What is the ideal directivity pattern for stereo speakers?

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You see Scott - in Markus' world "Bauer is real" and "JBL Paragon is not real" :rolleyes:

I think he means "reference" as:

reference - definition of reference by the Free Online Dictionary, Thesaurus and Encyclopedia.

..5c: "A work frequently used as a source."

Under the context of it's operation, or *why* you might want to have such a distributive pattern of sound.

Unfortunately though, I don't even think that is true - in that I don't think Bauer in this context is "frequently used as a source". :eek:

I think the closest thing we can get to is that it's likely that Bauer has the first *thorough* explanation.

My only problem is that the statement "45° toe-in is an idea of Bauer" - makes it appear as if he was the *originator* of the idea - which he most certainly is not. Again, perhaps a slightly different phrasing would have expressed the communication in a manner that would not have resulted in this interpretation. :(
 
...Again, perhaps a slightly different phrasing would have expressed the communication in a manner that would not have resulted in this interpretation. :(

anyway, on to the matter, let's discuss ideal directivity pattern for stereo speakers
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So industry professionals and musicians have untrustworthy taste in stereo imaging matters?

We had a couple to our house once and I did a demo of my sound system. The wife of the couple finally blurted out: "I can hear sound from both speakers and even from between them". (Yes, its called stereo, its been around since the late 50s.)

I think this was the distinction between the professionals group and the "naive" group. (By the way, the authors used the term "naive" to apply to people with no particular audio knowledge, i.e. not concerned with "imaging precision" or such matters.) Everyone in both groups probably appreciated a spacious sound and a sense of envelopment. But if you are outside of audio world you aren't going to know that good stereo also involves an ability to make convincing and solid virtual sources at any position between the two speakers. Nobody in the non-pro group would know to trade off spaciousness for imaging precision.

What else would appeal to the half of the professionals group that preferred the drier sound? Less spaciousness?

Returning to the John Crabbe article, he offers a revealing test for a good stereo system: Your ability to differentiate between mono and stereo. He claims omnis are less revealing of the switchover because they "dilute the stereo image and inflate a mono signal to the point where they are rather similar". Compare that to headphones where, in spite of other problems, the switchover is always strongly obvious. The problem with speaker generated artifical ambience is that it is always there, whether the recording warrants it or not. Is that accuracy?

David S.
 
As far as the recording end of this topic is concerned, even a mono record of a singers(most are) played through a mono speaker does not sound like the singer. Not in any situation I have ever heard and I've heard it several times. You can hit in HRTF compensation button in my recording software that you can apply to whatever instrument you want or the whole recording. It is limited to a few angles though and I don't recall any height adjustments. Mono center is definitely one. I've never heard automagically make a singer sound more natural FWIW. Installing HRTF compensation is not a well thought out idea for loudspeaker designers. There's just no refuting it. Any sort of fighting the recording seems quite silly.

Dan
 
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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

Not sure who you're talking to and about what you want to talk. Maybe this paper can clear things up? http://www.sebastianmerchel.de/Projects/SweetSpotter/Merchel_Groth_SweetSpotter_AES126.pdf
 
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.

Yes and by aiming the speaker towards a side wall, (ipsi or contra), the lateral energy will increase, not decrease as you announced. And it is good thing to be increased, not the opposite as you suggested.

What comes to the toe out, it is not fully processed idea to simply toe out the speaker at the stereo triangle position, but it is adviced to move the speakers in the middle at front and then toe out, and heureka there you'll have it !

- Elias
 
Naive listeners don't prefer high sound quality?
Apparently not, in many cases, otherwise boom and tizz speakers, and the almost universal application of high levels of compression and limiting would not be so common place in pop music. After all, most speaker makers and recording engineers are just catering to the public at large, and what will sell, right ?
Why just not to say in plain english that naive listeners have bad taste?
Taste, and an ability to discern the quality level of sound reproduction are two different things.

Everyone has their own taste in music - both types of music, and how they like to hear it.

For example, some people like more bass and treble than others. More power to them. That's an expression of personal taste, and tone controls can come to the rescue. If they like their TV bright and blue, or with the saturation turned well up so everyone looks sun burnt, that can be arranged too.

However being able to judge quality and accuracy of sound reproduction takes a lot more skill and experience than just being able to form an opinion on what sounds you "like". Everyone has an opinion on what they do and don't like. Not everyone can offer a quantitative analysis of what's right and wrong in a given example of sound reproduction, at least not without some training.

In trained listeners there is usually a good correlation between quality, accuracy, and personal preference - the three tend to go hand in hand, with multiple trained listeners tending to give very consistent results.

In untrained listeners the correlation between accuracy and personal preference is not a given, in fact more often than not an exaggerated inaccurate response is often preferred, such as exaggerated colour or brightness on a TV, or a smile curve on a speaker.

It's not because these people are stupid or lacking in taste, usually they just don't know any better because it's what they're used to, not having experienced truly great sound reproduction, and without time spent critically listening to both great and mediocre sound, how are they to know any different ? (How does someone who is colour blind know what they're missing ?)

markus76's link to the Sean Olive paper is the perfect example - of all the subject groups that were tested, college students did the worst at picking out differences in speakers, (despite having the youngest ears) and tended to rate all the test speakers very highly and similarly to each other compared to other listening groups - because their frame of reference was most likely compressed mp3's (of heavily dynamically compressed and processed music) listened to on cheap ear buds on iPods.

