measurements down to the inch and see what numbers the room calculator comes up with?


----------



## Babak (Mar 20, 2009)

Hi 

There had been extensive studies on room dimensions by Bolt and others 

For example 
http://www.acoustics.salford.ac.uk/acoustics_info/room_sizing/?content=methods


A calculator 
http://www.acoustic.ua/forms/rr.en.html

Do some research on that, there is plenty in the web.

Cheers
Babak


----------

