A Broad Discussion of Speakers with Major Audio Luminaries

[kimmosto]

He needs to act more professionally and be respectful of others around him especially in this forum where we have so many knowledgeable people contributing.

You're absolutely right that I haven't shown or pretended respect if it's not earned in my opinion.

Everybody has an access to for example AES eLib to search the studies I have mentioned about timing. Lib is behind payment barrier also for AES members, but I can show a short summary what I have found and downloaded from there:

I'm know that this is not all, but until more information is shown, audibility was found when GD >= 1.6 ms. Just 3/7 was done with speakers, and probably just one with signal suitable for evaluating possible drop in dynamics due to delay at L.F.

Opponent has not yet referred anything, but I'm aware of paragraphs 4.8.1 and 4.8.2 in Toole's 3rd edition (I have it). He lists few more studies, partly done in reflective environment, but not mentioned in the book how large radiators and where, how much directivity, acoustics, distances. Effect of GD 1.6-2 ms is said to be subtle with addition "These numbers are not exceeded by normal domestic and monitor loudspeakers". I know that there are speakers on the market having double...tripple of that. One speaker had so long excess group delay that woofer's impulse did not properly fit into same time window of ca. 4 ms with tweeters impulse. Thousands of sold units already so what is "normal", and what is the limit which pays your attention? Is it "HF now and LF after few seconds" enough or what?

j_j wrote something like this: "Science tries to offers information with good confidence. Not truth". That statement and person is what I respect. So science does(/should) not try to prevent telling subjective experience, leaving possibility for further investigations and changes. As already written, most worrying is that existing references and conclusions are translated like an end game science which has offered final truth, and objectively measurable (audible) error will not be measured or published in human readable format.

 

[DanielT]

But the market needs products of many sizes, power handling capabilities, styles and prices to meet the needs of consumers.

Thank you for your commitment here at ASR. I read your posts with appreciation and interest.

I know you usually talk about the importance of bass, good bass to get a good music experience. I think even non-HiFi enthusiasts would agree with that.

I think the bass thing is something that non-HiFi enthusiasts even weigh in their purchase of Bluetooth speakers. Price, size, features plus bass capability. In any case, that was exactly what my niece did when she bought her Bluetooth speaker. She ended up choosing a slightly larger one of the two she was considering. So a little, with an emphasis on a little, better bass she got, but in my eyes rather pointless considering that she only bought one speaker.
I didn't preach any HiFi to her. She can do as she wants. She will, however, listen to my HiFi system in the summer cottage this summer when she visits. We'll see what happens after that.

By the way. I tested the neighbor's luxury racer bike. His hobby is bikes combined with midlife crisis plus exercise madness. In any case. Absolutely a cool bike but it won't make me abandon my half-rusty crap bike because of that experience and buy a similar one like he has.
My niece: Absolutely, my uncle's HiFi sounded really good but....That's what I suspect it will be.
(I might sand off the rust, put some rust stop on and then some spray paint on my bike though.)

 

[MarkS]

I may have read somewhere else that in the Harman room, the front wall is covered with acoustic foam behind the curtain so the dipole is effectively a narrow radiating monopole.

Well even if that's not the case, those horizontal metal bars just behind the ML are not exactly optimal ...

An fair evaluation of a speaker with a lot of rear radiation requires a set-up that takes that into account.

 

[Purité Audio]

The metal frames are affixed to the rear wall, and that wall is at least a metre behind the speaker in circuit.
Keith

 

[Heinrich]

Why do you tend to such incorrect accusations and generalisations? Where did this whole bord denial him?
Could you please post some more specific details to such as this is really interesting.

No, I do not mean to be mean in any way. I'm a bit disapointed, that's all. I better leave the discussion. No bad feelings.

 

[Esprit]

Finns, and other Europeans, can often come across that way.

 

[Heinrich]

Do you mean that there are just as many people in recording falling for snake oil or something like that?

Maybe, but funny thing is, if it is snakeoil it won't do anything real, hence won't ruin the recording for the customer? So, why bother?

Not picking on you, an entirely general observation. It is hard to debunk bad argumentation, because you first have to understand it, which is logically a challenge (it hurts). Because I feel it to be more positive, I gave a hint on how to evaluate what to expect from mixing/recording engineers in special regard to spectral balance, the very topic of the spinorama. Nobody picked that up, but wide spread speculation went on and on. Suspicions, accusations, logical twists etc. There's no conclusive "theory", and hence no experiment to falsify it.

