Modern Measurement Tools Are Tricking Audiophiles Into Trusting Bad Data, Warns Veteran Speaker Designer

[a4eaudio]

Just noticed that @a4eaudio beat me to it.

I didn't really beat you to it, I just posted a picture. You explained why.

 

[MattHooper]

? I mean, which research of the last 15 years (since competitive constant directivity speakers are available as potential A/B test rivals) has underlined the theory that colorated reverb is preferable over linear reverb tonality?

Could you clarify for me what you mean by those two terms that I have bolded in your response?

Thanks.

 

[kyuu]

Could you clarify for me what you mean by those two terms that I have bolded in your response?

Thanks.

I believe they are referring to constant directivity as being "linear reverb", and anything that isn't constant directivity is therefore "colored reverb". AFAIK, the research we have shows a clear preference for smooth directivity, usually gradually decreasing. I'm not aware of any that shows a preference for constant directivity, although that would certainly fall under the definition of smooth.

 

[tmtomh]

I believe they are referring to constant directivity as being "linear reverb", and anything that isn't constant directivity is therefore "colored reverb". AFAIK, the research we have shows a clear preference for smooth directivity, usually gradually decreasing. I'm not aware of any that shows a preference for constant directivity, although that would certainly fall under the definition of smooth.

Yes, that's the argument Arindal is making here (and in several other threads).

 

[Newman]

I believe they are referring to constant directivity as being "linear reverb", and anything that isn't constant directivity is therefore "colored reverb".

That was my assumption too.

AFAIK, the research we have shows a clear preference for smooth directivity, usually gradually decreasing. I'm not aware of any that shows a preference for constant directivity, although that would certainly fall under the definition of smooth.

I have gotten the impression that it is uncertain, but inclined more the other way, ie, for stereo or mono playback, constant directivity is the objective and definitely hits good preference ratings, but a smoothly rising directivity (with rising frequency) is possibly just as highly rated.

"Directivity, per se, is not a major "sound quality" issue, but something that interacts with one's impression of stereo listening, where there seems to be endless effort to find a loudspeaker that can make directionally and spatially deprived stereo deliver something it is incapable of." Toole

"...about the directivity and how it affects soundstage and imaging. Since both of these are strongly influenced by recordings, and some amount of personal preference is involved, there are no hard rules about directivity except that changes as a function of frequency should be gradual. Constant directivity is an unachievable goal with most practical loudspeakers as they all revert to omni at low frequencies. The most constant above crossover tend to be horns, but I know of no evidence that this characteristic is a benefit over well designed cone and dome systems." Toole

"As my earliest JAES (1985-86) papers showed, listeners in double-blind evaluations preferred loudspeakers with flat and smoothish on-axis (direct sound) frequency responses. Beyond that, those that were preferred exhibited the smoothest off-axis (reflected sound) responses. None of those loudspeakers were horns, so the DI varied with frequency. Now that we have loudspeakers with excellent constant directivity horns, it is seen that these too receive elevated sound quality ratings (see the cover of my book). I don't know that we have sufficient data to be able to define the tolerances on variability in directivity, but it seems fairly obvious that smooth gradual changes would be preferable to uneven, changes - aiming for reasonable timbral matching of direct and reflected sounds - remember that the reflecting surfaces can modify the spectra of reflected sounds." Toole

For MCH playback the directivity behaviour is less critical to preference.

hope this helps, cheers

 

[Suono]

except that changes in the frequency function should be gradual…

This step is crucial, the speaker should be a musical instrument or whatever is being photographed by the microphone

 

[kyuu]

I have gotten the impression that it is uncertain, but inclined more the other way, ie, for stereo or mono playback, constant directivity is the objective and definitely hits good preference ratings, but a smoothly rising directivity (with rising frequency) is possibly just as highly rated.

Sorry, I meant increasing. I was thinking the wrong way around, with "decreasing" meaning the dispersion gets smaller.

 

[Arindal]

We have vastly moved the needle with respect to importance of measurements in the entire spectrum of audio products.

