stubbed your toe in

[AJ Soundfield]

Interesting, my speakers have a similar offset, and out of curiosity, I've tried 'em both ways. Obviously the tweeter in position was as designed, and preferred.

The offset of the tweeter is to make it varied distances from the edges, which spreads out the diffraction signature over a wider band frequencies when measured from some distance on axis.
Here is a nice article http://www.linkwitzlab.com/diffraction.htm

cheers

AJ

 

[AJ Soundfield]

Some find they get a wider sound stage with less or no toe in.

That's because ASW depends on lateral reflections.

 

[NorthSky]

That's recommended for most so called CD (Constant Directivity) speakers, like horns-waveguides, etc.. The reason isn't to complex if one understands how stereo constructs are created via time/intensity. Here is a nice illustration:

Due to the L-R intensities remaining consistent due to the directivity and prop loss over distance, the image is stable over a wide listen area and does change with head movement.

cheers

AJ

Hi AJ, that's ↑ J. Gordon Holt's preferred setup. ...The two speakers crossing in front of him by about three-four feet or so, or right in the middle of the room between the two speakers and the listener.

Funny thing is this; I know nobody who has his two speakers set that way, nobody. I think the people I know are not all audiophiles.

__________

♦ http://integracoustics.com/MUG/MUG/reviews/stereophile_monolith.htm

Imaging
"One thing that remained consistently superb throughout the testing was the Monoliths' imaging. To hear electrostatic-type detail, smoothness, and attack, without the usual on-axis sizzle and off-axis dullness and imaging deterioration, was a rare privilege. What this means in terms of stereo imaging has to be experienced to be believed! The Monoliths image almost as well as any system I have ever heard, and is even capable of the remarkable holographic effects I have previously heard only from a couple of satellite systems. (By "holographic" I refer to the impression that closely miked sounds are located out in front of the speakers, floating spookily in space a few apparent feet in front of my face.) The soundstage is wide and deep, and front-to-back perspectives replicate those of the recordings themselves about as well as I have heard from any speaker system.

Interestingly, though, while the Monolith has no high-end directivity, it does have some in the middle range. To either side of the speaker's "axis" the sound loses some of its body and impact, and if the speakers are not toed-in towards the center of the listening area there is a significant shift in lateral image position as one moves from side to side. There are speakers which provide more uniform lateral localization from a wider listening area, but all of these have a "shaped" directivity pattern in which the apparent output from each driver diminishes as you approach a location directly in front of it. (The dbx "Soundfield" speaker is a prime example of this directivity shaping.) But, all in all, the imaging from the Monoliths is as good as I have heard from any other kind of speaker, particularly any electrostatics."
__________

 

[AJ Soundfield]

Hi AJ, that's ↑ J. Gordon Holt's preferred setup. ...The two speakers crossing in front of him by about three-four feet or so, or right in the middle of the room between the two speakers and the listener.

Hi Bob,
What is actually shown is more like what Sal described: Equilateral triangle, direct axis crossing in front of listener...but more like 3", not 3-4 feet. The text of the picture contains the info.

cheers,

AJ

 

[Fitzcaraldo215]

I do not think the speaker toe in issue concept is complicated at all. It is not about just the speaker, so there is no universal answer to what is best, like aim them X feet in front of you. Like most things that seem to be about speakers, this is actually about an integrated, complex sound delivery system including the speaker, the room and your ears, including how distant and how reflective are the surfaces on the side walls, ceiling and floor. Surely, what you hear is the result of direct plus reflected sound, unless you are listening with headphones (ugh!) or in a near field situation, something I also do not particularly like or recommend, especially if your wife is sitting fight next to you.

So, while that is conceptually not difficult to understand, achieving a sound that pleases you in most respects comes down to trial and error, involving subjective assessments of the result until you "get it right" for that speaker, its unique dispersion characteristics and how your room reacts to that.

It is quite amazing how so many speaker reviewers have commented on optimizing toe in, as if it only depended on the speaker. Totally neglected in those reviews is the influence of their rooms on that "optimum".

 

[NorthSky]

Hi Bob,
What is actually shown is more like what Sal described: Equilateral triangle, direct axis crossing in front of listener...but more like 3", not 3-4 feet.
The text of the picture contains the info.

cheers,

AJ

Oh, sorry I went with the geometric design presented.

