What is the ideal directivity pattern for stereo speakers?

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Naive listeners also prefer the sound of the "smile curve" (otherwise known as boom and tizz, or loudness contour) over a flat response. Does that make it correct or more accurate ? No..... :D

Most naive listeners also prefer highly compressed audio (dynamic range compression, not mp3 compression) simply because it "sounds louder", even though it may fatigue them in the long term. Does that make it correct or more accurate ?

Most naive TV viewers also prefer the "torch mode" of a TV, which is the mode that TV's are put into in stores which makes the picture very bright, contrasty and bluish in tone to compete with other TV's and fluorescent lighting in the store. Most viewers don't know any better and will leave their TV in this mode at home unless the instruction manual explicitly tells them to change it, or they have it calibrated by a professional, and even then they will probably find it "too dim and yellow", even though it's now more accurate.

Asking a naive listener their opinion on what sounds best (especially when they have heard a limited range of system types before) is a bit like asking someone that knows nothing about wine tasting which of two wines is best, and why.

You won't find out which wine is better, only which wine naive wine drinkers prefer ;)

Likewise asking a group of naive listeners which sound configuration sounds better will only tell you which configuration naive listeners exposed to typical systems prefer, not which system is "better". I wouldn't place too much faith in sound quality testing done with naive listeners, as listening in itself is a skill that has to be learnt.

Amen!
 
No ! Trained vs. untrained people listen and rate equally good. It only takes some more time for the untrained "to fill in the questionnaire".
Having had many conversations with "untrained" listeners on how a certain set of speakers or stereo sounds before, I disagree.

If you're asking them for their personal preference, yes. If you're asking them to judge sound quality, forget it, unless there is a clear and unambiguous winner between two systems.

Untrained listeners may hear "something different" between two different but comparable speakers, however they are unable to recognise in what way each system may be deficient, especially if the aberration is a linear distortion, like a frequency response error, or frequency dependent dynamic range compression.

For example, certain frequency response errors (smile curve etc) are often "preferred" over a flat response, and picked as "better".

It takes a lot of experience and exposure to sound systems of varying quality to be able to make judgements about and describe the relative merit of two systems that are different but within the same order of magnitude in quality, without being "sucked in" by Euphonic distortions in the response.

Building speakers is particularly good for learning to "listen" because you are typically starting off with raw drivers with, at the very least, frequency response deficiencies, (and maybe resonances to correct) and as the "problems" in the response are corrected one by one you learn the characteristic sound of each type of problem, and can then recognise uncorrected problems in other speakers...
 
But there are more reasons behind. I believe most normal people do not want to be surrounded by the orchestra or the band. If you go to live concert the sound will come from the stage, which in a field concert is in very narrow angle maybe 10 degrees.

And then there is the evolutionary survival theory that sound from the back are considered threathning and not pleasant, and thus they should be avoided.

The only reason for more than 2 loudspeakers are to generate the surrounding ambiance reverberant field.

(Movies are another matter but not interested.)

- Elias
I totally agree with your comment. Back in 1976, when the first "bucket brigade" audio delay chip became available (Popular Electronics mag?), I was thrilled to no end about rigging up a quad sound system with it. After doing that I realized that I didn't like being surrounded by all the noise. Sure, a single delay isn't very real sounding, but it was more about it all just being too much. Surround sound is still a primary focus of my audio engineering hobby all these years later, and I'm still only interested in a half circle of five channels. Steered surround may be preferred for movies (although dialog can be hard to hear when it comes out of the center speaker only sometimes), but for music I prefer a passive surround extraction (L+R center and what I call L-XR for sides - front left and right I generally leave alone), with the side channel signals going through a good digital reverb (Lexicon MX400). I came up with a circuit that cancels most of the L+R out of the side channels, without collapsing them into a mono signal.
 
45° toe-in is an idea of Bauer ("Broadening the Area of Stereophonic Perception", JAES 8) from the 60s which helps to broaden the sweet spot. The nice side effect is a reduction in lateral energy but the room has to have a certain shape/size so the more delayed contralateral reflections isn't too prominent. That's the only downside.

I think Bauer was too stingy in his toe ! He could have toed them all the way 90 degrees, placed them back to back and had invented pre-stereolithic sound projector !

Anyway, he propably too had his prejudices so let's forgive him.


Markus ! How is lateral energy reduced if speaker is aimed towards the side wall ? And why it is nice to reduce lateral energy ? Haven't you been reading Toole ?


