SACD vs. CD - Unfair competition?

[WmAx]

Chris,

How am I to take you seriously. You admittedly do not own DVD-A or SACD player, yet you are already dismissing the formats as unnecessary. You are trying to analyze a listening format with a bunch of technical mumbo jumbo. I am unimpressed with someone who chooses to do more talking and less listening to a format that REQUIRES listening.

As far as what you desire, I don't really care. Sorry

Technical mumbo jumbo? Do you resent controlled studies/research?

As far as 'my listening', do you think i should trust what I 'hear'? I don't. At least not the point I would try to state something as fact. Not under conditions that are not strictly controlled in order to remove psychological bias. Let's imagine I did own a SACD player. I can not compare to the RBCD layer or RBCD release, as these are very likely different masters/mixes. The only valid method would be to use a 44.1/16 A-D-A in line of the analogue SACD output and switch between the two outputs(SACD output vs. SACD output-->A-D-A output) in a carefully controlled, level matched DBT, ABX or other similar protocol and attempt to score positive signficnat statisical results. Let's assume I did score positive results...then it is still not safe to assume that the format is to blame. In this theoretical setup, I would have to analyse/measure the A-D-A system/process in order to insure that no known audible artifacts and/or distortions are being introduced to the original signal. IN addition, then the loudspeaker system or headphone would have to be analysed for these two discrete scenarios in order to see if IMD caused by non-linearity of the tranducer(s) is the cause of audibility. Not a quick task to accomplish. Besides, why should I think that I can achieve positive results where highly competant acoustics researchers have failed in a very similar subject? THis makes this particular test seemingly redundant and purposeless for me to carry out unless I suspect or identify a critical flaw in those tests which I attempt to account for in a new test.

-Chris

[Thomas_A]

My take,

the 44.1 kHz/16 bit format was tested in one of the best studios in the world (i.e. highest sound quality, Studio Blue in Stockholm) and they could not hear the difference between a high-quality analog tape and the corresponding transfer to digital. Also, down-sampling from higher sampling rates did not improve the signal audibly. So for consumers there is no need to go higher.

Thomas

[Thomas_A]

Also, a 20 kHz dithered sinewave will be perfectly reproduced by the 16/44.1 kHz standard. Increasing the sampling rate will not increase the resolution of a 20 kHz sinewave.

[Sir Terrence the Terrible]

Technical mumbo jumbo? Do you resent controlled studies/research?

As far as 'my listening', do you think i should trust what I 'hear'? I don't. At least not the point I would try to state something as fact.

Controlled studies and research have their place, and no I do not resent them. But what do people who do controlled studies have over me? They listen with their ears, and so do I. When many people LISTEN and say the same thing, then I am willing to have an open mind. Your mind is pretty closed, and I am not interested in opening it, that is up to you. I never stated anything as FACT(that's what you gathered), its is a broad based opinion. While you are quick to dimiss it, I am not. Engineers who know their stuff have as much credibility to me as a scientist does.

Not under conditions that are not strictly controlled in order to remove psychological bias. Let's imagine I did own a SACD player. I can not compare to the RBCD layer or RBCD release, as these are very likely different masters/mixes. The only valid method would be to use a 44.1/16 A-D-A in line of the analogue SACD output and switch between the two outputs(SACD output vs. SACD output-->A-D-A output) in a carefully controlled, level matched DBT, ABX or other similar protocol and attempt to score positive signficnat statisical results

A pschological bias would only exist if you were in favor of a certain format. I have no favorites and therefore no psycological bias.

I would suggest you do just what you propose instead of talking down a technology you haven't even heard. I did just what you suggested, and that is what convinced me to upgrade my processing boxes, and various equipment to handle high resolution audio. You would be surprised if you quit talking and started listening what you will learn.

. Let's assume I did score positive results...then it is still not safe to assume that the format is to blame. In this theoretical setup, I would have to analyse/measure the A-D-A system/process in order to insure that no known audible artifacts and/or distortions are being introduced to the original signal.

The already have gear to do this on the fly, so there is no need for a second process as you suggest. Much of what you mention here I would have already done in the beginning.