Would say in your own ´peer group´ and among people who had been siding with tech-spec-marketing hi-fi for several decades (who were kind of silenced by the success of implausible high end claims in the 1990s and 2000s), that has been influential without any doubt. If it inspired people to verifying their audio beliefs and walking away from implausible claims, excellent! Don't want to downplay it.

@tmtomh My comment about decreasing importance of measurements was rather related to products which are sold in mass quantities, shaping the preferences of younger generations (including Z and millennials). In the last 15 years, since Beats was successfully selling headphones with crazy bass boost, and JBL made boomy boomboxes popular, seemingly a lot of companies have followed that path of using effect-laden, colorated sound to boost sales, and I don't see much of an impact of the countermovement among younger folks. A majority doesn't care for measurements at all.

It is a bit of an irony that Harman brands have been at the forefront of this movement, although they had the research capacity to know better from technical point. Obviously sales figures were not on the same page.

for stereo or mono playback, constant directivity is the objective and definitely hits good preference ratings, but a smoothly rising directivity (with rising frequency) is possibly just as highly rated.

That was my point, yes. If a mild decrease in indirect sound level towards higher frequencies is not contributing to audibly dull reverb - which can be achieved under lab or studio conditions, if D.I. increase is not as steep or outside the distinguishable frequency bands - I don't necessarily see a problem in that, and I am not going to tell people to which products they should listen to. I just dare to call it colorated, particularly in case reports are surfacing saying that certain perfect linear (on-axis) speakers sound dull or lame.

AFAIK, the research we have shows a clear preference for smooth directivity, usually gradually decreasing.

I am not aware of such research being publicly available. I asked Dr. Toole if such experiment ´constant vs. decreasing D.I.´ as the only decisive factor had been conducted under his supervision, but the answer was rather vague, or hinted at experiments which had compared vastly different, commercially available products with tonal tendency of directivity being not the major difference.

Have taken part and was aware of controlled experiments which tried to isolate directivity as the single difference, and the results were pretty much in favor of constant (which was surprising to me initially). This is in line with what people like Linkwitz, Jones, Wolf, Putzeys, Kiesler, Geddes have postulated.

Again, I am not telling people what is right or wrong. I am trying to discuss potential explanation for the reports of dull tonality, and I encourage everyone to make own experiments.

 

[amirm]

And do you think that designers who create speakers like the TadR1 or, for example, the Magico, don't have mathematicians, physicists, or neurobiologists who, in addition to using it, can't understand it?

They may have people with math or physics background depending on which company we are talking about. But even so, having such degrees does not mean know anything about underlying mathematics and operation of Klippel NFS. Such knowledge is not required for design of speakers. Or ordinary measurements that are gated, outdoor or anechoic. Even using Klippel NFS doesn't require such knowledge although it is better if one knows.

I think no one can know more than those who dedicate themselves to making speakers every day.

Of course they can. This field can be extremely broad. Being good at one part doesn't mean you know everything. You can design speakers all day long without more knowledge than a technician. To wit, many people DIY speakers with no prior engineering knowledge let alone mathematics or physics.

Unless you can point to actual documentation of Andrew's expertise in acoustic signal processing, I suggest you stop arguing with words.

 

[Toni Mas]

And do you think that designers who create speakers like the TadR1 or, for example, the Magico, don't have mathematicians, physicists, or neurobiologists who, in addition to using it, can't understand it? Andrew Jones studied physics and mathematics and specialized in audio. He knows exactly what a speaker needs to do, like Kef tad elac. I think no one can know more than those who dedicate themselves to making speakers every day.

Well, I think that the mere fact of having been in the market for years designing and selling speakers should give you some creds, even if your products do not match the taste of everybody, nor match the criteria of all experts or reviewers, self erected owners of an absolute truth which is still to be found while speakers remain the weakest leak in the audio chain ...

 

[Suono]

Again, I am not telling people what is right or wrong. I am trying to discuss potential explanation for the reports of dull tonality, and I encourage everyone to make own experiments.

The speaker's tone doesn't need to be dampened, and the room itself needs to be "damped." If my daughter plays in my listening room, the violin sounds better than in her room. It's still the same violin, but it sounds better in my room.

 

[Heinrich]

..., for stereo or mono playback, constant directivity is the objective and definitely hits good preference ratings, but a smoothly rising directivity (with rising frequency) is possibly just as highly rated.