When that's all you've ever listened to, any half decent high end speaker properly set up will sound amazing despite its flaws. The study did show that the college students appreciated the big jump in sound quality though, and enough exposure to that level of sound quality would probably eventually "re-calibrate" their expectations and make them more discerning listeners.

One of the biggest differences between a casual "naive" listener and an experienced critical listener is their level of expectation and familiarity with what can be achieved.
 
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So industry professionals and musicians have untrustworthy taste in stereo imaging matters?

nah, just about half of them, those suffering from the disease

We had a couple to our house once and I did a demo of my sound system. The wife of the couple finally blurted out: "I can hear sound from both speakers and even from between them". (Yes, its called stereo, its been around since the late 50s.)

I think this was the distinction between the professionals group and the "naive" group.

oh yeah? apparently Dr Toole thinks different. Have You read His comment?

But if you are outside of audio world you aren't going to know that good stereo also involves an ability to make convincing and solid virtual sources at any position between the two speakers. Nobody in the non-pro group would know to trade off spaciousness for imaging precision.

oh yeah? sorry - I'm with Linkwitz:

People listen differently. Performing musicians and members of the audience are used to different perspectives and focus on different aspects of the sound. Both are valuable for analyzing a loudspeaker. People who only listen to loudspeakers and thus always compare loudspeakers are poor judges of accuracy.


Very few sales people of "high end audio" ever listen to unamplified life sounds. They are highly susceptible to marketing department suggestions.


Unbiased listeners have no difficulty recognizing accurate sound reproduction, even with hearing damage or with hearing aids.

What else would appeal to the half of the professionals group that preferred the drier sound? Less spaciousness?

You haven't really read Toole, have You?

Returning to the John Crabbe

John Crabbe? long term editor of HIFi News etc.?

once again let me ask SL to comment:

People who only listen to loudspeakers and thus always compare loudspeakers are poor judges of accuracy.


Very few sales people of "high end audio" ever listen to unamplified life sounds. They are highly susceptible to marketing department suggestions.

HiFi press guys are typically even more biased than pro guys, I would say that at least 80% of them got the disease

but some are healthy and therefore from time to time omni speakers even win HiFi press awards for best sound of the year etc.

despite being not good stereo-hardly stereo at all-a firm step backwards :rolleyes: :rofl:
 
Yes and by aiming the speaker towards a side wall, (ipsi or contra), the lateral energy will increase, not decrease as you announced. And it is good thing to be increased, not the opposite as you suggested.

Energy from the ipsilateral wall will decrease, not increase. Contralateral energy is probably below threshold anyway so perceptually the influence of lateral reflections decreases. That's the whole point in a high directivity design. If a decrease in lateral energy is good or bad is a different question.

What comes to the toe out, it is not fully processed idea to simply toe out the speaker at the stereo triangle position, but it is adviced to move the speakers in the middle at front and then toe out, and heureka there you'll have it !

- Elias

Been there, done that:

An externally hosted image should be here but it was not working when we last tested it.
 
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So industry professionals and musicians have untrustworthy taste in stereo imaging matters?

It certainly appears that way, at least for the half of the industry professionals.


We had a couple to our house once and I did a demo of my sound system. The wife of the couple finally blurted out: "I can hear sound from both speakers and even from between them". (Yes, its called stereo, its been around since the late 50s.)
David S.

I trust that was a genuine perception. There you see, a real world example that your stereo didn't work, but the sound was coming from the speakers ! Occasionally it apparently works because some sound was coming between the speakers too.


- Elias
 
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.
It needs to be clarified here that toeing in a directional speaker more will only increase the energy level reflecting off the contra-lateral wall relative to the same speaker at a lesser toe in angle - it will not be increasing it relative to a wide dispersion speaker, which will still have an equal or greater reflection level from the contra-lateral wall more or less regardless of toe in.

With a typical toed in front of the listener angle for a directional speaker the reflection from the contra-lateral wall will be equal or less than the wide dispersion speaker, while the ipsi-lateral wall reflection will be greatly reduced.

If the directional speaker is constant directivity, the response on the listener axis will also be much the same as the conventionally toed wide dispersion speaker.
 
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HiFi press guys are typically even more biased than pro guys, I would say that at least 80% of them got the disease

but some are healthy and therefore from time to time omni speakers even win HiFi press awards for best sound of the year etc.



Just about every time a read a hifi article on "omni's", it almost always goes like this:

"Wow! Great X, great y, great z.. etc.. Somewhat more diffuse imaging, though probably closer to reality. etc.."

-and then predictably they write it off as a curiosity, never purchase the pair, and never refer back to them meaningfully in later reviews of other loudspeaker designs. :smash:

I'm not going to advocate that omni's are the best period, and I certainly would advocate that they are the best for any given person.. BUT,

Reviews like this just don't make any sense. They usually admit that such a design presents a more compelling reproduction, yet they don't like it - or more correctly: don't like it *enough*.

It just goes to show that this hobby of ours is *very* much an "art" at the end of the day.
 
Been there, done that:

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


No you haven't ! Where is the pillow ? :D

Honestly it looks more like toe up. Unless you got that mushroom to work amazingly against physics?

I suspect you got too much of direct sound there.

Did you measure the level of direct sound and wall reflections ?

- Elias
 
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