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Evidence-based Speaker Designs

Blumlein 88

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What I mean is: supposing there are two headphones: some Sennheiser and some Beats. Reputedly (-I've never heard them) the listener may prefer the Beats, but because they know they are being tested for their preferences for 'hi-fi' (if they have just driven to Harman headquarters, say) they may feel they should prefer the Sennheiser anyway. True test blindness would be difficult to achieve.
Easy solution. Throw in some Stax, and Beyerdynamics or Audeze with the other two.
 

andreasmaaan

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What I mean is: supposing there are two headphones: some Sennheiser and some Beats. Reputedly (-I've never heard them) the listener may prefer the Beats, but because they know they are being tested for their preferences for 'hi-fi' (if they have just driven to Harman headquarters, say) they may feel they should prefer the Sennheiser anyway. True test blindness would be difficult to achieve.

Well that's not science, that's just a survey ;)
 

Cosmik

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I've run into a few people who doubt the moon landing. Never one who thought the earth was flat. Know a couple anti-vaxxers (one because they have an autistic child). I don't think such people are as prevalent as they might seem in the media.
We should have a thread on conspiracy theories. Everyone believes in conspiracy theories, but some are more respectable than others. If you believe that there is such a thing as a D-notice (in the UK) then you automatically acknowledge that there's stuff that doesn't get reported, and at the request of people who have an interest in it not being reported. And can a person in the UK read Private Eye and yet in all honesty sneer at 'conspiracy theorists'?

If you went back 20 years you wouldn't have found much support for the notion that diesel cars were a lot worse for the environment than was being let on - that an entire industry had a vested interest in lying and that governments (or governing bodies such as the EU) were hand in glove with the car manufacturers. This was a 'conspiracy' in plain sight if you chatted to the people at the sharp end in the oil companies. Anyone with a brain (even IQ 100 :)) could see that there was a political motivation (green virtue merits) and a financial motivation (lobbying by German car manufacturers) for governments and industry to 'conspire' together - even if not directly - but people chose to ignore this.
https://www.theguardian.com/environ...e-diesel-in-europe-impact-on-health-pollution
https://www.politico.eu/article/report-german-car-companies-ran-cartel-going-back-to-the-90s/
 

Cosmik

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Well that's not science, that's just a survey ;)
I should have been more clear: the subject doesn't know the brands (he is blind to that), but he already has a preconceived notion of what sounds like 'hi-fi' and so he modifies his 'preference' accordingly to suit the circumstances (being tested by men in white coats at a hi-fi-oriented establishment).
 

andreasmaaan

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I should have been more clear: the subject doesn't know the brands (he is blind to that), but he already has a preconceived notion of what sounds like 'hi-fi' and so he modifies his 'preference' accordingly to suit the circumstances (being tested by men in white coats at a hi-fi-oriented establishment).

Yes good point. In fact I also see this as a legitimate problem, and one reason why I’m less interested in the results of preference studies than in the results of audibility studies.
 

oivavoi

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Interesting thread. It seems like the main criteria on this list is the dispersion pattern of the speaker, or more precisely constant directivity. While I do agree that the dispersion pattern is important, I don't think the psychoacoustic evidence so far suggests that it's the most important factor when it comes to perceived fidelity. In a review article from 2009, Evans et al. couldn't find any clear conclusions in their review of the research:
"Of the majority of studies carried out observing directivity directly,
results have indicated little distinction between types".

This aligns with my own subjective experiences. Having been a firm believer in the importance of constant directivity, those are the speakers that I've sought out, both to audition and to own. But I've slowly realized that the direct sound seems to dominate my perception when I'm sitting in the sweetspot - frequency response, dynamics, lack of annoying distortions etc. When sitting outside the sweetspot, off-axis response and constant directivity obviously becomes important.

According to legendary speaker designer David Smith, this is also in line with the findings from Toole's research at the NRC in Canada:

"I think Toole’s early research shows is that axial frequency response is the number one criterion. Power response, or overall directivity, seems to be a poor correlation with subjective impression. Why this is important is because it shows how room curves (strongly influenced by later arriving off axis response) can be misleading. The larger the room the more power response determines the room curve and the more misleading they will be".

Now I'm the first to point out that there are many limitations with the body of work known as psychoacoustic loudspeaker research. There are probably more people doing research at the social science department at my university than the total number of people doing research into high-fidelity loudspeakers worldwide. So there is something to be said for common sense - just making the speakers and the system do their job - reproducing the signal as faithfully as possible (which would mean active crossovers, no vinyl or valves, etc).

But at the moment, I don't think there's enough evidence to point out constant directivity designs as inherently more "evidence-based" than others. Sure, everything else being equal, constant directivity is better than non-constant directivity. But there may be trade-offs. A horn may make the directivity more constant. But if it introduces colorations or HOMs in the direct sound, is it then preferable over a direct radiator with more uneven directivity, but a less colored direct sound? I'm not so sure.
 

