My Lying Ears

That's actually not correct.

 

A/B/X is not the only way to do double-blinded tests, and it may be far from the best way, depending on what you are testing for.

Thanks for pointing that out. There are many ways to perform blinded testing. IMO SBT styled testing is very doable for audio.

Sure. On the flip side, anything that would make the mic less effective would be a concern, and similarly for anything that would affect the ability of the human listener to discriminate.

I hope you aren't championing the position that any form of discriminate testing would fall into scope of "affect the ability of the human listener to discriminate".

I hope you aren't championing the position that any form of discriminate testing would fall into scope of "affect the ability of the human listener to discriminate".

Nope. I'm thinking you're probably familiar enough with my posts by now that you know I don't like sweeping generalizations like that.

As one example of something I'd trust people to discriminate, I think people are great at discriminating volume, to the point that people will prefer a sample so slightly louder they don't even consciously realize it. Conversely, for the same reason, I would not trust people to discriminate between two samples unless they were *very* closely volume matched.

Lots of references here: The Well-Tempered Computer

Hadn't looked at the welltemperedcomputer link in a while, thanks - there's lots of good info there

I followed the link to Nwavguy blog & one thing occurs to me - he shows a number of jitter measurements for different devices & I can't see much distortion above -100dB (except for some low frequency jitter).

The thing is - what is the "accepted" audibility threshold for small distortions?

This thread on Head-fi is a good read when Ultmusicsnob starts to post & actually do some Foobar ABX tests on different music files that have various amounts of correlated & uncorrelated jitter added

Through the thread he does ABX tests on files which have less & less jitter. Here's one of his later ABX tests Jitter Correlation to Audibility - Page 13

And there are a number of interesting aspects to this:

- the guy is very unique in his ability to isolated & be able to focus on the differences during an ABX test

- the files have been analysed & any distortions are down below -90dB

- he has an amazing ability to switch his listening from one difference aspect in the sound to another

I'm not sure what all this says about our "lying ears" Some things I take away:

- I intend to download these files if they are still available but I doubt I will be able to tell a difference in an A/B

- it would be interesting to see if a difference would be noticeable in long term listening (but not necessarily the ability to explicitly identify the difference

- Doing a successful AB test is very difficult

Conversely, for the same reason, I would not trust people to discriminate between two samples unless they were *very* closely volume matched.

Sorry if that was confusing, I meant if the test was for ability to discriminate for a factor other than loudness or loudness-based preference.

I'm not pushing any agenda or endorsing a point of view by publishing this article. I simply think a worthwhile read for all who enjoy this hobby as much as I do.

While you’re not endorsing a point, the author was doing so. After a most circuitous path, which most perceptive, thoughtful, and introspective audiophiles have experienced, his conclusion is: that only when differences are measurable, should a "proper" listening test be conducted.

Wow, what a statement? What does measurable mean? What equipment is used to conduct those measurements? Who is doing the measuring? What parameters are being measured? If there are no measurable differences using whatever techniques and equipment, then a listening test isn't warranted? In support of JRiver, could this be more of the musings of the Consigliere of audio measurements: Archimago? Are we with certitude, to believe that aural differences can always be measured by Archimago, or for that matter anyone else?

Via a well written, cogent description of what many of us have indeed experienced, this poster on JRiver’s forum appears to be providing a backhanded way for JRiver to nullify the cited listening test’s findings (only “4 out of 38” votes for JRMC) and continue the bits-is-bits; they therefore must ALL sound the same, argument. That is, unless differences between bit perfect players can be measured, the players all have the same outcome -- i.e. there is no need to conduct a listening test, "proper" or otherwise! Really, is that the "non-agenda" driven, "worthwhile" conclusion that motivated this submittal?

As a user of JRMC from 16 to now, 21, I’m neither in favor of it sounding the same as other players, nor against that conclusion. My mind is open on the subject. There are just too many variables for me to reach a 100% conclusion. Thus, I believe that there is room for measurements and listening tests and unlike the original JRiver poster; I don’t believe one precludes the other! I frequent forums such as this for healthy, mainly subjective debate. As such, I find dogma unacceptable; especially about such a subjective subject as audio reproduction.

I do however, believe that JRMC has backed themselves in a corner and will never come out, no matter how many listening tests or measurements suggest otherwise. The boxing ring corners have been established and they will never change! As a paying and satisfied customer of JRMC, I find this to be an unfortunate disservice to themselves and to audiophiles in general.

