Golden Ratio Question

[Youthman]

I was reading the Feb 2008 edition of Home Theater Magazine. On page 85 it discusses speaker placement and begins to discuss the "Golden Ratio". Here is what it says:

Multiply the width of the room by 0.447. This is the ideal distance from the speakers to the front wall. In a 12-foot-wide room, place the speakers 5 feet, 4.5 inches from the front wall.

Multiply the width of the room by 0.276. This is the ideal distance from the speakers to each side wall. If your room is 12 feet wide, place the speakers 3 feet, 4 inches from the side walls.

If this info is correct, since the width of my room is 13 feet, I would need to place my RF-83's 5.8 feet from the front wall and 3.6 feet from the side walls. That might be "Golden" but it is definitely impractical. Does anyone use this Golden Rule in their setup?

[lakedmb]

First time I have heard of this......

Aren't you suppose to make an equilateral triangle out of the front speakers and the main listening position? Distance between the main speakers is the same as the listener is to each of them.

If that is true and the "golden rule" is, then in the example you used the listener would be sitting roughly 5 ft. 4 inches from the speakers..... Seems pretty close to me.

[DrWho]

The problem I have with all the golden ratio solutions is that they never address performance characteristics. Instead, they focus on procedures "justified" with mysticism.

That's not to say that a golden ratio solution couldn't result in a good sound, but I would propose that alternate solutions can have the same sonic performance if they satisfy the same performance characteristics.

Or from another perspective, knowledge of what constitutes good performance should dictate the appropriate solution. As such, I would argue that even better performance can be achieved.

[Youthman]

Yes, I thought it was rather strange myself. I think I'm just going to play around with placement and see what sounds best to me because that's all that matters right? LOL.

[IndyKlipschFan]

contact Colterphoto1 on this one..

[artto]

The person who wrote that article is grossly misinformed.

The “Golden Ratio” or “Golden Mean” as it is often called, in the context of acoustical application, has to do with the room’s resonant modes that are a function of the room’s proportions ~ and only up to a certain point in size, after which it has no application at all.

While a speaker can be designed that is capable of exciting any and all room modes to the maximum extent possible (ala Khorn), simply changing the location of the speaker does not change the room modes because it has not changed the boundaries of the room. Changing a speaker’s location will however change the “sound of the speaker” just as adding/subtracting/moving furniture or people around the room will do. Changing the speaker’s location may slightly change how the speaker interacts with the room’s boundaries but it will NOT change the room modes.

The author has mistakenly taken an “idea” and misapplied the concept which shows a complete ineptness for the math behind it.

[mmiles]

There is a rule, not sure if it is golden or not, regarding room size.

Width x 1.618 = depth

Width / 1.618 = ceiling height

16" wide room = 26' deep, 10' ceiling

[colterphoto1]

Artto nailed it. That article is very misguided.

Colter's general rules of speaker placement. (these are my rules, that I have come up with through much experience and experimentation).

Unless using an acoustically transparent projection screen, place the mains .5x the screen width away from the screen, this gives a slightly wider sound stage than the viewing screen, and gets you closer to the equilateral triangle suggested for stereo listening. Tweeter horn center should be within the vertical center third of the screen.

Front main speakers should be distanced from the front wall the sum of the diameter of any rear mounted ports/passive radiators- as a starting point.

Center speaker should be horizontally centered with screen, immediately below or above the screen. Above the screen is preferred if there are multiple rows of seating, so that every viewer has unobstructed line from center speaker to head.

THX rules state to sit 1.728x the screen width away from the screen. This is to obtain a 40 degree viewing angle.

First set of surround should be on the sides and be WDST type speakers. Side surround 1-2 feet above and behind the height of your head when seated. If sitting against the rear wall, you may place the speakers at the front edge of seats, but still above you. But at least scoot the sofa out a foot or two to avoid the build-up of bass against walls.

Rear surround speakers either direct radiating rear center, smack up against each other (per THX rules), or if WDST type speakers, divide the rear wall into thirds and place speakers at that location, same height as side surrounds.

Do not attempt to 'aim' WDST speakers by using swivel brackets. There is no point. Remember that our ears are far more perceptive of sound sources in front than to the rear. All you need to know to give you surround clues is that 'that sound came from back there somewhere'- that's enough.

EXPERIMENT- all rooms are different, both acoustically and aethetically. People will assign different weights to each, so try some stuff out and and see what you like.

Michael

[Youthman]

Thx for the great insight Colter! I really appreciate you sharing your years of experience with us. You are a valuable asset to the forums.

[picky]

Fud's first Law of opposition: "If you push something hard enough, it WILL fall over!" []

Thanks to Firesign Theatre for that one. LOL