SIY

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How about this.. tell me why are Khardasians so rich? What quality goods are they selling to average Joe?

Khardasian Pere is (or was, no idea if he's alive) a very prominent LA attorney. The younger ones provide entertainment. Whether people hate them or not is not relevant- they are entertained by them, just like by any other performer, including football players and other TV stars.

(disclaimer: I am not a TV person so wouldn't recognize a Khardasian if I saw one)

To that point, Nelson Pass said something to me that was maybe one of the most profound and clarifying things I've ever heard: "High end audio is the entertainment business." And he was not talking about the music.
 

andreasmaaan

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"But at the moment, I don't think there's enough evidence to point out constant directivity designs as inherently more "evidence-based" than others. Sure, everything else being equal, constant directivity is better than non-constant directivity. But there may be trade-offs. A horn may make the directivity more constant. But if it introduces colorations or HOMs in the direct sound, is it then preferable over a direct radiator with more uneven directivity, but a less colored direct sound? I'm not so sure."

I'm not sure I share quite share your interpretation of Dr Toole's research here (perhaps @Floyd Toole himself would care to weigh in). It's been a while since I read up on this, but IIRC, a well-controlled but downward-sloping power response tended to be preferred - at least to a similar extent to constant directivity, if not slightly more so.

Otherwise 100% agree with your post.
 

oivavoi

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I'm not sure I share quite share your interpretation of Dr Toole's research here (perhaps @Floyd Toole himself would care to weigh in). It's been a while since I read up on this, but IIRC, a well-controlled but downward-sloping power response tended to be preferred - at least to a similar extent to constant directivity, if not slightly more so.

Otherwise 100% agree with your post.

Yes, that was David Smith's interpretation, not mine - and he explicitly says in the rest of the quote (that I didn't include) that he thinks dr. @Floyd Toole moved towards emphasizing room curves later on, in spite of the findings from his early NRC studies.

But I do think dr. Toole has beeen indicating here on the forum that room curves are not the most important thing in itself - that they rather are a function of a well-performing speaker? Which would roughly mean that "a well-performing speaker a decent room curve makes", but that "retro-fitting a decent room curve doesn't a well-performing speaker make". Better to let the Dr. explain it himself! :)

What I do think one can see from both dr. Toole's research and other studies, is that a wide directivity is often preferred by many listeners - as it increases envelopment etc, and this is often perceived as more important than razor sharp stereo imaging. I tend to agree with @Cosmik that the directivity pattern of the loudspeaker is the one area in sound reproduction where there's no "right" answer as to what fidelity would entail.
 

andreasmaaan

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Yes, that was David Smith's interpretation, not mine - and he explicitly says in the rest of the quote (that I didn't include) that he thinks dr. @Floyd Toole moved towards emphasizing room curves later on, in spite of the findings from his early NRC studies.

But I do think dr. Toole has beeen indicating here on the forum that room curves are not the most important thing in itself - that they rather are a function of a well-performing speaker? Which would roughly mean that "a well-performing speaker a decent room curve makes", but that "retro-fitting a decent room curve doesn't a well-performing speaker make". Better to let the Dr. explain it himself! :)

What I do think one can see from both dr. Toole's research and other studies, is that a wide directivity is often preferred by many listeners - as it increases envelopment etc, and this is often perceived as more important than razor sharp stereo imaging. I tend to agree with @Cosmik that the directivity pattern of the loudspeaker is the one area in sound reproduction where there's no "right" answer as to what fidelity would entail.

Actually, I wasn't trying to make any kind of comment on the question of room curves. I was just interested in the directivity aspect of Smith's quote. Directivity of course influences the in-room response but is not the same thing. My understanding of the Toole research was that a downward-sloping power response (or upward sloping directivity index if you prefer to think in those terms) was at least as popular - if not preferred - over constant directivity.

I also would have said @Cosmik has the opposite view! I.e. that constant directivity is the only correct way (not a view I share, but he makes a persuasive case IMO).
 

Krunok

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I've wondered the same thing. Modern DACs are far and away the best performing part of the whole reproduction chain. I put up 8th generation ad/da copies that people couldn't pick vs originals using two bits of gear that cost about $350 each.

I think it is the same reason Amir tests so many DACs. They are small, easily shipped, have a very defined role, and that makes trying them out easy. Swapping out big amplifiers is much more trouble than DACs as is shipping them around and measuring them. Speakers are even worse. Heaphones are easy of course.

Clearly transducers whether phones or speakers are where really big differences lie and worth considering. At least for this forum Amir isn't even in a position to test those meaningfully.

