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Anotherspeaker placement question (distance measurements)

A couple of threads on this topic (one in this forum & another in, of all places, amps & preamps) have got me tweaking placement in my own small listening room.

I am getting that the recommendations for distance from speaker to rear wall are from the FRONT of the speaker to the rear wall, is that correct?

And as far as the recommendations to the side wall, is this from the outboard edge of the cabinet itself, OR from the center of the driver(s)?

I am assuming that listening position distance to the speaker is measured from tweeter to ear, NOT the shortest difference to the plane of speaker to speaker to the ear?

And yes, I do realize that it is not the recommended measurements that one should be concerned about, but how one’s speakers actually perform in one’s environment regardless of these measurements, but for the purposes of experimenting with some of the advice given in the two threads I have alluded to, proper interpretation will be helpful.

The distance that most concerns me, the one that I have the least flexibility to adjust per recommendations, is speaker-to-side-wall-distance. Meaning my speakers are too close to side boundaries. But my lateral sound stage is the best part of my system’s sound stage . . . it presents the illusion of being wider than the boundaries. Is lateral sound stage more a product of speaker-to-side-wall-distance? And if not, does speaker-to-side-wall distance have an effect on a specific aspect of the sound stage?

Thank you in advance for any & all input.

immatthewj
newbee
4,751 posts
 

You can reduce the sidewall distance (from the center of the driver to the wall) somewhat by deadening the surface of the wall adjacent to the speaker and slightly forward of the front of the speaker. This in combination with some sharp toe in helps a great deal. However the benefit is mainly in the mid's and high's. The mid bass is more difficult to control and depending on the distance to the side wall might well give you a mid/upper bass boost. Re toe in, I point the axis of my speakers to my corresponding ear. You can get excellent results by crossing the speakers axis in front of your head. 

All done by ear for enduring results, lots of speaker movements and it takes a long (!!!!!!) time to get your final results. Oh, BTW, measurement are made from the walls to the drivers, not the box. 

Have fun. :-)

immatthewj OP
1,081 posts
 

@newbee  , center of the driver then.  Thanks!

bigtwin's avatar
bigtwin
1,126 posts
 

@immatthewj   Hope this helps.

Focal, who know something about speakers, uses a flexible equation to find the best speaker placement.

“Optimisation For perfectionists, here is a formula for optimal positioning: If A is the distance from the centre of the woofer to the nearest floor or wall, B is the distance to the next closest floor or wall, and C is the greatest distance (A < B < C), the equation B2 = AC defines the ideal loudspeaker position. • Example: If the centre of the woofer is 20” (50cm) away from the rear wall (A) and 24” (60cm) above the floor (B), then the side wall will be ideally 28” (72cm) away [C = B2 ⁄ A = 28” 

I found this a little confusing at first, but it became clear in short order.  There are three distances involved.  Floor to center of woofer, Side Wall to center of woofer and rear wall to canter of woofer.  The shortest distance is always “A”.  This is usually floor to center which is the only constant.  The next shortest distance is always “B”, and the longest distance is always “C”.  The distance “C” is always (B x B) divided by A. 

By example, if your floor to woofer is 24 inches, and you are 30 inches from the side wall, you would need to be 37.5 inches off the rear wall.  Find the numbers that work for your space and see how you like the sound.  

In a nutshell, Focal suggests there is no rule about distance from any wall as long as C = (B x B) / A

knotscott
807 posts
 

There are some great calculations and theories for optimum placement available to us, but none of them address the variables that are unique to your room, so they aren't an absolute or one size fits all solution.  Use those theories and calculations as a starting point, but don't be afraid to experiment and find what's optimal for your room.  If it pleases you and works in your room, it not wrong. 😉

ozzy's avatar
ozzy
7,213 posts
 

I always use the center of the woofer.

That is; From side wall to center of the woofer and from the wall behind the speaker to the center of the woofer (at the front of the cabinet).

Same thing when measuring distance between speakers, from center to center of the woofers.

ozzy

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