Let a bunch of sound engineers mix a recording using one speaker. Let them do it again over another speaker. Measure the difference. Check if it was the tonal balance alone, or the relative amplitude of singled out microphone tracks etc pp also. Find (a) the tonal disbalance between the two speaker (pairs) in numbers of dB at frequencies a, b, c. Cross check (b) if there is more than just amplitude frequency response and directivity. Double cross check if a Harman trained listener is more picky if s/he is allowed to alter the balance of one of the mixes created. And so forth. This could be discussed as a German "gedankenexperiment" (thought experiment). Just because we are gentlemen, sportsmen even, right?

 

[goat76]

Let a bunch of sound engineers mix a recording using one speaker. Let them do it again over another speaker. Measure the difference. Check if it was the tonal balance alone, or the relative amplitude of singled out microphone tracks etc pp also. Find (a) the tonal disbalance between the two speaker (pairs) in numbers of dB at frequencies a, b, c. Cross check (b) if there is more than just amplitude frequency response and directivity. Double cross check if a Harman trained listener is more picky if s/he is allowed to alter the balance of one of the mixes created. And so forth. This could be discussed as a German "gedankenexperiment" (thought experiment). Just because we are gentlemen, sportsmen even, right?

I guess trained listeners means that they got trained until they could, with great consistency, discern tonality differences. In general, that should mean that most of these trained listeners got better and better with more time training. So, how many hours did they get trained compared to, say, a mastering engineer who has worked 10 hours a day, 5 days a week, for the last 10 or 20 years?

I can't see why a guy who got a few months or maybe a year(?) of listening training at Harman would be better at hearing tonality problems than a guy who has already been doing it professionally for 10 or 20 years. More training should, in general, mean you get better at it, don't you think?

I would definitely want to see a German "gedankenexperiment" on this.

 

[Heinrich]

I guess trained listeners means that they got trained until they could, with great consistency, discern tonality differences. ...
I would definitely want to see a German "gedankenexperiment" on this.

Soundengineer Zack gets a master tape in for final tuning, tonal balance only. He uses a pair of speakers Type Galactic Cluster 29m/k in room #22. Since he had European breakfast he's satisfied eventually. We hand over the result to trained listener Alberta. She and Zack never met, and will not meet until the proceedings are done.

Zack: pro/ since before the begining of time, knows every microphone type from its sound signature, knows from sound alone where it was placed, knows every compressor type by its name, and its production year, besides double checks the tuning of the piano, listens to timing accuracy of the rhythm guitar, but otherwise is not a fan of academic jazz music ...
Alberta: trained on tonality 'issues' (sorry), and knows nothing of the above, nor that it even existed, but is otherwise a happy consumer of regular radio shows ...

Alberta moves to room #21, which is equivalent in speakers and acoustics to #22, but not the same, and listens bringing forward her skills. (With a little help) she is going to change, or not, the tonality of the recording to her liking.

Zack re-evaluates the result. Will he be tempted to meet Alberta for a discussion?

Look, besides being a bit romantic, this is a quite direct path from record production to a (semi) layman's judgement, and more so, with feedback! It might be practical, but most probably it is not. That's why it is a 'gedankenexperiment' (it's virtual). But it reveals many the difficulties of such an assessment, me thinks in all modesty.

When it comes to speaker assessment in general, I asked some time back, if there's an equivalence of speakers, that rank high enough on the Olive's scale? It rephrases the question, what is 'good enough'? I'm not an engineer, but what I've learned is, that 'perfection' distracts from 'good', but only the 'good' is actually achievable.

 

[Floyd Toole]

Which would put a lot of speaker R&D efforts of the last 30 years under doubt, focussing on the ´smooth directivity´, accepting a steep and significant increase in d.i.

This, of course, is a matter that we have been much aware of. My first computer "simulation" of a room curve using anechoic date, ca. 1985, showed that above about 5 kHz the direct sound progressively dominated what was measured. All highly rated loudspeakers had flat and smooth on-axis frequency responses. Many more measurements since then, and Sean Olive's correlation study confirmed the importance of the direct sound in sound quality assessments. When trained listeners "drew" what they heard, they drew the on-axis frequency response, not the room curve. The off-axis sounds are subject to longer propagation path lengths (-6 dB/double distance) and to correspondingly increased air attenuation at frequencies above about 1 kHz. Put the two together, and even an omni, dipole or dipole loudspeaker will show attenuation of the steady-state sound field as a function of frequency. When comparing such loudspeakers with conventional forward-firing loudspeakers in double-blind listening tests, it is remarkable how similar they sound in spite of the differences in directivity - that is the dominance of the direct sound. So, how important is directivity? I don't know of an independent metric that correlates with listener preference, except that smoothness - i.e. absence of evidence of resonances - remains important. I have lived with and enjoyed forward firing and bipole (almost omni) loudspeakers that were timbrally neutral.