- Elias
 
A high direct to reflected ratio would sound alien to most naive listeners.


Of course something unnatural sound alien ! Why half of the industry professionals are not able to hear that ?

Direct to reflected ratio should not be any higher than in a real event. In real life situation the ratio is usually very low.

It must be that the half of the industry professionals have twisted priorities, unnatural ones.
But only half of them, luckily, since half of industry professional prefer omnis :D


- Elias
 
Markus ! How is lateral energy reduced if speaker is aimed towards the side wall ? And why it is nice to reduce lateral energy ? Haven't you been reading Toole ?


- Elias

Seriously? Want me to draw a picture for you?
The original context was your claim that "we" would need to toe-in high directivity speakers because "we" couldn't "take it directly facing" us. That's not the reason. Just go back a couple of posts, several people tried to explain the reasoning.
 
Markus ! How is lateral energy reduced if speaker is aimed towards the side wall ? And why it is nice to reduce lateral energy ? Haven't you been reading Toole ?


- Elias
Unless different walls have different absorption functions, the energy doesn't change. However, in typical rooms, toeing in the speakers usually increases the delay between the direct sound and the first (strongest) reflection, which according to some, allows for a better stereo image.
 
..45° toe-in is an idea of Bauer..


Jordan was doing this in stereo before it existed commercially. (..and I wouldn't be at all surprised if some of the WE people were doing it in mono (dual channel) for a wider spread in theaters earlier than that.)

It's all too predictable that something gets created/invented, and only later is "defined" by the academic community.
 
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I'm not trying to argue about anything. Bauer is just the only "real" reference one can link to when talking about the idea of "toe-in".

The second post was just an FYI. :eek:

I'm also thinking that Ranger and others probably came to a similar conclusion using horns in corners in homes.. and I"m sure many of which were klipschorns by the time stereo was introduced commercially.

As for a "real" reference - there probably were internal documents from various co.s that broached the subject more academically, an in fact even Ranger's document listed on that web page does that to some extent..

Perhaps then Bauer's article was not "real" (for any document is "real"), but rather *better* - though distinctly later. :)
 
Seriously? Want me to draw a picture for you?
The original context was your claim that "we" would need to toe-in high directivity speakers because "we" couldn't "take it directly facing" us. That's not the reason. Just go back a couple of posts, several people tried to explain the reasoning.

The point is that the lateral energy increases if aiming speaker towards side wall, and increased lateral reflections are good, according Toole among others.

Myabe you tried to say the same thing but didn't quite succeed?

- Elias
 
Is it as simple as sophisticated listeners prefer directional speakers and less sophisticated listeners, omnis?

David S.

so, concluding, is it rather as simple as some sophisticated listeners - about a half - prefer directional speakers as a result of a kind of occupational disease?

cool2.gif
 
The second post was just an FYI. :eek:

I'm also thinking that Ranger and others probably came to a similar conclusion using horns in corners in homes.. and I"m sure many of which were klipschorns by the time stereo was introduced commercially.

As for a "real" reference - there probably were internal documents from various co.s that broached the subject more academically, an in fact even Ranger's document listed on that web page does that to some extent..

Perhaps then Bauer's article was not "real" (for any document is "real"), but rather *better* - though distinctly later. :)

A lot of posts about nothing :) Replace "idea of Bauer" with "first documented by Bauer" in my original post. Hope this is more appropriate.
 
Toe in ! The allmighty conspiracy.

Time intensity trading takes place between arrival time differences of 0 - 700 us.
Whereas to keep the image in place at 700us the required amplitude boost is 10 dB.
Beyond 700 us trading is not possible.

An externally hosted image should be here but it was not working when we last tested it.


700 us corresponds distance difference about 20 cm.

First of all, show me a device which actually generates 10 dB sound level difference within such a tiny lateral movement !


- Elias
 
The point is that the lateral energy increases if aiming speaker towards side wall, and increased lateral reflections are good, according Toole among others.

Myabe you tried to say the same thing but didn't quite succeed?

- Elias

Elias, we (?) were discussing why one would want to toe-in a high directivity speaker. The reason is described in Bauer's paper. Most people use a high directivity design to decrease reflections. Toe-in will decrease the energy coming from the ipsilateral wall while increasing the energy coming from the contralateral wall. The latter is more delayed and lower in level and in most cases probably below perception threshold.
If you want to increase the level of ipsilateral reflections then you would need to toe-out the speaker but this will reduce the sweet spot considerably.
 
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