IN addition, then the loudspeaker system or headphone would have to be analysed for these two discrete scenarios in order to see if IMD caused by non-linearity of the tranducer(s) is the cause of audibility. Not a quick task to accomplish. Besides, why should I think that I can achieve positive results where highly competant acoustics researchers have failed in a very similar subject? THis makes this particular test seemingly redundant and purposeless for me to carry out unless I suspect or identify a critical flaw in those tests which I attempt to account for in a new test.
-Chris

When I was deciding to upgrade, I made no attempt to test so as to attain a peer review. I wasn't interested in proving, or disproving the increased bandwidth arguement. I was interested in improvements only within the audible band. My interest was to find out if it was worth the significant investment to upgrade my equipment to handle the higher resolution. After careful listening in at least 12 different studios during mixing and mastering sessions, my own listening room, several conferences and seminars, and recording sessions, I made my decision. All testing was DBT. My decision was based on what I heard, and saw on the scope, nothing more. No interest in peer review, publishing, challenging what is already known, or setting new trends, only does it improve the audio enough to warrant a upgrade.

I am not a scientist, and have no desire to do what scientist do. I do not want to publish, so I am not interested in having a protocol that passes peer scrutiny.

I have plenty of faith in my ears, I have no faith in claims made by equipment manufacturer unless my EARS can verify them. I have no biases, so my ears cannot fooled by biases. The object is to be open minded(something you have trouble doing) and if you cannot hear an improvement, then there is none to be found, test over.

[WmAx]

Engineers who know their stuff have as much credibility to me as a scientist does.

The issue of whether someone is a scientist or not is not the issue. The methodology used is the issue.

A pschological bias would only exist if you were in favor of a certain format. I have no favorites and therefore no psycological bias.

Not true. It is an error to believe that your senses can be controlled this easily.

I would suggest you do just what you propose instead of talking down a technology you haven't even heard. I did just what you suggested, and that is what convinced me to upgrade my processing boxes, and various equipment to handle high resolution audio. You would be surprised if you quit talking and started listening what you will learn.

If you have done what you seem to claim("did just what i suggested"), then publish the data including the scores, confirmed measurements of the equipment, speakers, etc.. It would be interesting -- since you would have done what acoustics researchers have not been able to do. I have no good reason to do this testing, as I specified in the last reply. I would be motivated to change this perspective if you have positive test results that stand under scrutiny.

. All testing was DBT. My decision was based on what I heard, and saw on the scope, nothing more. No interest in peer review, publishing, challenging what is already known, or setting new trends, only does it improve the audio enough to warrant a upgrade.

I do not want to publish, so I am not interested in having a protocol that passes peer scrutiny.

You are not interested in a protocol that passes peer scrutiny? But all testing was DBT, no? Double blind testing is a valid protocol. I would be very interested in the test if it was scrutinized, with no errors found.

I have no biases, so my ears cannot fooled by biases.

Not possible. Human senses are interpretted by the brain, which can and will subject your perception(s) to subconcious variables.

-Chris

[Sir Terrence the Terrible]

My take,

the 44.1 kHz/16 bit format was tested in one of the best studios in the world (i.e. highest sound quality, Studio Blue in Stockholm) and they could not hear the difference between a high-quality analog tape and the corresponding transfer to digital. Also, down-sampling from higher sampling rates did not improve the signal audibly. So for consumers there is no need to go higher.

Thomas

Thomas,
Hardly anyone uses analog tape anymore. So this is out of context with audio engineering done today. Downsampling from a higher sampling rate NEVER improves the signal, so this is a worthless statement. When I did use tape, 44.1khz NEVER sounded like my master tapes, and I think that is a pretty broad based opinion amoung most sound engineers.

[Sir Terrence the Terrible]

The issue of whether someone is a scientist or not is not the issue. The methodology used is the issue.

Sorry, but the spirit of your posts don't translate this perspective.

Not true. It is an error to believe that your senses can be controlled this easily.

It is more of an error to believe they can easily be pushed in any direction without my will.

If you have done what you seem to claim("did just what i suggested"), then publish the data including the scores, confirmed measurements of the equipment, speakers, etc.. It would be interesting -- since you would have done what acoustics researchers have not been able to do. I have no good reason to do this testing, as I specified in the last reply. I would be motivated to change this perspective if you have positive test results that stand under scrutiny.

I am not quite understanding why you do not seem to comprehend what I have written. I believe I have mentioned multiple times that I have no interest in publishing, no, I HAVE NO INTEREST IN PUBLISHING. Did you get that? Can you also get this, I HAVE NO INTEREST IN CHANGING YOUR MIND. You may think whatever you desire, it has no reflection on me, or my business.

