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

@immatthewj  Correct.  The shorest distance can be any of the three.  I think normally there is a Bass driver on the bottom and therefore that would most often be the shortest of the three.  Use the formula and the speakers can be in a variety of positions.  In the end, it's how they sound to you.  Cheers.

  @bigtwin  , (I will make a correction & report that my woofer is about 33.75 & the formula with the variations I was calculating with was giving me numbers very close to that) math was never a strong subject for me (I think that is why I have such troubles with electrical theory) but I sat down with a pen, paper & a calculater (I am still living in the 20th century) & went to work with my constant which, using the formula you provided, had to become C.  (I did say that this room hsa small amount of clean space to work with)  I started experimenting with BxB which is the dimension I feel I have the least flexibility with (side-wall-to-speaker x side-wall-to-speaker) and found a B that would work in my space and then I started adding inches and 1/2 inches to B and calculated 6 speaker placements that will fit in my allotted space. 

I am going to start with the numbers for the formula that will put the speakers 27" from the rear wall & go from there being fully cognizant that this formula is not etched in stone & if I cannot make it work, all I am out is my time & if I do discover the lost chord . . . hey, far out, man!

BUT:

the formula does not make any recommendations for listener's distance (I suppose ear to tweeter is what I should be measuring?) and I have been living with the preconceived notion of an equilateral triangle.  Is that where you would put your chair (to start) if you were using this formula to place speakers?

 

@immatthewj  I start with the triangle rule and kerp in mind it's not the law.  Many suggest trying to keep the distance between speakers not less than 75% of the distance to your chair. Once I have my chair set, I will stand behind the speaker and aim them to focus just behind my head.  Once again, it's what works for you.  All these rules are only guidance to help each room and system give max enjoyment.  Have fun with it.  

@bigtwin , mid range/woofer driver distance was a typo: 32.75 not 33.75.

Last night, after I finished typing, I got back in The Room & did some repositioning (but no listening as of yet).

                                   One thing I did determine, if I’ve got it correctly, with mid range/woofer driver distance being ’dimension C’ moving speaker out from rear wall means speakers also need to move in from side wall in order for the formula of: (BxB) divided by A = C (since in my case C, woofer/midrange distance is a fixed dimension).

So what that means (in a small area such as mine) is: limitations are placed on how far the speaker can move off the rear wall as when the speakers correspondingly move in from the sidewalls they get closer together. I would think that being too close together could not be lateral soundstage friendly(?) but I guess there is one way to find out.

My back wall is clean, meaning that there is nothing between the speakers and the wall.

What I am calling my sidewalls are not really walls, I should probably start referring to them as side boundaries, and that, unfortunately is not an option to play with, other than doing a 90 degree relocation with the speakers. The left boundary (I have been calling a wall for measurement purposes) is a gun safe and a file cabinet, this boundary is an even flat plane, about 5’ high (higher than the speakers) and doubles as my equipment rack. (Therefore, my electronics are all off to the left side and not between or behind the speakers.)

The right boundary which I have been referring to as a wall for the purposes of measurements is a relatively flat/even plane made up of a file cabinet (again about 5’ high) and book case with books and CDs going to the ceiling. (The wall behind the listening position is book case going to the ceiling.)

I am fully cognizant that this is way less than ideal, but in the past I have been able to reproduce a lateral soundstage that exceeds the boundaries, and plenty of height. Front to back has been filled, but I never got as much placement of detail from fore to aft as I do side to side.

I have recently been using about four well mastered.mixed SACDs for evaluating; they all have revealing imaging in various locations going on.

 

"I ain’t ever satisfied," Steve Earle wrote a song by that title.

@bigtwin , with the adjustable dimensions from the formula that I used to achieve 32.75 (or quite close) I did some listening. These dimensions put my speakers closer to the rear wall and further from the side boundaries,and since being further from the side boundaries moved them closer together, I had to move my listening position in significantly which, needless to say, increased the space between me and the book shelf covering the back wall.

"Comparisons are odious." I don’t know about that, but I hate doing them. It seems like when I try, I am never positive about what I heard the last time that I am attempting to compare to.

Anyway, what I feel that I might have noted (how’s that for being definitive?) is that the lateral sound stage is not as dramatic now; it still extends beyond the the speakers, but it doesn’t seem like (maybe) it is as far beyond the speakers. I always did & still do have great center imaging. However, I do think that (maybe) I am hearing more of a fullness from the forward plane of my soundstage to the back of my sound stage. However, the imaging within fore to aft is not as precise & revealing as from left to right & it never was. I don’t feel that height of the sound stage was affected, or if so, not by much.

One thing for sure, I previously made some comments about needing to turn off the lights & close my eyes or it was like sticking a pin in the balloon of my soundstage, and now with the speakers closer together & me even closer to them it is twice as true.

I am thinking that it would be the speaker placement from the side boundaries that would affect the lateral soundstage the most?

Next time I evaluate I’ll tweak only that dimension a bit and see what happens.. Like maybe an inch. I am also thinking I’ll hang some wool blankets on the side boundaries and if that is an improvement I will seriously start considering some type of room treatment beyond that. I have been playing the same three SACDs every time I do this, and I’d kind of like to listen to something else, but I am afraid that would really screw up my ability to compare.