Cheers,

________

I did some research since you posted that "figure" and find some quotes (audio blog comments), from Ethan example, who said to aim the speakers directly @ the listeners ears, where speakers generally sound their best. Of course I disagree with Ethan's perspective, because not all speakers sound their best directly on-axis with our ears, certainly not mine because they are not perfect music reproducers but have a flaw in the 10-12kHz region, so they can become irritating with some music; vocals, violins, piano...if directly toe-in @ my ears.

The phantom image can vary too from the room, and the amount of toe-in or not.
The soundstage's width and depth too; and with some speakers in some rooms the amount of toe-in will more or less dictate the listener's own sound priorities...as to how he/she likes a holgraphic soundstage of this proportion or of that one.
It's like a live jazz band @ a jazz cabaret. Where you like to sit has many personal attributes that not everyone else share. The science of sounds distribution (music) in a comfortable dimensional zone of space and time is not everyone's scientific absolute, even if one spot sounds the best for the majority. What sounds best is not automatically what looks best and feels best.
It's like eating a fine meal like a filet mignon perfectly cooked to your personal preference with the right red wine bottle and accompanied with your favorite mistress @ her favorite restaurant.

Do we keep the grille on or off? ...When we cook our meal. Not if there is no fire in the fireplace and that we keep things hot bare skin...

 

[RayDunzl]

My experience/experiment says you can have some separation outside of the sweet spot but it takes much less than a millisecond
delay of the direct sound to create a detectable offset of the imaging, like .04 or even .02 millisecond (per my DSP).

A slight timing displacement affects me more than the volume difference. The example above gives ~4.36ms timing offset.

However, on Beer Saturdays here at Neverland East, John and I don't worry about it.

 

[AJ Soundfield]

Oh, sorry I went with the geometric design presented.

Cheers,

Gotcha. Yes that extreme case was used to make the measurements easier. How many CD designs have you heard with such toe-in?
The speakers you have pictured there are pardon the pun, polar opposites of CDs like what I'm referring to.

 

[NorthSky]

I do not think the speaker toe in issue concept is complicated at all. It is not about just the speaker, so there is no universal answer to what is best, like aim them X feet in front of you. Like most things that seem to be about speakers, this is actually about an integrated, complex sound delivery system including the speaker, the room and your ears, including how distant and how reflective are the surfaces on the side walls, ceiling and floor. Surely, what you hear is the result of direct plus reflected sound, unless you are listening with headphones (ugh!) or in a near field situation, something I also do not particularly like or recommend, especially if your wife is sitting fight next to you.

So, while that is conceptually not difficult to understand, achieving a sound that pleases you in most respects comes down to trial and error, involving subjective assessments of the result until you "get it right" for that speaker, its unique dispersion characteristics and how your room reacts to that.

It is quite amazing how so many speaker reviewers have commented on optimizing toe in, as if it only depended on the speaker.
Totally neglected in those reviews is the influence of their rooms on that "optimum".

Your post ↑ I like, very.

 

[NorthSky]

My experience/experiment says you can have some separation outside of the sweet spot but it takes much less than a millisecond
delay of the direct sound to create a detectable offset of the imaging, like .04 or even .02 millisecond (per my DSP).
A slight timing displacement affects me more than the volume difference. The example above gives ~4.36ms timing offset.
However, on Beer Saturdays here at Neverland East, John and I don't worry about it.

Coltrane?

 

[NorthSky]

Gotcha. Yes that extreme case was used to make the measurements easier. How many CD designs have you heard with such toe-in?
The speakers you have pictured there are pardon the pun, polar opposites of CDs like what I'm referring to.

With LPs I generally toe-in my speakers more, more than with CD listening.

 

[Mivera]

With LPs I generally toe-in my speakers more, more than with CD listening.

With DSD you can face them towards the rear wall and still get better sound.

 

[NorthSky]

With DSD you can face them towards the rear wall and still get better sound.

I believe you Mike.

* CD is Compulsive Disorder. ...Bipolar speakers, people speaking @ mass gatherings...Donald, on and off axes.
No amount of toe-in/toe-out can fix it, none.

 

[AJ Soundfield]

With LPs I generally toe-in my speakers more, more than with CD listening.

Hah.
Ok, so I'll take that as a no, you haven't heard a large controlled directivity speaker cross-fired like the example above...and the way the spatial rendering remains stable over a wide lateral area.
That's ok, most haven't.

cheers,

AJ

 

[NorthSky]

Hah.
Ok, so I'll take that as a no, you haven't heard a large controlled directivity speaker cross-fired like the example above...and the way the spatial rendering remains stable over a wide lateral area.
That's ok, most haven't.
cheers,
AJ

AJ, "a large controlled directivity speaker crossed-fired" ... is it like those THX speakers with narrow dispersion/directivity?