You are not interested in a protocol that passes peer scrutiny? But all testing was DBT, no? Double blind testing is a valid protocol. I would be very interested in the test if it was scrutinized, with no errors found.

I am not interested in peer scrutiny, and DBT is what works for me when I am going to spend significant amounts of money on upgrades. That has nothing to do with my peers. What interests you, doesn't interest me obviously.

Not possible. Human senses are interpretted by the brain, which can and will subject your perception(s) to subconcious variables.

-Chris

Human senses only effected when stimulated. No stimulation, and there is nothing to be interepreted by the brain. So if I haven't heard it, then there is no stimulus, and thus no interpretation by the brain. It's just that simple, you can't be bias in a listening test if you haven't heard anything right?

I walked into this not expecting anything, not to prove anything, and not trying to disprove anything. I had just one interest, is it worth it to upgrade my equipment. If there was any bias to be found, it would have went against the results that came of my tests. I didn't really want to spend the money, so my test should have been biased against hearing any differences.

[Sir Terrence the Terrible]

Also, a 20 kHz dithered sinewave will be perfectly reproduced by the 16/44.1 kHz standard. Increasing the sampling rate will not increase the resolution of a 20 kHz sinewave.

Irrelevant, since nobody can hear that high anyway. I just used that as an example.

[E-Stat]

Also, a 20 kHz dithered sinewave will be perfectly reproduced by the 16/44.1 kHz standard. Increasing the sampling rate will not increase the resolution of a 20 kHz sinewave.

Great news for everyone who listens to sine waves.

rw

[mtrycraft]

Great news for everyone who listens to sine waves.

rw

Ah, the straw man argument, unsupported by facts. What else is new?

[mtrycraft]

Irrelevant, since nobody can hear that high anyway. I just used that as an example.

Then what's the beef?

[WmAx]

Human senses only effected when stimulated. No stimulation, and there is nothing to be interepreted by the brain. So if I haven't heard it, then there is no stimulus, and thus no interpretation by the brain. It's just that simple, you can't be bias in a listening test if you haven't heard anything right?

With NO other variables this is true, and why DBT and ABX testing is extremely important in testing. However, in lack of protocols such as these, variables such as look, name, color, sound of the name, etc., etc. can effect your perception of what you *think that you may or may not hear. These work on a subconscious level, are subject to great variability and can not be over-ridden. DBT and ABX protocols prevent one from knowing exactly what they are listening to at a specific point in time so that potentially only the actual audible properties are present in the test -- not the other factors.

Since you have made it clear in a recent reply that is only your opinion(and that you are not asserting as fact) that a braoder bandwidth then RBCD provides is audible --- I don't understand what you are arguing in that regard or why you persist in that issue since I have constantly made a point that I am only interested in scientifically valid research with this subject - not speculation(s). If your supposed point is that most recording engineers 'believe' a higher bandwidth is audible for playback purposes - then I acknowledge that you made this point and I acknowledge that I read what you stated.

If you choose to once again argue this point based solely on popular opinion without the support of valid research/testing to validate this assertion, I will not reply to you again in this thread concernig this subject.

If you have something new or different to discuss, I'll be glad to reply.

-Chris

[Thomas_A]

Thomas,
Hardly anyone uses analog tape anymore. So this is out of context with audio engineering done today. Downsampling from a higher sampling rate NEVER improves the signal, so this is a worthless statement. When I did use tape, 44.1khz NEVER sounded like my master tapes, and I think that is a pretty broad based opinion amoung most sound engineers.

That's entitled to you opinion. Studio Blue in Stockholm uses the best equipment there is, and also, a place where scientific tests (i.e. blind tests) are performed. They were not able to distinguish the original master from the 16/44.1 kHz digitial copy when done under blind conditions.

T

[Thomas_A]

Irrelevant, since nobody can hear that high anyway. I just used that as an example.

Me too, I just used it as an example. The resolution of the 20 kHz sine wave will be no better at 192 kHz sampling rate. A 10 kHz square wave will look better, but since few can hear above about 18 kHz, it is as you say, irrelevant.