This phenomenon is evident when listening in concert halls where the reverberant sound field dominates beyond the first few rows (the critical distance). This reverberant field is massively rolled off at high frequencies, yet well into it the sound remains clear and well balanced. Yet, as distance increases, even the direct sound is rolled off due to air attenuation, it is reduced in amplitude relative to the reverberation, and everything becomes duller. Propagation loss and air absorption are inescapable.

 

[Keith_W]

This, of course, is a matter that we have been much aware of. My first computer "simulation" of a room curve using anechoic date, ca. 1985, showed that above about 5 kHz the direct sound progressively dominated what was measured.

Did you mean to say, "the direct sound progressively dominated what was heard"?

 

[Thomas Savage]

You're absolutely right that I haven't shown or pretended respect if it's not earner in my opinion.

@amirm , no Koobideh Kabab and tahdig for this guy, id not even open the special tea draw !

 

[Floyd Toole]

So science does(/should) not try to prevent telling subjective experience, leaving possibility for further investigations and changes. As already written, most worrying is that existing references and conclusions are translated like an end game science which has offered final truth, and objectively measurable (audible) error will not be measured or published in human readable format.

I guess my only thoughts with respect to this are that, as scientists, we report results of investigations attempting to shed light on specific questions. The measurement part is easy - they are repeatable by any competent person making them. The challenge is in dealing with the often capricious, adaptable, moody, opinionated, human listeners upon whom we rely to identify any useful relationships between what is measured and what is heard. Adequately controlled, double-blind listening tests are hard work and time consuming. We do what we can, but we don't have all the answers . . . and finding them must rely on subjective data. There are experiments done under laboratory conditions, and those that attempt to be realistic. Both are useful, "truths" of a kind, but some things are only audible under atypical circumstances with contrived sounds. They are "real" but not realistic. Small rooms are not small problems. There are few things that can be declared "final truths", but there are definitely some things that are close enough to be trustworthy guides.

A wise person said that God exists to explain where science has yet to go, and science is ever expanding. So, keep the faith - in science.

 

[Floyd Toole]

Did you mean to say, "the direct sound progressively dominated what was heard"?

No, but that is also true, it appears. I discuss this.

 

[Heinrich]

... yet well into it the sound remains clear and well balanced. ...

Did you mean to say, "the direct sound progressively dominated what was heard...

Well, with your permission, Dr Guenther Theile published findings on how timbral balance is affected by missing an idenfication of a sound source, lol. I suggested to read that short piece once in a while, it's science. I linked it several times, maybe seven, without *any* reaction? Now you may find it using artificial intelligence under: Guenther Theile superimposed sound field 1980.

Excerpt: the feeling of a balanced sound depends on brain activities that take localisation into accout, in other words, what you "hear" is NOT a mirror of what pysically reaches the ear(s). Not to the least. To put it even another way round, what you think of a tonal balance depends on what you imagine where in space its source may be.

 

[JPA]

You seem to have good command of English language but what you write is extremely hard to follow. Partially it is your ego getting in the way constantly but it goes beyond that. It just seems like stream of consciousness at times.

But no, there is no substitute to sitting in a controlled double blind test of multiple speakers. Only arrogance would say that when it comes to speakers, listening in controlled testing has little value. What you say was known 40 years ago was likely due to the research Dr. Toole conducted at NRC, not because you or some ghost invented it that you can't name. Or reference.

Anyway, until you start writing clearly, linking to references, and lowering the bar of arrogance oozing out of your posts, there is little you can accomplish.

But his dog is adorable.

 

[Floyd Toole]

Well, with your permission, Dr Guenther Theile published findings on how timbral balance is affected by missing an idenfication of a sound source, lol. I suggested to read that short piece once in a while, it's science. I linked it several times, maybe seven, without *any* reaction? Now you may find it using artificial intelligence under: Guenther Theile superimposed sound field 1980.

Excerpt: the feeling of a balanced sound depends on brain activities that take localisation into accout, in other words, what you "hear" is NOT a mirror of what pysically reaches the ear(s). Not to the least. To put it even another way round, what you think of a tonal balance depends on what you imagine where in space its source may be.