And no, my limited speaker's experience is mainly from wider dispersion/directivity speakers.

* We talk about room reflections from the adjacent walls, ceiling and floor, and toe-in.
In home theater rooms THX speakers were specially designed to have a narrow dispersion in the front soundstage, and dipolar dispersion from the four surrounds.
If a stereo sound system is to get rid of the first reflections, why don't they build more narrow directivity/dispersion speakers?

I'm honestly asking...to learn, and from you because you have much more experience than I in your line of work.
The speakers you designed have a wide dispersion tweeter design, right?

 

[AJ Soundfield]

AJ, "a large controlled directivity speaker crossed-fired" ... is it like those THX speakers with narrow dispersion/directivity?

Maybe, don't know much about THX. Like the Geddes speaker referred to in the illustration. Or big JBLs like Michaels 4367, etc. Yes my bigger systems too.
At demos for this arrangement, I put on say a voacls/jazz track and ask people to get up from the sweet spots and move to the wall left of the left speaker, IOW, outside of the speakers...and listen for where the soundstage remains and how stable, despite the large lateral movement. It's quite an ear opener for those with very wide dispersion speakers, where doing so would result in sound collapsing to the nearest speaker due to the intensity difference from the far speaker.

The speakers you designed have a wide dispersion tweeter design, right?

No, generally not. The only thing that would qualify so would be the supertweeters, because they are there to add sound power to the reverberant field, without tilting up the onset response. Every thing else is controlled, so that you have the effect in the illustration.
The secondary benefit of controlled directivy is less variance of SQ room to room than wide dispersion types.
Note I didn't say "better", just less variance.
You are quite right that spatial rendering is a personal preference, of which toe in plays a role, so of course there is no right or wrong, just taste. the CD/crossfire thing I showed above is for the specific effect of (very) wide listening area, 'tis all. that might be of zero importance to some.

cheers,

AJ

 

[NorthSky]

Great post AJ.

Yes, THX certified speakers have a narrow directivity, on the horizontal and vertical planes. ...Laterally.

Some speakers are designed with wide dispersion for spaciousness and with excellent off-axis frequency response. I use some of those, ...smooth.
And some speakers you can walk behind them and they still image (holographic) well. Now that's something else, isn't it!
{I used to walk behind my speakers when I was a kid.}

AJ, you brought up a good point; stand up and walk around listening to a pair of loudspeakers.
Put some piano music recording @ a fair volume level, walk out of the room, to another room and listen for that piano realism...
...Another good way to determine quality room acoustics with the speakers playing in it. ...Vice versa.

* Active vs passive music listening: Active is right around the middle sweet spot, and the amount of toe-in will make that sweet spot narrower or wider.
The triangulation between the three points (L & R speaker & Listener) will also dictate the ideal amount of toe-in, or not, or even toe-out.
...And the speaker design (its directivity and dispersion pattern), and the room acoustic properties, of course.

 

[NorthSky]

♠ http://www.acousticfrontiers.com/speaker-off-axis-understanding-the-effect-of-speaker-toe-in/

♦ http://www.acousticfrontiers.com/20...kers-open-up-your-acoustic-treatment-options/

♣ http://www.gcaudio.com/resources/howtos/speakerplacement.html

Toe-in depends on three factors: the particular speaker you have chosen, the room and your personal preference. Some speakers sound best with little or no toe-in, others may require a great deal to perform properly. Follow the manufacturer's recommendations or, lacking those, start with no toe-in and begin turning the speaker inward (pointing more toward the listener) until the right amount of center-fill is obtained, without sacrificing soundstage width.

You can use the "string method" described in calibrating the distance to each speaker, but this time measuring to both the inside and outside corners of each speaker. However, far and away the best method for setting toe-in employs a laser pointer. You'll need a "target" for the laser, ideally something positioned at ear level. a pillow propped up in the listening chair or a point on the wall behind the listener can be used as reference points. Simply place the pointer on top of the speaker, making certain it's square to the front of the enclosure, and adjust toe-in until the laser focuses at exactly the same point on your target.

Adjust the position of the target itself to correlate with the speaker manufacturers recommendation for where the speaker output should intersect. Speakers requiring a large amount of toe-in will intersect at or just behind the listener, that point moves further back when less toe-in is indicated. Some manufacturers are adamant regarding the amount of toe-in, others are less specific in their recommendations. In general, more toe-in increases center focus, but reducing stage width. Less toe-in widens the stage, but center focus will be sacrificed if you go too far. Sometimes it's a balancing act based on the room, the speaker and the preference of the listener.