T

[Sir Terrence the Terrible]

With NO other variables this is true, and why DBT and ABX testing is extremely important in testing. However, in lack of protocols such as these, variables such as look, name, color, sound of the name, etc., etc. can effect your perception of what you *think that you may or may not hear. These work on a subconscious level, are subject to great variability and can not be over-ridden.

If you don't care about the look, name, color, sound of the name or any variable you present, then you arguement is moot. Don't you have control over your own brain? Can't you discipline your own mind? I came to listen, not look. A black box with the name Lexicon tells me nothing about how that product sounds. Once again I say to you, something has to be written to be over-written. The only thing written in my mind when I approach this is prove to me that your sound is worth the money. With that kind of attitude it is very difficult to be biased in favor of the product.

DBT and ABX protocols prevent one from knowing exactly what they are listening to at a specific point in time so that potentially only the actual audible properties are present in the test -- not the other factors.

You are preaching to the choir here.

Since you have made it clear in a recent reply that is only your opinion(and that you are not asserting as fact) that a braoder bandwidth then RBCD provides is audible --- I don't understand what you are arguing in that regard or why you persist in that issue since I have constantly made a point that I am only interested in scientifically valid research with this subject - not speculation(s).

It is apparent to me your mind is not keeping up with the thread. I took bandwidth off the table several responses ago. That was NEVER my arguement, its only what you choose to latch onto. My arguement is simple, 16/44.1khz is not good enough and it never was. That has been a complaint loooooong echo'd by audio engineers. It sounds digital, and nothing like the analog component it was sampled from. That is my arguement. Now I hope you get it this time so it doesn't have to be mentioned in every thread.

If your supposed point is that most recording engineers 'believe' a higher bandwidth is audible for playback purposes - then I acknowledge that you made this point and I acknowledge that I read what you stated.

No Chris, this was not my point at all, what have you been reading these last several posts? Recording engineers believe that imaging, clarity, and tonality are improved by a higher sampling rate, not bandwidth. Bandwidth cannot be quickly dismissed, as the most recent testing at AES proved inconclusive. Unless something can be ruled completely out, then you cannot remove it's possibility

If you choose to once again argue this point based solely on popular opinion without the support of valid research/testing to validate this assertion, I will not reply to you again in this thread concernig this subject.

If you have something new or different to discuss, I'll be glad to reply.

-Chris

Chris, you don't have to reply, and I hope you don't. You haven't one clue about the contents of this discussion based on what you wrote here. I feel like I have been talking to a wall that talks, but cannot read. You have argued one point, and stuck with that point even though it hasn't been apart of this discussion for days. So please, take you ball and jacks and go home!

[Sir Terrence the Terrible]

That's entitled to you opinion. Studio Blue in Stockholm uses the best equipment there is, and also, a place where scientific tests (i.e. blind tests) are performed. They were not able to distinguish the original master from the 16/44.1 kHz digitial copy when done under blind conditions.
T

Thomas, that is not the only studio in the world that testing has been conducted. And what constitutes the BEST of anything is in the eye(or ear) of the beholder. Blind testing has been done in studio's all over the world, so there is nothing special or unique about studio blue. Gateaway Studio's in Los Angeles has been called the best mastering studio in the world, does that make it any better than Studio Blue?

If what you state is true concerning 16/44.1khz, then why do audio engineers have to tweak it some much to make it sound like the master tape? Why do I hear over and over at AES that 16/44.khz was never transparent when compared to the master tapes? I heard this myself at AES this year when they compared a master tape to red book CD 16/44.1khz, 16/48khz, 16/96khz, 24/44.1khz, 24/48khz and 24/96khz. 16/44.1khz and 24/44.1khz sounded subtlely(and sometimes not so subtle)different from the master depending on the genre of music that was played. I heard this with my own ears, instead of repeating what I read somewhere.

[Thomas_A]

Thomas, that is not the only studio in the world that testing has been conducted. And what constitutes the BEST of anything is in the eye(or ear) of the beholder. Blind testing has been done in studio's all over the world, so there is nothing special or unique about studio blue. Gateaway Studio's in Los Angeles has been called the best mastering studio in the world, does that make it any better than Studio Blue?

