Preference vs. audibility - please keep them separate.

[RogerD]

If only God had blessed audiophiles with better ears....

 

[Phelonious Ponk]

TacT implemented that in their room eq products. And yes, it was in digital domain.

This is the deliberate and strategic use of psychoacoustics (or an understandiing of ear/brain function) in audio electronics design. Tact is definitely high-end. There's one example. Any more?

Tim

 

[jkeny]

I think it might be useful at this point to re-visit where this line of conversation began...
Atmasphere was clearly (to me, anyway) talking about a top-down approach; understanding the way the ear/brain system works and using it to enhance the illusion. This is a deliberate, strategic approach. What you're talking about seems to be simply designing well and getting a psychoacoustic effect as a result. Is the result equally valid? Sure, if it happens to be equally effective. But we'll have to disagree that the approach is equally valid. One counts on knowledge of psychoacoustic effects that are deliberately, strategically leveraged. The other counts on lucky accidents.

Tim

Tim, I think you are missing the point - if we knew all there is to know about psychoacoustics, then you might have a point - theory directly leading to audible results.
But we don't which I believe Atmasphere is also saying?

 

[jkeny]

This is the deliberate and strategic use of psychoacoustics (or an understandiing of ear/brain function) in audio electronics design. Tact is definitely high-end. There's one example. Any more?

Tim

I gave you Meriden' apodising filter example!

 

[Phelonious Ponk]

That's not true at all and you know it. You have a pattern of posting your opinions and asking others to do your research to prove your point which I find hilarious while Micro is not so amused. Your tactic has been commented on numerous times on numerous threads.

There is a group of members here who make what I think are pretty wild, unsubstantiated claims that amount to wish-fullfillment on the part of hobbyists and BS on the part of designers/manufacturers. I find that asking questions is a much gentler and more polite way to challenge those claims than shaking my finger at them. I do hope they will answer those questions. I don't expect to have to disprove their claims, as they are their claims, not mine. The current example is micro's assertion that Lamm and Pass design with psychoacoustics in mind and have talked about it on the internet in many interviews. The first one I found, less than a year old, contradicted that assertion. His assertion, not mine. If you think it is unreasonable or unfair of me to expect him to support his assertion; that asking for that support makes it my point to prove, well, we'll just have to disagree again. We should be pretty good at it by now.

Tim

 

[Phelonious Ponk]

I gave you Meriden' apodising filter example!

Thank you. But is an apodizing filter not eliminating pre-ringing, which is a very real distortion, not a psychoacoustic effect? That's a genuine question, by the way. it may impact perception as well, in some way I don't understand.

Tim

 

[RogerD]

This is the closest piece of gear I have seen,it is digital.My circuit is passive but requires 2 small sets of speakers. Enhanced stereo is the future for those who can take the next step.

http://www.lyngdorf.com/products/processors

http://dagogo.com/lyngdorf-rp-1-roomperfect-room-correction-device-review

 

[microstrip]

My apologies if I misunderstood you, but I'd swear you said Lamm was designing amps using psycho acoustic principles to deliberately leverage human perception in audio reproduction, and that I would find him talking about this in interviews online. The very first interview I found, and a very recent one at that, contradicted that position, as Lamm very specifically positioned this use of psychoacoustics in amp design in the future tense.

As I understood it, your expert testimony does not support your argument.

Tim

All documents are easily accessible (as the translations from russian and croatian are not certified by an authority you trust, you can look at the originals) :
http://www.lammindustries.com/interviews.html

I will just quote two sentences for example (both interviews are more than 10 years old)

VL First, I kept asking the so-called simple and naive questions. For instance, we have three amplifiers: one with a 1-2% distortion, another with a 0.1% distortion and yet another with a 0.001% distortion. All three are heard through a speaker with, let's say, about 5% of its own distortion. Theoretically, we shouldn't hear the difference, just a "signature" of the speaker. But the paradox is that we hear the difference between these three amplifiers perfectly. The answer to this question is not that easy: it took me a few years to understand the nature of this effect. There is no place where you can learn how to make the sound--you can confirm this with any serious audio designer, or just any designer who has been able to create a reasonably wellsounding system. I repeat again that I have been learning all my life. I had an opportunity to conduct an enormous number of experiments or, in other words, check my theoretical hypotheses and calculations and narrow the number of topologies capable of producing good sound until I obtained the desired results. As strange as it may sound, a big help in getting the results was my eight-year-long wait in the Ukraine for an exit visa, although this period was full of problems related to my status of a "refusenik" (persecution by the police and other problems). I had time to sort out a lot of ideas and results. Based on the electronic modeling of a human hearing mechanism and having arrived at a limited number of electronic topologies that describe our hearing perception to a greater or lesser degree, I created a number of working prototypes.


Qestion Can you describe the essence of your approach to designing hi-fi equipment?