As have many have done when seeking scientific certitude, perhaps when that goal is unattainable, tests have been designed to prove what the tester or funder preferred to prove and/or otherwise. Sometimes we will know that is the case, other times not so much. And so it goes…..

The thing is - what is the "accepted" audibility threshold for small distortions?

The page I linked references some studies on that subject, e.g. by the BBC.

The page I linked references some studies on that subject, e.g. by the BBC.

Thanks but random jitter is not of that much interest as it is just translates into a fixed level of gaussian noise - data-correlated jitter is of much more interest as it translates into the spikes you see on jitter graphs

I don't know if there a study that shows the audibility level of this form of jitter?

Furthermore, I'm of the opinion that it's mistaken & simplistic to dismiss close-in jitter on the basis that it is close to & therefore will be masked by the main frequency tone. This means that low frequency jitter would be much more important than is thought

Thanks but random jitter is not of that much interest as it is just translates into a fixed level of gaussian noise - data-correlated jitter is of much more interest as it translates into the spikes you see on jitter graphs

 

I don't know if there a study that shows the audibility level of this form of jitter?

If it's of any help, jitter is equivalent to frequency modulation.

If it's of any help, jitter is equivalent to frequency modulation.

That's why it's measured as "phase noise."

(I'm not disagreeing with you, I don't have the technical background. Just thought the frequency/phase dichotomy was funny/interesting.)

That's actually not correct.

 

 

 

A/B/X is not the only way to do double-blinded tests, and it may be far from the best way, depending on what you are testing for.

Your entitled to your opinion, you just happen to be wrong.

Wow, what a statement? What does measurable mean? What equipment is used to conduct those measurements? Who is doing the measuring? What parameters are being measured? If there are no measurable differences using whatever techniques and equipment, then a listening test isn't warranted? In support of JRiver, could this be more of the musings of the Consigliere of audio measurements: Archimago? Are we with certitude, to believe that aural differences can always be measured by Archimago, or for that matter anyone else?

Such a grea point, and one that I have been trying to make for a long time. All these people who are so in denial of advances in certain areas just because they can't yet measure them. Yet they have it so backwards. When literally thousands of people around the world report hearing something, why does that not count as a valid data to inspire them to investigate and figure out why and where their measurement techniques fall short?

The fact is, the engineers designing products have always used a combination of measurement and listening, and those that do end up with the most compelling and successful components. Believe me, it is not an accident.

Your entitled to your opinion, you just happen to be wrong.

Another pseudo scientist who spouts "objectivity and measurements" - but doesn't actually understand testing.

Actual scientists will agree with Jud. Do a little research yourself and you will find it to be true.

That's why it's measured as "phase noise."

 

(I'm not disagreeing with you, I don't have the technical background. Just thought the frequency/phase dichotomy was funny/interesting.)

Now that I think about it again, phase modulation would be a more accurate description. That said, frequency and phase modulation are rather similar when the modulating signal is more or less periodic. Shifting the phase of the base signal is the same thing as briefly raising or lowering its frequency.

Such a grea point, and one that I have been trying to make for a long time. All these people who are so in denial of advances in certain areas just because they can't yet measure them. Yet they have it so backwards. When literally thousands of people around the world report hearing something, why does that not count as a valid data to inspire them to investigate and figure out why and where their measurement techniques fall short?

If a lot of people report hearing something, that's certainly cause for an investigation. Now if a multitude of highly accurate measurements fail to turn up any explanation, the logical conclusion at some point must be that the subjective experience is caused by something else.

It is often pointed out that the exact workings of the ear and the auditory processing in the brain are not well understood, and this is true. However, the science behind DACs and amps is very well established. It is extremely unlikely that there are processes going on within these devices of which we are unaware.

I'm hearing something because someone else said they heard something !

If a lot of people report hearing something, that's certainly cause for an investigation. Now if a multitude of highly accurate measurements fail to turn up any explanation, the logical conclusion at some point must be that the subjective experience is caused by something else.

 

It is often pointed out that the exact workings of the ear and the auditory processing in the brain are not well understood, and this is true. However, the science behind DACs and amps is very well established. It is extremely unlikely that there are processes going on within these devices of which we are unaware.

You nearly got there but you fell at the last hurdle.

It's at the interface of what these devices output & auditory perception - that's where it's not well established.