If what you state is true concerning 16/44.1khz, then why do audio engineers have to tweak it some much to make it sound like the master tape? Why do I hear over and over at AES that 16/44.khz was never transparent when compared to the master tapes? I heard this myself at AES this year when they compared a master tape to red book CD 16/44.1khz, 16/48khz, 16/96khz, 24/44.1khz, 24/48khz and 24/96khz. 16/44.1khz and 24/44.1khz sounded subtlely(and sometimes not so subtle)different from the master depending on the genre of music that was played. I heard this with my own ears, instead of repeating what I read somewhere.

All equipment in Studio Blue has been tested for transparency using before/after tests or bypass/wire tests. The speaker system are capable of producing sound at realistic levels with very low distortion, e.g. reproducing a drum set at played at maximal possible level. The maximal level is 139 dB @ 20 Hz in-room response, before distorsion starts rise rapidly. Also, the speakers are recreating the original waveform, i.e. squarewaves and impulse responses. Those who have worked there praise it to be world-leading, e.g.

Cited and translated to english:
Roger Hinchliffe
american artist
"Studio Blue is the best Studio that I have worked in. Even studios in USA have a long way to go to match the sound quality in Studio Blue"

The link is in Swedish though and the studio is first of all a place for education of recording engineers.

http://www.studioblue.se/

I don't say that there are many other good studios, but can you really be sure that previous tests have included a careful selection method for the best and transparent equipment for a digital transfer? Can you be sure that there has been non-biased testing procedures?

T

[Sir Terrence the Terrible]

All equipment in Studio Blue has been tested for transparency using before/after tests or bypass/wire tests. The speaker system are capable of producing sound at realistic levels with very low distortion, e.g. reproducing a drum set at played at maximal possible level. The maximal level is 139 dB @ 20 Hz in-room response, before distorsion starts rise rapidly. Also, the speakers are recreating the original waveform, i.e. squarewaves and impulse responses. Those who have worked there praise it to be world-leading, e.g.

Alot of very good studios do the very same thing as this studio. Nothing noteworthy here.

Cited and translated to english:
Roger Hinchliffe
american artist
"Studio Blue is the best Studio that I have worked in. Even studios in USA have a long way to go to match the sound quality in Studio Blue"

The link is in Swedish though and the studio is first of all a place for education of recording engineers.

http://www.studioblue.se/

I have never heard of the artist you have mentioned, but I have heard simular comments made about Gateaway studio's, Chuck Ainley studio's in Memphis, Elliot Schieners studio, Mi Casa in Los Angeles, Capitol Studio's in Hollywood, The Sound Plant here in San Francisco, Fantasy Studio's in Berkeley Cal. and the list goes on.

The stat's you mention for this studio are not above any high end studio in America.

I don't say that there are many other good studios, but can you really be sure that previous tests have included a careful selection method for the best and transparent equipment for a digital transfer? Can you be sure that there has been non-biased testing procedures?

Are you insinuating that this place is the only proper place in the world were PROPER DBT test can be conducted? That's absurd! Surely you can see the foolishness of your own statement. AES does credible DBT at studio's all over the world. This studio you mention is not special in any way from other very good high end recording studio

[Thomas_A]

Alot of very good studios do the very same thing as this studio. Nothing noteworthy here.



I have never heard of the artist you have mentioned, but I have heard simular comments made about Gateaway studio's, Chuck Ainley studio's in Memphis, Elliot Schieners studio, Mi Casa in Los Angeles, Capitol Studio's in Hollywood, The Sound Plant here in San Francisco, Fantasy Studio's in Berkeley Cal. and the list goes on.

The stat's you mention for this studio are not above any high end studio in America.



Are you insinuating that this place is the only proper place in the world were PROPER DBT test can be conducted? That's absurd! Surely you can see the foolishness of your own statement. AES does credible DBT at studio's all over the world. This studio you mention is not special in any way from other very good high end recording studio

First, I am not insuinuating anything, but you have not provided anything that can be discussed so far.

Secondly, what studio use speakers that recreate the original waveform through the monitor speakers with ±1 dB 20 Hz to 20 khz at listening position (extending up to 40 kHz ± 3 dB), up to 139 dB SPL @ 20 Hz? Name 10 studios in the world that can do that.

Third, are you "insinuating" that digital transfers 16/44.1 khz when made with the highest possible standard is audibly different from the original? Or can you point out a series of peer reviewed articles that independently and consistently can distinguish the digital copy from the master?