You are quoting Toole, and here are the actual statements. Essentially, it says that the topic of DI still needs to be clarified. @Arindal requested in a post that proof be provided for a preference for colorations – as if his purely speculative statement had to be disproven by skeptics, instead of him, as its originator, proving its validity.

... which research of the last 15 years (since competitive constant directivity speakers are available as potential A/B test rivals) has underlined the theory that colorated reverb is preferable over linear reverb tonality?

So this is all a bit strange and hardly has my attention anymore. And again, I have a side note. A constant directivity can exist – namely, when a relatively small speaker is built into a filled shelf or completely into a wall. It sounds thin, bare with me, see below.

****
My strongest objection – and this may also be directed toward Toole – is that the timbre is determined in the recording studio and reproduced at home – or not. It’s important to understand that this timbre is subject to the arbitrary choices of the mixer; it is 'created' in the best sense. It is not an automatic 1:1 representation of some original. Unfortunately, that is always forgotten – and the stubborn neglect becomes a bit annoying.

The timbre is determined by the mixing engineer based on their personal taste judgment. To do that, of course, they have to listen to the mix – through their speakers. These have certain characteristics, as does their listening room.

So now, what does the consumer at home actually want, given that all of this has already happened and can’t be changed? Where is their preference supposed to come from, and how would it be justified?

I’d really like to hear a well-thought-out answer to that (I know mine). It’s extremely strange when people speculate in a freestyle manner about the most remote details, yet don’t spare a single thought for the most immediate basics.

 

[Suono]

Unless you can point to actual documentation of Andrew's expertise in acoustic signal processing, I suggest you stop arguing with words

Andrew Jones's material, knowledge, and studies will not be available to anyone. If you compare DIY speaker builders to a Tadr1, I recommend you listen to them.

 

[Toni Mas]

You are quoting Toole, and here are the actual statements. Essentially, it says that the topic of DI still needs to be clarified. @Arindal requested in a post that proof be provided for a preference for colorations – as if his purely speculative statement had to be disproven by skeptics, instead of him, as its originator, proving its validity.

So this is all a bit strange and hardly has my attention anymore. And again, I have a side note. A constant directivity can exist – namely, when a relatively small speaker is built into a filled shelf or completely into a wall. It sounds thin, bare with me, see below.

****
My strongest objection – and this may also be directed toward Toole – is that the timbre is determined in the recording studio and reproduced at home – or not. It’s important to understand that this timbre is subject to the arbitrary choices of the mixer; it is 'created' in the best sense. It is not an automatic 1:1 representation of some original. Unfortunately, that is always forgotten – and the stubborn neglect becomes a bit annoying.

The timbre is determined by the mixing engineer based on their personal taste judgment. To do that, of course, they have to listen to the mix – through their speakers. These have certain characteristics, as does their listening room.

So now, what does the consumer at home actually want, given that all of this has already happened and can’t be changed? Where is their preference supposed to come from, and how would it be justified?

I’d really like to hear a well-thought-out answer to that (I know mine). It’s extremely strange when people speculate in a freestyle manner about the most remote details, yet don’t spare a single thought for the most immediate basics.

So what should we ask for when choosing a loudspeaker? That It sounds the same in your room as it sounded to the mixing engineer using different speakers in a different room? Is this what is called a neutral sounding speaker? The shortest path should then be using the same speakers in a room as similar as possible... And have the same taste as this engineer...

What if the gear used by that engineer is not as neutral as politically correct current state of the art criteria require? Or, more than an art, is there any scientific way of mixing?

 

[Sokel]

Just a note, AJ does not only built speakers but their drivers too.
The Mofi's coaxial for example was no simple task, even for the people who made the mass production of it.

 

[thewas]

That is exactly the problem with NFS in my understanding, that it tries via iteration, to calculate a number of imaginary sound sources at unknown positions, which would fit to the soundfield it has actually measured at numerous positions in what is neither nearfield nor farfield. If the actual number of sound sources is closer to indefinite, they are far away from each other compared to the wavelength, or their phase relations towards each other are chaotic, that cannot be as accurate as claimed, as some measurements with bending-wave planar transducers or cardioids have proven.

