Why evaluating the sound of a single speaker is essential

[tmtomh]

I did not imply that. My guess would be, separated tests in mono and stereo would be sufficient in order to have a valid result for real source localization formats and phantom localization formats. Any other potential configuration is based on either of these principles or a combination thereof.

You absolutely implied that - as @Mnyb pointed out, the logical implication of your claim is that controlled listening tests are only valid for the number of channels used in that particular test. There is no logical or scientific reason why one-speaker tests would be invalid for stereo BUT 2-speaker tests would nevertheless be valid for 10-channel.

So when you write, “I didn’t imply that,” what you’re really saying is, “I didn’t mean that” - a crucial difference because it means you didn’t think through the implications of what you were claiming.

And that, in turn, is why you then have to write, “my guess is that… would be sufficient.” You’re just making up a scenario for scientific validity (“would be sufficient”) based on what feels like common sense to you (“my guess is…”). This is precisely the lack of scientific evidence, and the kind of unsupported, almost arbitrary pronouncements that @amirm and and others are noticing and critiquing.

 

[olieb]

Some features such as tonality/coloration/resonances can be evaluated in mono, but those three words are not synonymous with "everything".

I did not say anything about "synonymous", you might want to look up what "to build on" means.
"tonality/coloration/resonances" is basically the same thing, said three times. But there is more that can be evaluated in mono.
A speaker in the first place has linear characteristics of directivity/radiation pattern with magnitude and phase FR for each direction, and then there is the deviation from linearity, which is a collection of different "distortions" (some of which like transients are not that easy to evaluate). All of this can be listened to and analysed in mono.

Aside from that, what exactly is your point, or did you just want to be a bit rude and tell everybody they were wrong and parroting nonsense while you know better but have nothing to show for your point? Is that really the level at which you want to discuss?
And I do not get at all what your not so short but a bit confused list of quotes is supposed to tell us.

EDIT: This is my take on stereo vs mono.
When listening in stereo there are some things that are different/new.
The stereo triangle puts the speakers at ±30° azimuth positions (and the listener might not be on axis).
The spatial cues from two channels (of related signals) interfere/overlay with the spatial cues from the radiation in the listening room.
One effect of interest might be that phantom (center) sources are not accompanied with a radiation pattern that emanates from the position of the virtual source.
In some kind of recordings there are hard panned tracks that are effectively reproduce in mono from the left or the right speaker, so stereo in this situation is actually a blend of phantom and mono sources.

Whether and how much this impacts the preference in stereo in such a way that characteristics are evaluated genuinely differently than in mono ist not at all clear. The Harman research seems to indicate that it is rare for typical "front firing" speakers to turn the preference upside down in stereo.
The main aspect here is probably the width of the radiation. In multichannel/stereo the "optimum" (if there is one) might be narrower than in mono. But that is just a guess on my part.
And driver time alignment and diffraction from the baffle (edges) might play a different (detrimental) role in stereo imaging than with mono "spaciousness".
I would really like to see evidence on the impact of these genuine stereo effects. Otherwise it is just forcing opinions on others and that surely is not what science should be, but what you so generously imply others to do.

 

[Heinrich]

---...---
And driver time alignment and diffraction from the baffle (edges) might play a different (detrimental) role in stereo imaging than with mono "spaciousness".
I would really like to see evidence on the impact of these genuine stereo effects. ---...---

The stereo 'image' again. As a scientist would you mind to reveal it as an illusion by the powers of your mind? Serious, what would you do to concentrate on reality, debunking the illusion?

Thing is, with stereo you have cross-talk left/right ear. That particlularily blurs the image before consciousness, but after the fact it is accepted. The stereo-head's mind has to ignore this in performing reality shaping (LOL). With that resonances are also ignored, as they have a similar 'gestalt'. What do you think?

Several times me posted a link to the thesis of Dr. Gunther Theile, available in plain English, but it was entirely ignored. Maybe it was for your own good.

 

[amirm]

A proper study to answer ´are mono test results valid for stereo?´

Huh? For what purpose? You sure you are following the purpose of the research?

The idea of single speaker testing is that it is more revealing of tonality errors than 2 or more speaker setups. And tonality errors are the #1 sin of speaker designs. Get that wrong and you have coloration on everything you play. I don't care how much you fall in love with spatial qualities of a dipole speaker. If it has resonances, it has resonances that need to be fixed and that is best detected in mono.

Indeed, I think the reason so many bad speakers sell is that people keep listening in stereo and fall in love with that spatial effect, not learning or being aware of the faults of the speaker.

In my reviews, I show frequency response measurements. This too is done on one speaker. It then reasons that we listen to the speaker by itself and determine whether we agree or disagree with those measurements. Sticking a second speaker in there, playing different spectral energy that is mixed with it is no way to answer this question.

 

[amirm]

Could you link to an independent documented study to support your claim, focussing on preference ratings (not discrimination) while involving typical aspects of stereo reproduction, conducted in the last 20 years, please?

Huh? What does last 20 year have to do with it. Fletcher-Munson equal loudness tests were performed some 80 years ago. You are going to dismiss that and ask for something new? To what end? Has human hearing changed?

As Dr. Toole showed, and I have said many times, the foundation of much of his research is from when he was part of independent Canadian national research commission (NRC). Even if we were talking about their work at Harman, his work has superb credibility. Certainly, far, far more than your appeals to this and that person with zero published data or research to invalidate the work we are talking about.