I have not seen your earlier references to Gunther's work - I dip in and out of these forums, mostly out. I spent time with him in Germany. You are referring to his PhD thesis in 1980, in which he references a paper written by me describing results from my PhD thesis in 1965 . He investigated stereo phantom images and summarizes some of his work as: "The aim of the experiment was to prove that the comb filter effect evident at the ears does not influence the sound colour of the phantom source as much as is stipulated by the summing localisation theories". Some of his "association theory" may well apply to certain aspects of perception, but what is now known is that the centre phantom image - the featured artist - is definitely coloured by the comb filtering. The effect is measurable and audible - see Figure 7.2 in the 3rd edition and associated text. It creates a serious dilemma for recording multichannel audio with a real centre channel that is timbrally incompatible with a centre phantom image and comb-filtered images elsewhere on the soundstage. I discuss this in more detail in the upcoming 4th edition. Gunther also proposed diffuse-field calibration of headphones, which is now modified by recent research, as described by Sean Olive in his papers and in the 4th edition. Science moves on.

 

[olieb]

The off-axis sounds are subject to longer propagation path lengths (-6 dB/double distance) and to correspondingly increased air attenuation at frequencies above about 1 kHz. Put the two together, and even an omni, dipole or dipole loudspeaker will show attenuation of the steady-state sound field as a function of frequency.

But if I am not overlooking something, this air attenuation can only contribute a small portion of the HF-attenuation that @Arindal was pointing out.
With 20°C and 50% humidity air attenuation is about 1.6dB/10m at 10kHz and one would need a very big listening room to have direct sound or early reflections to be more attenuated than one or two decibel even at 10kHz. The contribution from off axis sound being tilted down with frequency seems considerably greater for most front firing speakers.
So the question remains, whether the room reflections (early and later) having much less HF-energy and therefore sounding "dull" (as @Arindal was telling about) pose a relevant problem for the perceived sound (quality)? Or is the direct sound so much more important that this is negligible?

This phenomenon is evident when listening in concert halls where the reverberant sound field dominates beyond the first few rows (the critical distance). This reverberant field is massively rolled off at high frequencies, yet well into it the sound remains clear and well balanced.

It is true that an orchestra still sounds "balanced" even in a row further into the hall, but the balance is quite different nevertheless. Sitting in a front row will have the listener be subject to much more HF energy than a more distant seat, it is not the same sound or balance at all, at least that is my experience.
But as was discussed earlier, adaption sets in. Of course the orchestra still sounds "right" even in row 15, how could it not, as one is sitting in front of "the real thing". But there certainly is a lot of context processing by the brain going on.

 

[Floyd Toole]

I can't see why a guy who got a few months or maybe a year(?) of listening training at Harman would be better at hearing tonality problems than a guy who has already been doing it professionally for 10 or 20 years. More training should, in general, mean you get better at it, don't you think?

The Harman listeners were "trained" to hear and identify the frequencies of resonances in multiple-loudspeaker comparison tests. Recording engineers may or may not notice moderate resonances, especially as humans adapt to them, normalizing them, with familiarity. They can benefit from using neutral loudspeakers, but may not be aware of coloration in the ones they work with daily. They should be confident that timbral effects are totally in the art they are creating, not contributed by the loudspeakers. Right?

 

[Heinrich]

You are referring to his PhD thesis in 1980, [he] summarizes some of his work as: "The aim of the experiment was to prove that the comb filter effect evident at the ears does not influence the sound colour of the phantom source as much as is stipulated by the summing localisation theories".

Sure, but I got him a bit differently. that the classic summing theory is incomplete, which is the common stark statement in a phd thesis. To support this he states, besides other, that the sonic impression of sound color changes once a phantom source is identified. He seems to be not much after comb filter, but instead takes the whole Head Relate Transfer Function into account. But I'm not exactly the person to argue on the details.

Some of his "association theory" ...

Ja, ja, the German 'gestalt', a placeholder for everything ;-)

Btw., thank's for your book, eye opener! At least in putting it all on a straight line, what I felt forever to be wrong with and in this business.

...Gunther also proposed diffuse-field calibration of headphones, which is now modified by recent research, as described by Sean Olive in his papers and in the 4th edition. Science moves on.

I'm not that convinced either, but it feels more unsatisfying than plain wrong. It's madening how flexible we get once the music really speaks to us.