# Definition of 5:3:2 or 2:3:5

Discussion in 'Beginners, General Questions' started by Geoff S, Jul 8, 2003.

1. ### Geoff S Well-Known Member

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I've heard these ratios used before but can't 100% interprut what they mean. I think it has to do with room size, in which the 5:3:2 is LxWxH of the room. Seems right to say for example a room with a 10ft cieling would be 15 feet wide and 25ft long by this ideal. Am I correct or way off?

2. ### Michael Reuben Well-Known Member

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I'm not aware of any formulas regarding room size for HT. It sounds like you may have heard someone refer to "2.35:1", which is a common aspect ratio for films. (Purists would point out that it's really 2.40:1, but the common lingo is "2.35".) In conversation, people often abbreviate this formula to "two three five".

The other common aspect ratio (or "AR") for U.S. films today is 1.85:1.

M.

3. ### Bob McElfresh Well-Known Member

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I think you are talking about the "Golden Cuboid" or "Golden Ratio" developed for music.

The goal was to determine what room dimensions would give the best sound.

They used wall-reflections as the 'problem' in that a wall X feet long would naturally reflect some frequencies better than others.

So a room that is 6 x 12 would be very bad because the 6 foot wall and the 12 ft wall would both reflect similar frequencies of sound giving an artifical boost to some.

A room with dimensions 5:3:2 is less-likely to have this type of boost.

This is usually only an issue for dedicated music/HT rooms. In a real-world living room there are doors, windows, furniture, etc., that break up the room into smaller sub-sections. There are also wall-treatments and equalization that can solve these problems.

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