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the listening room: "golden ratio"?

I too am about to build a listening room, actually, I'm building a garage and adding the room over the top. There seems to be a lot of advice to pay attention to the "golden ratio" which, essentially requires a room at least 25 feet long, by, roughly 17. this seems really "BIG". The rationale for the size is based on the theory that the lower hz frequency has a "wave length" of 25' or something to that affect. However, there are few speakers that reach down to that range. I have BW N804, whose freq. response is around 40hz. I was thinking of getting some N803's which add a bit, but still nothing close to 20hz. As nice as it might be to build a 25'X 17' room, I'd like to stick to somehthing around 15 X 12, roughly half the total size of the garage. How much would I "lose" in that size? The other consideration is the cost of heating this room, living in the north, my electronics would not like to spend the winter out there at -30 and electric base board heat would run up a hell of a bill.
thoughts?
joeb
joeb
zargon's avatar
zargon
453 posts
 
Joeb,
You might consider opening the ceiling to the roof (cathedral). I have a second floor listening room over the garage that is 18'W x 28'D with 9' walls and a 13' peak. It is very close to the golden ratio. The extra height really opens up the sound stage vertically. I used the Cardas formulas for speaker placement from the side walls, but kept the speakers at 5' from the rear wall. The image is phenominally wide, deep and high and forward of the speakers. This room is one of the best I have heard.
joeb OP
121 posts
 
Zargon, Great Idea. I have already thrown out the previous dimensions, way too small, I am going with a L22 by W15. the only question is to go with a 8' or 10' ceiling. Probably the 10'. The previous question remains to be answered however, re: the frequency resonant mode dispersion. with a 10x15x21 there is a pretty good balance across the fr. span from say 25hz to 300 hz, but some bundling in the low mid and hi mid range. I still don't understand how much variance of frq. dispersion transalates to sound distortion. Does say a gap of 25hz next to a mode make a "BIG" difference? Or does it require a 40hz span? etc. If anyone was really interested I could post the exact figures.
thanks, Joeb
nar_com
70 posts
 
Golden ratio is :
Phi = 1.618033..
Phi*Phi = 2.618033..

That will give you with 8ft ceiling approximately

8'x13'x21'

However the I would go with higher ceilings if possible
joeb OP
121 posts
 
Nar, com, Now I'm really confused, I thought the ratio was:
1: 1.4: 1.9 where 1= height etc. And why, if 8x13x21 is the "gr" would you go with a higher ceiling?
joe
nar_com
70 posts
 
Joeb,

The golden ratio is the irrational number that is equal to (sqrt(5)+1)/2 = 1.618033989...
Just do search on the Net for GR and you will find more info than you need.

GR is only one of the ways to build the room and I’m sure rooms with other dimensions could sound wonderful. I’m not an acoustical expert and not pretending to be even close to one. If you are not sure what to do, you’d better consult someone who knows better or start reading books on acoustics.

As to higher ceilings I feel that it will give you more open sound plus I personally fill better in rooms with ceilings higher than 8ft.
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