The illusion that's created is not well understood.

Are you saying that the device is completely & fully characterised by that a multitude of highly accurate measurements?

If you are can you give the list of measurements needed to fully characterise:

- an amplifier

- a DAC

- a speaker

- the interfaces between each of these devices

- a full audio system end to end

Because this would put the issue to bed

....can you give the list of measurements needed to fully characterise:

- an amplifier

- a DAC

- a speaker

- the interfaces between each of these devices

- a full audio system end to end

And after doing this characterization, please advise which components in these categories will produce the best recreation of a recorded performance in our homes/listening rooms. If you can do this with an accurate level of confidence amongst the purchasers of such equipment, it would be a godsend; a reason for most equipment manufacturers, forums, and periodicals to go belly up.

In fact, a product could be designed to comply with the science behind your findings and only one product/manufacturer in each category would be needed to satisfy our desire to recreate the best possible reproduction - done, end of story! We can all put this and most every other audio forum to bed. Other than music, what would we have to discuss? Or more importantly, if it wasn’t for our personal, not measurement findings, what would we have to post about? I say “not measurement findings”, because I really don’t frequent this or any other forum for scientific or measurement data. I visit such sites to have a clue about what is piquing everyone’s audio fancy from their listening and use perspective. If there is no scientific or measurable data to defend it and I buy it, the onus is on me, not on someone trying to save me from me!

There will never be an agreement amongst us audiophiles based on measurements, listening or otherwise, that will provide a best to worst list of equipment in each of the available categories. That has been done, is being done and I pay little, to zero attention to same!

Discussing what measurement or listening technique is the de facto standard is a waste of time. Measurements have their place as does listening. One is neither mutually exclusive, nor for me, better than the other.

We're dealing with a hobby that is an emotionally driven one; which, by definition, is a subjective one. Can engineering, science and listening help design great equipment, or answer some of our questions, and resolve some of our issues? Sure, but not all! Perhaps an EKG needs to be put in the measurement mix. Who knows what else?

However, my ears are presently the final arbiter of product purchases, not measurements. In fact, measurements, scientific and engineering information rarely rate in any of my buying decisions. On the other hand, my feelings about what I’m hearing are always at the top of my priority list. And while I was trained in the scientific method and utilized it, and more than fully appreciate it, when it comes to my audio room, or the concert hall, let the scientific method be damned. My main objective is to be whisked into the midst of a performance as fully and emotionally as I can be! If that happens, I really don't care about the science behind it! So to get back to the post that Chris referenced, and the poster’s conclusion amidst all the self-consternation: we must have measurable differences between components, music players etc., before conducting listening tests? No, a thousand times NO!

However, the science behind DACs and amps is very well established. It is extremely unlikely that there are processes going on within these devices of which we are unaware.

Except that there ARE many processes going on that are neither well understood nor focused on. Three examples:

1) Bruno Putzeys' articles and work with high amounts of negative feedback over a very wide bandwidth;

2) John Swenson's measurements of ground-plane and packet-data noise from USB PHY/MAC circuits making it all the way through to the master clock input of DAC chips regardless of buffers, isolators, and reclocking;

3) Mike Moffat (and his academia team) upending conventional Parks-McClellan digital filter optimization to put forth a fresh method of upsampling that preserves all original samples.

Each of the above examples were development processes that used a combination of measurement and listening to verify the efficacy of the original hypothesis.

and after doing this characterization, please advise which components in these categories will produce the best recreation of a recorded performance in our homes/listening rooms. If you can do this with an accurate level of confidence amongst the purchasers of such equipment, it would be a godsend; a reason for most equipment manufacturers, forums, and periodicals to go belly up.

 

In fact, a product could be designed to comply with the science behind your findings and only one product/manufacturer in each category would be needed to satisfy our desire to recreate the best possible reproduction - done, end of story! We can all put this and most every other audio forum to bed. Other than music, what would we have to discuss? Or more importantly, if it wasn’t for our personal, not measurement findings, what would we have to post about? I say “not measurement findings”, because i really don’t frequent this or any other forum for scientific or measurement data. I visit such sites to have a clue about what is piquing everyone’s audio fancy from their listening and use perspective. If there is no scientific or measurable data to defend it and i buy it, the onus is on me, not on someone trying to save me from me!

 

There will never be an agreement amongst us audiophiles based on measurements, listening or otherwise, that will provide a best to worst list of equipment in each of the available categories. That has been done, is being done and i pay little, to zero attention to same!