Can you please post such examples?

 

[JSmith]

I have the advantage of having worked with truly anechoic measurements of existing loudspeakers for decades, manyfold the number of what Amir has measured, as well as with Klippel systems, so I had the chance to compare.

BTW, who are you? Do you work for the industry? Are you an Arindal employee?

No, have never worked in the speaker industry, and I am not even aware that a company of that name exists, so: no.

None of this adds up... so you've tested thousands of speakers in anechoic chambers and with Klippel NFS, yet do not work in the audio industry and have never heard of Arendal Sound who have been around for 10+ years?

I note two speaker manufacturers follow your profile here too. I think some clarification is needed here... there are strict rules at ASR regarding audio dealers, manufacturers and members with a commercial interest, as per below;

Rules for Audio Dealers, Manufacturers, Members with Commercial Interest. This includes any Guest Contributors/Reviewer with Commercial endorsement

Audio Science Review Rules for Dealers, Manufacturers, Reviewers and Members of Industry. We encourage participation from members of industry in the forum. So please feel welcome here. We expect you to post with highest levels of professionalism. You are representing an industry and it is...

www.audiosciencereview.com

JSmith

 

[Heinrich]

Just a note, AJ does not only built speakers but their drivers too.
The Mofi's coaxial for example was no simple task, even for the people who made the mass production of it.

I'm pretty much sure Andrew Jones is a good guy, whatever that means, and the article misrepresents him--maybe even by intent.

So what should we ask for when choosing a loudspeaker? That It sounds the same in your room as it sounded to the mixing engineer using different speakers in a different room? Is this what is called a neutral sounding speaker? The shortest path should then be using the same speakers in a room as similar as possible... And have the same taste as this engineer...

What if the gear used by that engineer is not as neutral as politically correct current state of the art criteria require? Or, more than an art, is there as scientific way of mixing?

Exactly, good you ask back. This is all not clarified yet. To obssesively discuss DI in minute detail is that unhealthy focus on misunderstood measurements, that the article is somehow addressing in its latter part. Not the data is wrong, but how people read it (and talk about a lot).

In all brevity: mixer judges and crafts the record over their speakers A in room X w/ listening position P until it "sounds good" to them. It is shipped to the consumer to be played for fun (needless to say?). What are the listener's intentions, actually? To replicate the experience of the mixer, then also speaker A and room X shall be used, listening position P again. Maybe there is a speaker B and a room Y, listening position L that compensate each other to give the same result as A, X, P combined. That's an inevitable case as long as the listener is not joining the studio.

Would the spin help to find B, Y, L? Just to give an example: narrow directivity in B compensates lively room Y, position L eq/ P still. Questionable.

The listener "regular Joe" may accept to depart from the given route w/ compromises and choses some arbitrary combination C, Z, M--that's a common case. Z and M are not under control of audio dogma for (very) good reasons.

Note: preference ratings derived under controlled conditions in rooms resembling X and at position P cannot (in)validate the fit of speaker C to Z, M using reference material/recordings made under conditions A, X, P (the mixer's choice). The methodology simply doesn't apply.

Toole says, and I hope I get it right, the most relevant part is A, and only so far as A doesn't imply interaction with room X at position P. In short, directivity, responsible for room and position, is of secondary interest. This is true and practical at the same time, learn to accept the good. A and C can be compared for preference under conditions X, P and that holds even if C is used under conditions Z, M. At least to a sufficient degree, even if directivity is left as a secondary concern..

Just a personal 'note' Tl;dR, I know

 

[RexrothPigeon]

mixer judges and crafts the record over their speakers A in room X w/ listening position P until it "sounds good" to them.

Between mix engineer & consumer is a mastering engineer, whose job is to prepare the final audio mix for distribution by ensuring that it sounds good on various playback systems, streaming services, cd, vinyl, etc. The skilled mastering engineer optimizes for translation across as many possible listening conditions as possible.

 

[007Shorty]

Has anyone ever tested how big the difference is in spinorama measurements with a microphone distance of 1 and 3 meters (approximately 3 and 9 feet)?

That's the point that puzzles me most in Andrew Jones' report.