[DMK]

Cited and translated to english:
Roger Hinchliffe
american artist
"Studio Blue is the best Studio that I have worked in. Even studios in USA have a long way to go to match the sound quality in Studio Blue
T

That sounds amazingly like a testimonial! Where are Mr Hinchliffe's citations and peer reviewed papers?

Sorry... YOU left the opening!

[mtrycraft]

Human senses only effected when stimulated. No stimulation, and there is nothing to be interepreted by the brain.


Are you so sure about this?

Have you never responded just to be told they didn't ask a question or say anything to be responded to? Oh, please. The brain make up things all the time. Why do you think you use DBT then?

So if I haven't heard it, then there is no stimulus, and thus no interpretation by the brain. It's just that simple, you can't be bias in a listening test if you haven't heard anything right?

That is too funny to respond to, from a professional. Or, is that rhetorical?

[Sir Terrence the Terrible]

First, I am not insuinuating anything, but you have not provided anything that can be discussed so far.

I believe it was you who chimed in rather late in this discussion. What needed to be said, already has.

Secondly, what studio use speakers that recreate the original waveform through the monitor speakers with ±1 dB 20 Hz to 20 khz at listening position (extending up to 40 kHz ± 3 dB), up to 139 dB SPL @ 20 Hz? Name 10 studios in the world that can do that.

Irrelevant to the topic at hand, please stay on the topic being discussed, you are hijacking this thread.

Third, are you "insinuating" that digital transfers 16/44.1 khz when made with the highest possible standard is audibly different from the original? Or can you point out a series of peer reviewed articles that independently and consistently can distinguish the digital copy from the master?[/QUOTE]

Not many recording are made to the highest of standards. Economics prevent this from happening. So this is out of line with reality, and does not represent everyday events from which I am coming from. VERY few audio engineers publish, but they do hold listening seminars. The one comment you hear over and over amoung those in my industry is that 16/44.1khz blunts transients, cannot reproduce muted trumpets, cymbals, or any other instruments with high frequency harmonics. this is almost universally heard in every seminar I have attended in the last couple of years. Where there is smoke, there is fire, and when so many people say the same thing, my ears perk up. When this information is delivered via some of the best audio engineers in the world, I am definately going to pay some attention. When I experience it myself, then it really drives the point home.

Since I have nothing to prove to you(or anyone else for that matter) I see no need in providing anyone with peer reviewed papers or articles.



As far as I am concerned, this thread is dead. It's just going around, and around in circles.

[Sir Terrence the Terrible]

Human senses only effected when stimulated. No stimulation, and there is nothing to be interepreted by the brain.


Are you so sure about this?

Have you never responded just to be told they didn't ask a question or say anything to be responded to? Oh, please. The brain make up things all the time. Why do you think you use DBT then?

So if I haven't heard it, then there is no stimulus, and thus no interpretation by the brain. It's just that simple, you can't be bias in a listening test if you haven't heard anything right?

That is too funny to respond to, from a professional. Or, is that rhetorical?

Mtry, just because you are a weak minded fool doesn't mean everyone is

[E-Stat]

Ah, the straw man argument, unsupported by facts. What else is new?

I forget that in your non-experience world there is no music. My apologies. Enjoy your test tones.

rw

[Thomas_A]

That sounds amazingly like a testimonial! Where are Mr Hinchliffe's citations and peer reviewed papers?

Sorry... YOU left the opening!

Well,

the issue in this thread is whether 16/44.1 is transparent or not. I have provided some data of the studio where the 16/44.1 tests were made. Besides, how do you test a studio in a peer reviewed report? One can start with the weakest point, the speakers, for which I already have mentioned some spec. I also mentioned the procedure for testing the equipment, with before/after test. If you don't know the method, see:

http://www.sonicdesign.se/amptest.htm

So, again, what studio has the spec I mentioned?

And if the digital transfer has been made with the highest quality standard and listened to with carefully selected equipment with no audible loss under blind conditions, what are the conditions where the 16/44.1 khz standard has been detected to be audibly different? Have there been controlled listening tests with removal of bias? Apparently, it is not known, as I understand it from this thread. It is only "generelly agreed" among studio people, that the 16/44.1 is not good enough. Since studio people I know has another opinion based on controlled listening tests with some of the best equpiments that can be bought for money and there apparently appear to be no peer reviewed report of audible difference, why should anyone believe the "general opinion"?

T