Happy Accident


I've always read that the distance between the speakers should (more or less) equal the distance from each speaker to the listening chair. 

Our system is in the living room and due to furniture location, I'm guessing the  former distance has always been about 10% less than the latter (math is not my strong point).  Experimenting with toe-in has resulted in either a strong center image with a narrower sound-stage or vice versa. I've assumed the only way to improve matters would be to move my listening chair forward or the speakers further apart, neither of which is possible.  

But, as my wife will tell you, audio brings out my OCD tendencies. A couple days ago, I was once again messing around and tried toeing-in the speakers so their focus converged about 18 inches behind my head. This meant that the distance between speakers was, as always, 9 feet and the new distance between drivers and their point of convergence was 12 feet. 

As a result, the sound-stage now extends significantly beyond the speakers on each side without the center image collapsing. Actually, it's harder to detect a "center image", as the "image" spreads right across the sound-stage. The sound-stage is also deeper and resolution and bass actually seem to have improved. The point of convergence is only inches in front of a large, Craftsman style book-case with the typical "lattice" design of glass and oak. The speakers flank a slate hearth. 

Lacking the sort of experience/knowledge that might explain why "breaking the rules" has paid off to such an extent, this scenario falls into the category of "happy accident". I can only guess that it must have something to do with the room. 

Perhaps wiser individuals could offer a more scientific explanation... 

 

 

stuartk

@mijostyn 

"Women can not change the laws of physics. Well, maybe they can just not when it comes to audio".

🤣

Back in the days when I was listening critically (the 1980s and early ’90’s), I used a pair of 15 ohm Rogers LS3/5As. I had them sited upon a pair of bar stools and canted inward so that their axis was just in front of my listening area. Back in their heyday these speakers could image better than any conventional enclosure speaker I had ever heard. IMO, only the Quad ESL could image better.

Women can not change the laws of physics. Well, maybe they can just not when it comes to audio. There are some very pleasing absorption panels. Ask the wife to pick a motif. They love doing that. A digital preamp with room control is your best bet otherwise. 

I understand the view thing. We have huge picture windows in the kitchen where my wife spends most of her time (bird watching). My system is in a theater room which needs to be blacked out as much as possible. The room is painted a very dark blue. Putting a window there was the biggest mistake I made designing the house. I though black out blinds would handle it.....not. 

@wyoboy 

I have nothing against stumbling into something good!  

@mijostyn 

The system is in our living room. We have large windows but I have no desire to remove them as we live in a conifer forest and I enjoy the view too much. My wife would not welcome room treatments and I can't fault her for that. If the improvements I'm experiencing are due to sheer luck, that's OK. I have no complaints!  

@stuartk , There is no reason you should not be able to make your current situation work. Your seating will be further back in the hall, images will be smaller but that is all. 1st off the image should never extend beyond the speakers unless there are phasing tricks being used like in Roger Water's  Amused to Death. The effect of imaging beyond the speakers is due to poor control of early reflections off the side walls. Some sound absorption is in order. Point the speakers right at your head. The next problem that affects proper imaging is imbalance between the channels. Your brain locates noises by volume and phase. If the 2 channels do not have the exact same frequency response curves the image is smeared, out of focus as some frequencies are louder in one channel than the other. No two identical loudspeakers have exactly the same response curve. Then you really screw things up by putting them in different positions. Now each speaker sees a different acoustic picture. I demonstrated this to a friend just yesterday. He had heard my system and wondered why his could not create a similar image. I measure each channel and showed him the curves and in the midrange they were wildly different up to 10 dB apart in places!  The only way to contend with this is digital EQ where you can adjust each channel independently to match within a dB from 100 Hz to 10 kHz.  He is going to get a MiniDSP SHD digital preamp which can contend with this problem at a level he can afford, appropriate to his system. 

The speaker and room are parts of the same organ. There are some rooms you are never going to get a decent image in. Both speakers need to see identical but mirror image environments as a starting point. The more variation there is between speaker positions the more impossible things become. Windows in particular are a major problem. They resonate like drum heads at frequencies that vary depending on the size of the window and stiffness of the pane. I spent three grand having a window removed. What a breath of fresh air that was. 

In short, the best imaging requires symmetrical speaker environments with close tolerance loudspeakers, proper acoustic management and absorption at early/first reflection points along with digital signal processing to touch things up. Anything else is wishful thinking or shear luck. 

@stuartk I was surprised to read in Jim Smith's "Get Better Sound" book that he says he has often found that if the distance between speakers (tweeters) is roughly 83% of the distance to listening position that produces the best sound.  I guess he would know with all of his best in audio show awards and thousands of setups so i moved away from the equilateral triangle as you did and had the same "accident" (well, not accidental)!  Sounds like you stumbled on much the same thing although your measurement is to the point where the tweeter axes cross behind your head.  

@12many 

"... it really depends on the speaker and the room" 

  Yes!  

