speaker placement & viewing distance (1 Viewer)

[Jeffrey Chin]

1. http://www.linkwitzlab.com/rooms.htm
Re: modes1.xls spreadsheet on that page:
Can someone help interpret how to translate those figures on the spreadsheet to help w/ speaker placement?
--------------------------------------------
2. According to Dolby Labs, re: SPEAKER PLACEMENT:
Placing the left and right speakers to form a 45 degree angle with your favorite viewing position will duplicate the soundtrack mixer's perspective.
Example:
This means (using 45 degree angles), . . .your optimum "sweet spot" sitting distance would be 9 ft. 7-7/8 inches away, if your front speakers are 8 ft. apart. (8 ft. 5-3/8 inches away for 7 ft. apart)
I have my Maggies toed in at 45 degrees. Nice sweet spot.
According to Dolby,
7 : 8.5 = spkr dist : viewing dist ratio
----------------------------------------------
3. A post from another forum suggests:
Perhaps this will help #1=Distance from the front wall: measure the height of your ceiling(inches)and multiply that fiqure by 0.618 that should be your distance from
the front wall... as for the side walls:measure the width of your room in inches and divide by 18 Next,multiply that by 5. That will give a good distance from the side walls.Electrostatic speakers do like to be on a tilt upward in the front of the speaker Toe in is very ,very important with these speakers
So that means if I had a 15' ceiling, the distance from the front wall should be 111" ? WTF?
------------------------------------------------
4. http://www.tweakshop.com/Speaker%20Placement.html
This link suggests 2-3ft from the walls & suggests symmetrical distances
side wall distance = front wall distance
--------------------------------------------------
5. TV VIEWING DISTANCE:
http://www.theperfectvision.com/howto/howto_tech_4.htm
So for my 36" Sony Wega, it should be 2.5x picture height?
-------------------------------------------------
Comments appreciated
Please refer to #1, #2, #3, #4, #5 when replying.
------------------
Link Removed
[Edited last by Jeffrey Chin on July 19, 2001 at 10:46 AM]

 

[Bob McElfresh]

Jeffrey: First let me thank you for all the great links. I will bookmark most of them.
Now to your questions:
#1 - You cannot use the room-modes spreadsheet or calculations to help you place your speakers. This is trying to tell you what frequencies your ROOM will have problems with. (And note: these issues usually apply only to dedicated listening/HT rooms, not living rooms).
#2 - Exactly 45 degrees from the listening position: Well.... I feel this is a good starting point, but not a hard & fast rule. I think it is more important to pull the speakers into the room than to get an exact 45 degree angle. The ammount of toe-in you use can get you the same effect even with a different angle, and the horizontal-throw pattern of your speakers will have another effect.
And this brings up another issue: Why are you trying to exactly match the soundtrack mixers system? Where did someone decide that duplicating a production booth is the ultimate goal of speaker placement?
The sound engineers/mixers DO NOT LISTEN TO THEIR SYSTEMS FOR ENJOYMENT! Their systems are often optimized to listen for defects, not accuracy/impact/pleasure.
#4 - Equal side-wall distance and back-wall distance for speakers: this is something of a third-order adjustment. You have to have lots of other things adjusted & fixed before this one would make a difference.
But yes, if you could do this, it could improve the spaciousness of the sound. (But if you really want this, buy a bipole speaker that is designed to bounce sound off of the rear-walls).

 

[Kevin C Brown]

I've actually never tried any of these, because maybe I accidentally ended up with a setup that works well enough.
But the best one that I've heard, that is supposed to work more or less universally, is to divide your room into 3rds in both directions.
The front speakers go 1/3 the distance in from the front and side walls, and your listening position is centered, 2/3 from the front wall.
That's for stereo. For home theater, I don't know!
Although I've also heard doing the same thing but by 5ths.
The front speakers 1/5 the distance in from the front and side walls. The rears the same but from the back. (And then maybe the listening position in the middle.)
But it is true that depending on the dimensions of the room, different frequencies will have problems at different locations.
I always liked the suggestion of not having any wall at a 90 degree angle from any other wall. But kind of hard in practice!
------------------