VL I am a scientist, not only an engineer. I developed electro-mechanical models which describe the hearing mechanism of the human ear. I use these models when I design equipment. I never do listening tests because I already know how it will sound. (End of quote)

I hope that you consider that studying models of human hearing for amplifier development is psychoacoustics ...

 

[Atmasphere]

Ralph-I hate to play the devil's advocate, but I'm going to. I have noticed over the years that many of your upgrades to your product line tout vanishingly lower distortion levels than the version that preceded your newest incarnation of the product. So are you saying there other distortions present in addition to the ones you know about and measure and find ways to lower that you don't know how to measure?

No, I am not saying that at all. What I was saying in the post that you are referring to is that when you run loop feedback, you cannot predict what the actual distortion level of the musical reproduction based on steady state signals.

We don't run feedback in most of our designs so its likely that we don't make as much distortion with constantly changing waveforms as some other designs but there is no good measurement for that so for the time being it will have to remain as conjecture.

Chaos Theory (see http://en.wikipedia.org/wiki/Chaos_theory) suggests that loop negative feedback destabilizes audio circuits (the formula for feedback is the same as a classic Chaotic system). This results in 'bifurcation' which we audiophiles call 'distortion'. Norman Crowhurst graphed the Strange Attractor some years before the branch of science was actually recognized. I can go into this in greater depth but it might be a topic for another thread.

I'm very sceptical of such ideas. Yes, it may sometimes help with (an illusion of?) ambience with some recordings, but may completely mess up others. If there is something to the idea, why not 'formalise' it and do it with DSP, multichannel audio, supplementary surround speakers etc.? The High End way of experimenting with rear firing drivers or whatever looks like trying to solve a many-dimensioned problem by chance using the approved analogue methods, then dressing it up retrospectively as scientific.

I understand the skepticism; once upon a time I held the same view. It really does not matter the recording, and FWIW, this approach is not used to "...help with (an illusion of?) ambience with some recordings"! I had the same misunderstanding. It is used to improve soundstage palpability. That is something very different.

What the ear/brain system does is when a sound is detected, the brain makes a copy and looks for other examples that might show up. It uses the later examples as location information.

 

[microstrip]

(...) What the ear/brain system does is when a sound is detected, the brain makes a copy and looks for other examples that might show up. It uses the later examples as location information.

People should remember this aspect when they want to debate the depth and height information in stereo. It is all an illusion, and the "weakness" of our hearing helps on it, however strange it can seem.

 

[jkeny]

Thank you. But is an apodizing filter not eliminating pre-ringing, which is a very real distortion, not a psychoacoustic effect? That's a genuine question, by the way. it may impact perception as well, in some way I don't understand.

Tim

I don't really follow your question. The decision to use a linear phase filter Vs a minimum phase filter is a consideration based on a consideration of psychoacoustics, no? Which is more audibly significant - constant group delay at all frequencies with pre-ringing or ignoring group delay & minimising pre-ringing?

 

[jkeny]

Tim,
Maxxbass was another example (admittedly not high-end) of using psychoacoustics - in this case using the phantom fundamental phenomena by boosting parts of the freq spectrum to try to provide the illusion that a speaker can produce a bass fundamental frequency that it is physically impossible of actually achieving

 

[Phelonious Ponk]

I don't really follow your question. The decision to use a linear phase filter Vs a minimum phase filter is a consideration based on a consideration of psychoacoustics, no? Which is more audibly significant - constant group delay at all frequencies with pre-ringing or ignoring group delay & minimising pre-ringing?

Yes. I get your point. Thanks.

Tim

 

[Phelonious Ponk]

All documents are easily accessible (as the translations from russian and croatian are not certified by an authority you trust, you can look at the originals) :
http://www.lammindustries.com/interviews.html

I will just quote two sentences for example (both interviews are more than 10 years old)

VL First, I kept asking the so-called simple and naive questions. For instance, we have three amplifiers: one with a 1-2% distortion, another with a 0.1% distortion and yet another with a 0.001% distortion. All three are heard through a speaker with, let's say, about 5% of its own distortion. Theoretically, we shouldn't hear the difference, just a "signature" of the speaker. But the paradox is that we hear the difference between these three amplifiers perfectly. The answer to this question is not that easy: it took me a few years to understand the nature of this effect. There is no place where you can learn how to make the sound--you can confirm this with any serious audio designer, or just any designer who has been able to create a reasonably wellsounding system. I repeat again that I have been learning all my life. I had an opportunity to conduct an enormous number of experiments or, in other words, check my theoretical hypotheses and calculations and narrow the number of topologies capable of producing good sound until I obtained the desired results. As strange as it may sound, a big help in getting the results was my eight-year-long wait in the Ukraine for an exit visa, although this period was full of problems related to my status of a "refusenik" (persecution by the police and other problems). I had time to sort out a lot of ideas and results. Based on the electronic modeling of a human hearing mechanism and having arrived at a limited number of electronic topologies that describe our hearing perception to a greater or lesser degree, I created a number of working prototypes.