@antialiased 

I don't have the background to debate you on the basis of physics. All I can say is that others have found this not to be the case, me included. I trust my ears. 

@christianb5s4 

Some Wilson speakers provide a means of tilting the tweeters. I don't know the potential issues of tilting the entire cabinet. Someone more experienced may respond. 

@sgordon1 

Thanks -- good suggestion! 

@doni 

I'm glad you've found a way to compensate for that placement. 

@newbee 

Like me, you've found that experimentation can yield big rewards. 

I've found that having the speakers cross about three feet in front of my listening position to give the best results.  But, this is only true for my speakers (Audio Note and Klipsch CW4's) and if they are in the corners of the room and up against the walls.  

A laser can be an indispensable measuring tool.  Make sure both speakers are the same distance from side and rear walls (if this is feasible).  Toe in can be measured also.  Measure from both sides of the tops of speakers to the ceiling; how else do you know if your floor is level (or your ceiling is not!)  A test of your ability to discriminate: what is the smallest movement which produces a change in what you are hearing?

This is a great thread and learnings from everyone, part of the fun with this hobby is realizing how such small things can make a huge impact.

 

Question for anyone who has insight: what if the seating height makes it impossible for the tweeters to be at ear height? My speakers are a bit too tall versus the couch to accomplish this but I adjusted rake so the speakers point towards ear level. Is that the correct way to go about it?

@stuartk The equilateral triangle (positioning the stereo image) is still accurate as the ratio of the distance between you and the speaker sets the stage for good imaging.

It's the speaker toe-in (where the stereo image converges) afterwards completes and focuses the stage.

@antialiased 

I can't help but wonder how many music enthusiasts, having followed the conventional "equalteral triangle" wisdom, are (unknowingly) falling short of maximizing their listening enjoyment.

The mid-high frequencies are directional thus…

Typically pointing the tweeters so they converge 1-2 ft. behind your head is best for soundstage width and depth. The more convergence distance you add the more the staging begin to become unglued.

Converging too far in front and the stage narrows as you're physically introducing more stereo cross feed.

Converged right at the head and the treble can become a bit edgy and forward.

These have been my general observations tweaking the triangle for best stereo imaging.

Crazy right.  I sit further back from my speakers then the distance between them and have found the best soundstage when I don't have much toe in in the speaker.  Really depends on the speaker and room.  I was surprised how much a few changes will adjust the soundstage.  

The last time I repositioned my speakers I had a really big surprise, one that was counterintuitive. Previously I had my speakers about six feet from the wall behind them, about 9 ft apart and 10 1/2 feet from my 'ears'.  Toed in about 10 degrees. A little too airy but excellent overall imaging image. I'd been very happy with that set up for years (I've used this room for over 30 years now). Then one day I got bored :-)

I moved my speakers back to 4 ft off the wall, moved my 'ears' forward until I was about 10 ft from the speaker and pointed the speaker straight ahead. The net result was a very solid image latterly across the stage, side wall to side wall. Great upper bass/lower mid range integration with a bit of warmth. Only down side was a loss of tiny bit of depth of image.   Now my preferred placement of my speakers in this room. Whodaguessed!

@roxy54 

"Experimentation yields better results than formulas because of the many variables"

Clearly!   

I never saw the equilateral triangle as a hard and fast rule, and in fact it has never worked out best that way for me. Every speaker has its preferred distance from the front and side walls, and its ideal toe-in based on dispersion pattern and room size.

Experimentation yields better results than formulas because of the many variables.

@nonoise ​​@russ69 ​​@ghdprentice 

Thanks for your supportive comments. 

It's very gratifying to discover that, despite the limitations constraining my room, there are still ways to improve SQ and thus enhance the listening experience.

And I find it especially gratifying when such improvements don't involve opening the wallet. 

 

 

Congratulations! This is the way it is done… lots of experimentation.

 

The “rules” are always just starting positions. For my speakers the generality for toe in  is cross the beams 18” behind your head. In my room… no toe in and they disappear with a strong center image.

An equilateral loudspeaker positioning is just a good starting place. You should always try different positions and see what the effects are. No telling what is happening in your room without complex measurement and analysis but nothing wrong with using your ears as the final judge.

I went through the same thing as you when I got my new speakers. Before I had them, I always had the speakers aiming somewhere around the vicinity of my ears, give or take a few inches, but nothing more than that.

My new speakers seemed to have a larger lateral dispersion than what I’m used to so I experimented with them pointing straight out with no toe in and was surprised to hear a decent center image. Not the best I’ve heard, but decent.

Trying all manner of toe in, I settled on them aimed at where the palms of my hands would be if fully extended to the sides. Now I have a wonderfully wide center image that appears to adjust as I move to the side to show what’s beside/behind the performer as if viewing/listening from an angle, off center of an actual performance. Most uncanny.

I know a lot of it is psychoacoustics working it’s magic on me but a lot of it has to do with the high quality of the gear reproducing all those cues that make it possible.

All the best,
Nonoise