It is your job to come up with studies that counter what has been shown to be true in study after study by Dr. Toole's team. That you don't have this research ends any argument you have. It is not our job to keep coming up with more, just to have you refuse it with, "my mixing friends say the opposite." Your mixing friends need to start reading and learning the research and put it to practice.

 

[amirm]

Not only training in reliably detecting tonality errors, but blind testing such abilities as a part of their university education.

Let's see evidence of said ability. I post how Harman trained listeners did. Do you have this for them? Of course not.

 

[kimmosto]

And driver time alignment and diffraction from the baffle (edges) might play a different (detrimental) role in stereo imaging than with mono "spaciousness".

Exactly and without doubts. Listening suitable record having wide-band sound panning from center to side reveals problem due to bad timing. This is obvious, known psycho-acoustics and fault is quite common in conventional multi-way speakers. It could be audible also in mono as a small vertical movement, but mono does/can not explode phantom image as much as stereo. Problems due to diffraction are more difficult to forecast, but some differences between mono and stereo should exist.
I've not tested these in almost two decades so some details may be lost.

 

[Thomas Savage]

Can we get back to the OP , its a interesting and not fully filled out subject.

What was one of the best threads has turned into noise ..

We have an issue and always have , representing the results of science isn't the same as offering a platform for scientific examination itself.

That hurts , forgive us , we're just a text based forum ! Still that works both ways so I suggest we make room , we are all limited here .

 

[amirm]

Problems due to diffraction are more difficult to forecast, but some differences between mono and stereo should exist.

I wouldn't trust a single person on audibility of such artifacts. This is why we have measurements. Subjective uncontrolled testing is just a small compliment to measurements in a review. Anyone confused about this is firmly in anti science subjective world.

 

[kimmosto]

I wouldn't trust a single person on audibility of such artifacts. This is why we have measurements. Subjective uncontrolled testing is just a small compliment to measurements in a review. Anyone confused about this is firmly in anti science subjective world.

Is this some general advertisement or indirect harassment by hinting that just a single person listened the speaker and test tracks, and it was not measured before or after that event? I measured the speakers quite enough. How about you?

 

[Thomas_A]

Seems a neverending story. There is published research on this topic. So far no one has published research showing that two speakers would be better in judging speaker quality. There are some unanswered questions. Either some reasercher with funds and interest does it (unlikely) or there is crowdfunding research to be done somwhere. ASR? Publishing can be done.

 

[Salt]

Where do we go now ....?
Seriously.

 

[Newman]

Where do we go now ....?
Seriously.

How about 40 members here accepting post #1 and dropping the denials? That would be a good place to go now.
Seriously.

 

[Salt]

How about 40 members here accepting post #1 and dropping the denials? That would be a good place to go now.
Seriously.

Thanks.
Might reduce time and effort of following threads ...

 

[Timcognito]

Well just like most things measuring produces solid metrics that allows one to do side by side comparison if all parameters and measuring equipment are the same. It is ironic that how to measure with your ears is can be fraught with so many beliefs in how to do it in most scientific way when it is clear that it is clearly a highly subjective thing. And yet the connection to audibility must be iron clad if the the measurements are to be believed. In statistics that would require a well defined success/failure criteria and low p value. It is simple in my mind that the calibrated microphone is a better listener in every way and as with all things compared, the measurement must follow a set and simple protocol to make that comparison valid.

 

[Davey]

Two identical speakers in their normal listening position, but with the mono switch activated on the preamp.
Not valid in the context of this premise/evaluation method????

Maybe this has already been queried in this interminably long thread??

 

[Timcognito]

Two identical speakers in their normal listening position, but with the mono switch activated on the preamp.
Not valid in the context of this premise/evaluation method????

Maybe this has already been queried in this interminably long thread??

Dr Toole covers that in the first post in this tread. FYI

 

[Davey]

Dr Toole covers that in the first post in this tread. FYI

No, he doesn't. Not really. (In my opinion.)
Read it again please.

Regardless, I think the concept is sound and don't disagree with it. A single speaker judgement of tonality is perfectly valid and an excellent way to approach it.

 

[Timcognito]

No, he doesn't. Not really. (In my opinion.)
Read it again please.

Regardless, I think the concept is sound and don't disagree with it. A single speaker judgement of tonality is perfectly valid and an excellent way to approach it.

From his paper in that post and as you say I too am onboard with it.

"As has been well publicized, listeners are far more critical in their assessments of sound quality
when listening to a single loudspeaker. This fact has generated a fairly constant stream of flak
from those thinking that stereo is a more rigorous test and that listening in mono was all but
irrelevant. However, decades of double-blind tests show that listeners hear problems in
loudspeakers more readily when listening in mono. The superior sound quality was less clearly
reflected in scores in stereo comparison tests, and even less in multichannel evaluations.
Monophonic components exist in stereo and multichannel programs, so designing loudspeakers
to meet the most stringent (mono) test was considered worthwhile. But, the question remains;
why? Were the audible defects more clearly revealed because the spatial complexity and inherent
amplitude/phase distortions of stereo were absent? Is this why headphone listening has such an
almost magical clarity? One sound to each ear, not two. It does seem reasonable."

 

[RickS]

Is this some general advertisement or indirect harassment by hinting that just a single person listened the speaker and test tracks, and it was not measured before or after that event? I measured the speakers quite enough. How about you?

Amir’s count of speakers is over 300 and most of that is within the last few years. Trust that you have measured plenty too but let’s try to focus on how to work better together. Thanks!