Toe In - Crossing In Front of the Listening Position

[Rob S.]

Boy,  you guys got me thinkin' about my speaker placement.   Carl, why not bring some of that fancy laser equipment to WV (we don't have that here)   and help me get mine setup?   I will make it worth your while.  We do have good food, good beer, good accomodations...... Bring that smart guy Rich too.

I suspect I'm fairly close to optimal- but I wouldn't be surprised if you move my speakers a foot in any direction.   And you talk of 1mm increments?  Shoot I'm not even close yet. 

Rob S.

[shep]

We are truly mad!

[Face]

Tannoy recommended this type of placement with their HPD drivers back in the early 80's. 

[tmazz]

All of this talk about room centers and measurements and laser alignments is all well and good and may give you a decent starting point, the only practical way to determine the final positions is by ear using trial and error. Placing your speakers to a measured center point in the room would only work if the room was empty or everything else in the room was place symmetrically. However this is never the case. Many of us have listening spaces that are irregular in shape. And even those who have a square or rectangular room have furnature and equipment that make the acoustic properties of one side of the room different that that of the other side. While measurements can give me a good starting place, I always use my ears as the final placement tool. I start of using test tones like the in-phase/out of phase track on the Stereophile test CD to get a closer sense of placement and toe-in angle and then do my final fine tuning with some actual music form a well recorded source that provides good spacial imaging cues. Moving a speaker as little as 1/4 inch can have a dramatic effect on the sound. When I am done it is not the least bit unusual if the speakers not the same distance from the center line of the room or even the same distance from the listening position.While the distance away from the measured centers may only be inches or even fractions of an inch, the point is that the small postion changes can make a huge difference and we should always remember that we don't listen with rulers and lasers, we listen with our ears, so they are the best tools for optimizing our speaker placements.

Tom

[Carlman]

Hey Tom, great point and good advice.  Listen with your ears!

Keep in mind some people really do have completely symetrical rooms and furniture... which has also been measured to be within 1/4" of center... and all room acoustics are done in a specific way to accomodate the symetry... just sayin'.

[Bob in St. Louis]

All depends on your particular level of anal retentivity. 

Bob

[tmazz]

Carlman,

That is a really amazing situation to be able to design in total symmetry from both a room design and a furnishing standpoint. But, most of us have to work around asymmetrical acoustics as even those of us who are lucky enough to have a dedicated audio room got it by taking over an existing space, which was not designed with acoustic symmetry as its top priority. So for the vast majority of us who have to deal with things like less than acoustically perfect room layouts and interior decorating by our wives (marital harmony is almost as important as musical harmony if we are to stay with this hobby over the long run), using your ears is still the best way to compensated for these issues. Using the measurements is a great place to start from, but the measurements and calculations would end up being ridiculously complex if they had to take in all of the acoustic imperfections that most of us have to deal with and try to compensate for. As always, the ears should be the final authority

Tom

PS - The guy with the perfect room must either be single or have an absolute saint for a wife!!

[rollo]

All of this talk about room centers and measurements and laser alignments is all well and good and may give you a decent starting point, the only practical way to determine the final positions is by ear using trial and error. Placing your speakers to a measured center point in the room would only work if the room was empty or everything else in the room was place symmetrically. However this is never the case. Many of us have listening spaces that are irregular in shape. And even those who have a square or rectangular room have furnature and equipment that make the acoustic properties of one side of the room different that that of the other side. While measurements can give me a good starting place, I always use my ears as the final placement tool. I start of using test tones like the in-phase/out of phase track on the Stereophile test CD to get a closer sense of placement and toe-in angle and then do my final fine tuning with some actual music form a well recorded source that provides good spacial imaging cues. Moving a speaker as little as 1/4 inch can have a dramatic effect on the sound. When I am done it is not the least bit unusual if the speakers not the same distance from the center line of the room or even the same distance from the listening position.While the distance away from the measured centers may only be inches or even fractions of an inch, the point is that the small postion changes can make a huge difference and we should always remember that we don't listen with rulers and lasers, we listen with our ears, so they are the best tools for optimizing our speaker placements.