So I don't have a good answer for your question on that. I would say it doesn't seem to be just an average Joe problem.

You're right, it would really be difficult for Amir to make tests of amplifiers for the reasons you've mentioned and speakers are even more complicated logistic wyse. However, what is average Joe's problem is the obsession with DACs and belief that changing DAC would improve SQ.
 

Krunok

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I think you can generalize this under "drama-soaps". I think it might have to do with intrinsic jealousy or desire to be able to have what the rich have. First, one stays for controversy and gets hooked on the drama for it's entertainment.

Isn't this why most people watch tv?

I think that "intrinsic jealousy or desire to be able to have what rrich people have" is one of typical characteristics of average Joe and Jane. People with more developed persoanility aren't jealous of Meghan Markle and don't have such desires.

One more thing - I think that most folks don't really understand what kind of life she has now. She's practically lost all of her personal freedom as she's heavilly bounded by royal procols. She got th money, true, but she cannot spend it the way she would want. And yeah, she's also forced to wear funny hats with feathers so all the peacocks in Buckingham palace courtyard envy her. :p
 

Krunok

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Khardasian Pere is (or was, no idea if he's alive) a very prominent LA attorney. The younger ones provide entertainment. Whether people hate them or not is not relevant- they are entertained by them, just like by any other performer, including football players and other TV stars.

Sure they are entertained. IMO, what entertains you is saying much about you.

To that point, Nelson Pass said something to me that was maybe one of the most profound and clarifying things I've ever heard: "High end audio is the entertainment business." And he was not talking about the music.

Was he talking about high end audio equipment and joy of possessing such equipment per se?
 

SIY

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Was he talking about high end audio equipment and joy of possessing such equipment per se?

Yes, possessing, dreaming about, reading about, talking about, fantasizing about... At the time of our conversation, the highest grossing company in high end audio was Stereophile.

"If I could just get those Imperator 667s, it would sound so great I could finally get laid!"
 

Krunok

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Yes, possessing, dreaming about, reading about, talking about, fantasizing about... At the time of our conversation, the highest grossing company in high end audio was Stereophile.

"If I could just get those Imperator 667s, it would sound so great I could finally get laid!"

LOOL :D :D :D
 
OP
Ilkless

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But at the moment, I don't think there's enough evidence to point out constant directivity designs as inherently more "evidence-based" than others. Sure, everything else being equal, constant directivity is better than non-constant directivity. But there may be trade-offs. A horn may make the directivity more constant. But if it introduces colorations or HOMs in the direct sound, is it then preferable over a direct radiator with more uneven directivity, but a less colored direct sound? I'm not so sure.

My starting point on directivity was never "preference". It is - to quote Geddes - a definable "accuracy" that entirely avoids the arbitrary. From then on this thread became a survey of the various rationally-defensible approaches at constant directivity, constrained by applications (eg. placement, listening distance, area of coverage) and tolerance for tradeoffs (as in the horn vs HOM example, or vertical lobing) in service of optimising to these applications.
 

oivavoi

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I also would have said @Cosmik has the opposite view! I.e. that constant directivity is the only correct way (not a view I share, but he makes a persuasive case IMO).

Just like dr. Toole, @Cosmik should be allowed to explain his own views... :) But what I meant with "directivity pattern" was rather whether it should be wide or narrow or omni. On this, I don't think there's a "right" answer. I'm aware that Cosmik thinks directivity should be constant, no matter if it's wide or narrow!

Intuitively and rationally, it does make sense that constant directivity is the way to go. And as I said, there is no reason not to have it, if you can easily have it. The question rather becomes if the trade-off that is needed in order to achieve this is worth it, in a given implementation.
 

Ron Texas

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Many class D amplifiers with switching power supplies are not that big or heavy. More expensive than DAC's to ship, but nothing like amplifiers with big transformers or large heat sinks.
 

Krunok

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Many class D amplifiers with switching power supplies are not that big or heavy. More expensive than DAC's to ship, but nothing like amplifiers with big transformers or large heat sinks.

True. And in practical terms they have the same sound neutrality as DACs. :D

Of course, not all of them are built the same, but when you see how @March Audio built his excellent products with Lego bricks available on the market I guess the transducers remain the only true challenge in the audio equipment arena battle field.
 

Ron Texas

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True. And in practical terms they have the same sound neutrality as DACs. :D

Of course, not all of them are built the same, but when you see how @March Audio built his excellent products with Lego bricks available on the market I guess the transducers remain the only true challenge in the audio equipment arena battle field.

The "Lego" approach is being used by Nord. There are now single board Hypex and Icepower amplifiers. That means power supply and a stereo amp on one board. Just put it in a box. The only drawback is low input sensitivity where 2.35V is needed to reach 200 watts. Anyone know of a good cheap preamp?
 
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