Note: Toe-in and distance between the speakers are often interrelated. You may find that it will be necessary to revisit the distance between your speakers after you have experimented with toe-in.

 

[Fitzcaraldo215]

This might be warping the relevance for most here in the context of toe in. I have seen plenty of stereo listeners, reviewers included, obsess about toe in. But, the topic just does not seem to come up among multichannel listeners, like me. Since much of proper Mch setup is all focused on the sweet spot, we just tend to set up our speakers pointed dead at it. I have also seen this at the few recording control rooms I have visited.

Our speaker arrays in Mch are pretty well defined by Dolby or DTS for movies or ITU for music (they are all fairly compatible) in terms of a standard, defined angular layout and equal distance from the sweet spot. The distance issue is solved either by equidistant physical placement or it is corrected by DSP in time delay and volume level.

There are no such standards for stereo, and speaker placement has been totally loosey goosey in use and by tradition. There are rules of thumb, like equilateral triangle, but not everybody adheres to that. Toe in would seem to be a subjective fine-tuning adjustment for frequency balance and/or lateral imaging. Both are the result changing the mix of direct and reflected sound interactions with the room in a largely unpredictable way. We have no way of knowing what speaker placement the stereo recording engineers recorded, mixed and mastered for or used in their process, unlike Mch. We do not know exactly the soundstage image they were seeking in stereo or in Mch either.

Another current trend is the increasing use of a full range DSP EQ target curve, which is a different way, perhaps a superior way to toe in, to get the frequency balance where it is subjectively preferred. That is also quite common in Mch systems, and even some recording engineers now use it on their monitoring systems. The use of full range EQ would counteract some of the effects of toe in, at least in attempting to "improve" the frequency response of the system. But, "enhanced" imaging would seem to be the major goal of tweaking the toe in. Frequency response might be less affected by toe in if speaker directivity is more controlled, along the lines recommended by Toole.

Of course, the thought of fiddling with the toe in of 6 of the 7 (no toe in for the center channel) speakers in a 7.1 array is also not going to appeal to many. Besides, the spatial imaging is much more well defined by the discrete Mch recording process itself and delivered by the speaker array.

So, in my Mch setup, I just array the speakers according to the ITU angles, point them at the sweet spot with a laser, calibrate my EQ and distance correction, and I am mostly done. I look at the measured and predicted results. I might find it necessary to adjust the subwoofer location for better response and make separate measurements. But, my results have been pretty good and pretty satisfying that way. I lose no sleep over toe in.

THX was mentioned, by the way. It has its own speaker placement and speaker type directives - dipole or bipole surrounds not directly facing the sweet spot. But, I never liked it and the vague imaging it provides, especially on music. I also think it is passé these days compared to discrete formats like Dolby True HD and DTS HD Master Audio without adding a fuzzy wuzzy layer of additional processing.

 

[RayDunzl]

Martin Logan reQuest speakers here, stick a light on your nose, rotate the speaker until the reflection is 1/3 from the inner side, then set the rake using the vertical reflection height. That leaves them with the inner edge of the cabinet aimed at me.

In my case I have them tipped forward about 3 degrees so the vertical center of the panel is aimed at me.

They're about 44 inches from the wall behind, and there are drops due to backwave, I haven't adjusted that to be officially 'between' notes, though I might do that, uh, one of these days.

Eyes closed the speakers disappear audibly, with a very stable and convincing soundfield, completely recording dependent, which melts the walls and extends 180 degrees on occasion. I've had them since February 1998, so they are just 'there'.

If I close eyes and try to locate one speaker playing by walking toward it, when my nose touches the panel (they're a little taller than I am) it still sounds three feet away.

They are symmetrically placed on the short wall of the closed end of my open to the rest of the house on one corner 14x19x9 room.

Measurable reflections are seen ~1ms from the back of the couch under the mic, ~7ms from the backwave, and ~26ms as it bounces off the top of the wall behind the listening position, and back off the wall behind the speakers. No sidewall, floor, or ceiling reflections noticeable in an impulse response, or a slowed down recording of an impulsive noise burst.

I'm deaf enough not to be bothered by high frequency 'problems' that might bother you, they cross woofer to panel at 180Hz and show very flat phase response above the cross.