Tom

Tom, The laser and measurements are the starting point. Either rule of thirds, the Cardas method , whatever. when all is said and done the old Sheffield test record where one can use the out of phase test to perfectly position your speakers. Adjust the position or toe in of one speaker only until the out of phasesignal sounds like its coming from ALL AROUND the ROOM. The best method I've ever used after positioning my speakers. Have fun trying.


charles

[allenzachary]

PS - The guy with the perfect room must either be single or have an absolute saint for a wife!!

Well, Carl's wife, Christine, is Catholic....

[mdconnelly]

PS - The guy with the perfect room must either be single or have an absolute saint for a wife!!

Well, Carl's wife, Christine, is Catholic....

A very supportive and saintly wife she is, but then, Carl has been banished to the basement where he and his perfect room reside.  On the other hand, that may just be part of what makes it perfect! 

[Carlman]

Oh, it's not all bad being 'banished'...   I'm pretty happy to be here... it's taken a long time and a lot of 'nervosa' to get what I have.  I'm thinking of having another G2G just to spin music.. vinyl or cd and have fun before Christmas is upon us.. Probably the weekend of the Dec 12/13th.. just thinking.

I wish I could get to see Rob S. sometime this year.. but it just may not be possible... which is truly regrettable.. but I will get up there.. and I'll bring my laser!

-C

[miniminim]

The entire point of crossing the axes at or slightly in front of the central listener is to reduce the "head in a vice" requirement for reasonable stereo effect. Any other typical arrangement creates a situation where, when the head (or the entire listener) is moved laterally the image immediately shifts towards the near side.

By "typical arrangement", I mean where the axes of the speakers fall somewhere between slightly behind the center listener's head through straight ahead to slightly toed out.

The thinking is that, as you move your head laterally towards one speaker and away from the far one, you are moving progressively off the axis of the near one as you move closer to it - the lowered level balancing the earlier sound arrival and to an extent canceling the "precedence effect". Conversely, of course, as you move in the same direction the idea is that you move onto the axis of the farther speaker, compensating for the increasing distance.

Naturally, this only works with directional speakers, so speakers possessing controlled directivity, such as Dr Geddes' Abbeys, Duke LeJeune's Audio Kinesis, Bob Smith's Timepieces and others with waveguides limiting the dispersion at the bottom end of the passband of the mid and HF drivers to match the disperison characteristics of the driver next lower in frequency, work best.

As usual, it's a juggling of trade-offs.

Adjustment of arrangement most easily made with correlated mono signal - pink noise is good, but any mono music signal will do. Adjust for tightest phantom image.

miniminim

[Carlman]

I agree, minimum... I've experienced this in my room:
I have mine toed in front of the 2nd row and behind the front row so I can get both effects.  I tend to like the front row best but occasionally it's nice to hear things on the 2nd row.. just different presentations.  I think the front row more accurately reproduces the image produced by the engineers.. but the 2nd row tends to make the imaging more like what I think it should be..
The detail and tone on front row is a little more 'present' to me on first row so that's where I usually sit. I am an imaging fanatic so I love it when the recording has it done right.
-C

[JLM]

I've settled on crossing just behind my head from "the" chair (room/setup ala Cardas), but frankly do most of my listening from the office chair that is about 5 feet behind so I've got roughly the same options as Carl.

But with large single driver speakers (and no silly whizzers) my issues are high frequency beaming, not what happens at a given crossover frequency.

[shep]

" All depends on your particular level of anal retentivity." That says it all. Quite frankly speaker placement is a super suck pain in the A. I hate it but there's no way round. A lot depends on the design of the speakers; how tolerant they are of the room. I'm lucky to have slim TL's that do excite room boundaries but even so it's a real problem to find the exact distances. I think this is several orders of magnitude more maddening than comparing cables. I'm glad no one can see me at one in the AM, bounding up from the sofa to move speakers a centimeter: the mixture of manic and despair, only to be repeated with the next cd. I think this is a good clinical definition of madness.