 

Discussing what measurement or listening technique is the de facto standard is a waste of time. Measurements have their place as does listening. One is neither mutually exclusive, nor for me, better than the other.

 

We're dealing with a hobby that is an emotionally driven one; which, by definition, is a subjective one. Can engineering, science and listening help design great equipment, or answer some of our questions, and resolve some of our issues? Sure, but not all! Perhaps an ekg needs to be put in the measurement mix. Who knows what else?

 

However, my ears are presently the final arbiter of product purchases, not measurements. In fact, measurements, scientific and engineering information rarely rate in any of my buying decisions. On the other hand, my feelings about what i’m hearing are always at the top of my priority list. And while i was trained in the scientific method and utilized it, and more than fully appreciate it, when it comes to my audio room, or the concert hall, let the scientific method be damned. My main objective is to be whisked into the midst of a performance as fully and emotionally as i can be! If that happens, i really don't care about the science behind it! So to get back to the post that chris referenced, and the poster’s conclusion amidst all the self-consternation: We must have measurable differences between components, music players etc., before conducting listening tests? No, a thousand times no!

Great post Mike!!

3) Mike Moffat (and his academia team) upending conventional Parks-McClellan digital filter optimization to put forth a fresh method of upsampling that preserves all original samples.

 

Each of the above examples were development processes that used a combination of measurement and listening to verify the efficacy of the original hypothesis.

While I agree with your general line of thought, Mike Moffat implemented that filtering decades ago in the Theta products. Silicon available these days (and perhaps design tools as well?) no doubt allows for better realization than was possible then. For example, I'm reasonably sure the old Theta DACs didn't have 15,000 taps.

I also think there are at least a couple of other folks with ideas along generally similar lines.

The foregoing may sound as if I feel Mike Moffat's work is less special than I actually do. I'm very excited to hear an Yggdrasil.

I'm very excited to hear an Yggdrasil.

Yes, me too. I may have to buy one to hear it.

Thanks for posting this. Being new to the "audiophile" world, I was perplexed by this article when I read it last night:

 

 

Two USB Cables | The Absolute Sound

 

 

Specificaly, how can the physical properties/quality of a usb cable specifically target "the middle range of the musical spectrum" of a digital signal? How can the "analog" electrical pulse that travels down a USB cable be effected in such a way (and it is of course influenced by its physical environment as all physical/"analog" signals are) that specifically targets digital information only in "the middle range of the musical spectrum", and in such a way that the buffer/DAC is "influenced" by said information change and passes it on down the chain? It defies any explanation that I am aware of - and I suspect it is all in the reviewers head.

 

 

Again, thanks for the perspective this essay provides...

Ringing and eddy currents cause electrical distortions that affect the amplifier that can heard if you are listening on good equipment. much has been learned about electrical distortion and its effects. Poor quality cable, crappy solder and poorly soldered joints, oxide buildup on connectors cause measure able ringing and electrical noise.

Of course much of what read in this thread seems pretty self congratulatory on how you guys can't hear anything. So yea, waste of typing here, I know.

Just do this, listen to your favorite music for a while. Then disconnect and reconnect every cable on your system and then listen again. Respond back on whether it sounds different or not.

Ringing and eddy currents cause electrical distortions that affect the amplifier that can heard if you are listening on good equipment. much has been learned about electrical distortion and its effects. Poor quality cable, crappy solder and poorly soldered joints, oxide buildup on connectors cause measure able ringing and electrical noise.

 

 

Of course much of what read in this thread seems pretty self congratulatory on how you guys can't hear anything. So yea, waste of typing here, I know.

 

Just do this, listen to your favorite music for a while. Then disconnect and reconnect every cable on your system and then listen again. Respond back on whether it sounds different or not.

If the cables have been plugged in a while, of course it will sound different. The contacts corrode slightly over time, and reseating them produces a better contact. There is nothing controversial about that. Now, Quantum Tunneling cables, those are much more debatable.

If the cables have been plugged in a while, of course it will sound different. The contacts corrode slightly over time, and reseating them produces a better contact. There is nothing controversial about that.

This is true for analogue cables, or at least it can be if corrosion is bad enough (gold-plated contacts in a typical home environment don't corrode much). For digital cables, if the bits get through unmolested, they sound the same even if the contacts are not perfect. There is nothing controversial about that.