Qestion Can you describe the essence of your approach to designing hi-fi equipment?

VL I am a scientist, not only an engineer. I developed electro-mechanical models which describe the hearing mechanism of the human ear. I use these models when I design equipment. I never do listening tests because I already know how it will sound. (End of quote)

I hope that you consider that studying models of human hearing for amplifier development is psychoacoustics ...

I do, if that study impacts the amplifier design in a tangilbe way (which is not clear here), though I find all this pretty vague, especially when compared to some of the cleary psycyoacoustic effects that have been explored in the HT and digital realms. And it's interesting that ten years later he seemed to think this sort of research was in the future. A bad translation perhaps.

Tim

 

[Atmasphere]

Who,what,where....an example of a speaker incorporating psychacoustics specifically.

Loudspeakers made by Audiokinesis (Duke LeJeurne). He showed a speaker at the RMAF that employed a 'splash module' which was a full-range loudspeaker behind the main speaker that laid on its back and fired upwards. They had a switch so you could turn it on and off. The splash ambiance created a more detailed, palpable soundstage. It was easy enough to hear, not sure how you would measure something like that.

I would also look at Earl Geddes.

 

[Phelonious Ponk]

Loudspeakers made by Audiokinesis (Duke LeJeurne). He showed a speaker at the RMAF that employed a 'splash module' which was a full-range loudspeaker behind the main speaker that laid on its back and fired upwards. They had a switch so you could turn it on and off. The splash ambiance created a more detailed, palpable soundstage. It was easy enough to hear, not sure how you would measure something like that.

I would also look at Earl Geddes.

...and Sigfreid Linkwitz. And to lesser, but similar effect, any speaker with unusually wide, linear response. But broader, deeper, more immersiive, yes. More detailed? I'm not so sure.

Isn't Geddes the opposite effect? Controlled directivity?

Tim

 

[RogerD]

Loudspeakers made by Audiokinesis (Duke LeJeurne). He showed a speaker at the RMAF that employed a 'splash module' which was a full-range loudspeaker behind the main speaker that laid on its back and fired upwards. They had a switch so you could turn it on and off. The splash ambiance created a more detailed, palpable soundstage. It was easy enough to hear, not sure how you would measure something like that.

I would also look at Earl Geddes.

So it was just a third speaker used full range firing upwards. That doesn't fit what few others have done in enhanced speaker configs. Hazard Reeves back in the 50's used a 6 speaker array...LR,outboard LR,and center LR,same as mine,but my enhancement speakers are filtered.

 

[microstrip]

I can also add an interview in the 90s with the late Biil Johnson where he addressed measurements and listening carried during development of Audio Research products. He clearly sated that the classic static measurements were insufficient, and that ARC had developed some correlations between alternative methods with the help of listening. He was very specific showing that ARC was no more a one man company, but they had a good number of talented engineers, with good listening skills.

I unsuccessfully tried to look for it in my TAS collection, but meanwhile found a few great articles by HP on similar subjects that were really thought provocative. e.g. :

 

[Phelonious Ponk]

I can also add an interview in the 90s with the late Biil Johnson where he addressed measurements and listening carried during development of Audio Research products. He clearly sated that the classic static measurements were insufficient, and that ARC had developed some correlations between alternative methods with the help of listening. He was very specific showing that ARC was no more a one man company, but they had a good number of talented engineers, with good listening skills.

I unsuccessfully tried to look for it in my TAS collection, but meanwhile found a few great articles by HP on similar subjects that were really thought provocative. e.g. :

Thanks again, micro. I'm really curious about cause/effect here. Linkwitz builds open baffle, true bi-pole speakers. With decent dispersion (and he uses very good drivers) and very good driver control (active). These speakers have smooth response in all directions - there's your cause - and rather than dampening the room, he uses its reflective surfaces to create a very large ambient space - effect. Loudness effect boosts relatively insensitive frequencies at low volume - cause - you get the picture.

Tim

 

[RogerD]

I can also add an interview in the 90s with the late Biil Johnson where he addressed measurements and listening carried during development of Audio Research products. He clearly sated that the classic static measurements were insufficient, and that ARC had developed some correlations between alternative methods with the help of listening. He was very specific showing that ARC was no more a one man company, but they had a good number of talented engineers, with good listening skills.

I unsuccessfully tried to look for it in my TAS collection, but meanwhile found a few great articles by HP on similar subjects that were really thought provocative. e.g. :

You are not going to get where you want to go with just stereo. Even if a more linear device was put into production it would not reach the pinnacle. Vacuum tubes,transistors and FET's are all flawed. That doesn't even address the limitations of 2 speakers.

But let me make clear my system is 2 channel stereo with a psychoacoustic enhancement.