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Topic: AES 2009 Audio Myths Workshop (Read 166748 times) previous topic - next topic
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AES 2009 Audio Myths Workshop

I saw this video linked in the FL Studio forum.  I say this should be a mandatory watching for anyone frequenting audio / video forums.  I learned more in an hour from these this video than from five years reading audiophile forum arguments.

Audio Myths Workshop ~ 60 minutes
At the beginning of the video, JJ talks a little about human hearing, and Poppy gives a very humorous demonstration on the power of suggestion.  The remainder of the video is Ethan Winer giving demonstrations of what can actually be heard with respect to things like dither, eq, resampling, consumer vs prosumer sound cards, microphones, amplifiers, etc.

There is also an excerpt about dither ~ 3 minutes, but I'm apparently not understanding what JJ is saying about why we should dither.

AES 2009 Audio Myths Workshop

Reply #2 –
thanks for this

AES 2009 Audio Myths Workshop

Reply #3 –
Cool, thanks for this stuff! Unfortunately, I couldn't join the last AES.

Quote from: hellokeith on
..., but I'm apparently not understanding what JJ is saying about why we should dither.

Does he even say why in these 3 minutes? I just hear him say "You really should always dither. Probably just TPD." I'm partially with JJ. If your recording already contains enough self-noise (from microphones, A/D conversion, or tape hiss), you effectively already have dither. If it doesn't, then yes, you should, because it greatly reduces possible harmonic distortion. See the figures in this article.

Chris
If I don't reply to your reply, it means I agree with you.

AES 2009 Audio Myths Workshop

Reply #4 –
thanks for the link. i'll watch it when i have some time.

AES 2009 Audio Myths Workshop

Reply #5 –
It's neat putting voices and faces to some of the names I've seen around here. Wonderful presentation!

AES 2009 Audio Myths Workshop

Reply #6 –
The Zeppelin presentation is great, even my non-geek friends got a kick out of it.

AES 2009 Audio Myths Workshop

Reply #7 –
Quote from: Canar on
It's neat putting voices and faces to some of the names I've seen around here. Wonderful presentation!


Yes, I share both experience and verdict. When talking about faces don't forget heads. JJ's looks enormous, almost twice the volume of Poppy's it seems. But when you look at his vita, he surely knew to capitalize on that... 

While the presentation was very insightful, (at least for the studio) I don't share the blunt rejection of euphonically distorting gear, just because anything can be simulated once understood. It can, no question, but it requires completely different workflows. The purpose euphonically distorting gear can serve is what could be called 'reified complexity reduction'.

There are creative types who produce fabulous sound through other means than complete rational and reflective penetration of all theoretical concepts involved in their work. You put them in front of Izotope Ozone's EQ alone, with its 9,578097130411812e+52 possible configurations, and it will make them sweat. Give them a couple of boxes they are familiar with, with knobs they can touch, and they will produce wonderful stuff instead.

I don't know, the latter might be a moribund species. But I have younger friends studying electronic composition and production, who sometimes tell me that they can do so much nowadays, that they don't even know what to do anymore. Let alone were to start.

AES 2009 Audio Myths Workshop

Reply #8 –
Quote from: rpp3po on
While the presentation was very insightful, (at least for the studio) I don't share the blunt rejection of euphonically distorting gear, just because anything can be simulated once understood. It can, no question, but it requires completely different workflows. The purpose euphonically distorting gear can serve is what could be called 'reified complexity reduction'.


The panel was (and is) not unanamous on the idea of rejecting euphony.  Especially at the source end, my position (which was said somewhere) is that you use what you want to get the sound you want. To the extent euphony is part of the desired target, it's simply part of the art, and arguing with personal taste is pointless.

At the playback end, various people (Ethan, Floyd Toole in a different way) argue for accuracy, Floyd with rather more sophisticated criteria, arguing the point that we ought to hear what the content provider intended.

I think we ought to be able to do that, but arguing with the listener's preference seems, well, odd.  Provide them with what you want, and if they choose rationally to add some kind of shaping or distortion for their own listening, that's all there is to it.  My problem with this kind of enthusiast behavior is when a distortion, shaping, or other modification is added and then the difference is claimed to be "more accurate" or "containing more information", or any kind of claim of superiority that goes beyond the individual.

And, one of my points was that SNR itself is not sufficient to know if something is going to have a distorted sound.  Short-term spectrum, at least, is required.
-----
J. D. (jj) Johnston

AES 2009 Audio Myths Workshop

Reply #9 –
You guys should publish a premium audio magazine! High quality journalism, printed on fine paper, and sold at premium prices (up to $50 per issue) is selling fantastically nowadays. People seem to be willing to pay for quality again, despite (or because of) the decline of the mass publishing industry. Sophisticated reviews, DIY speaker and room correction projects, measurement tutorials - 100% focus onto the true weak links. I think you would find your audience. Of course, an impediment could be that you may have better things to do.

AES 2009 Audio Myths Workshop

Reply #10 –
Quote from: Woodinville on
Especially at the source end, my position (which was said somewhere) is that you use what you want to get the sound you want. To the extent euphony is part of the desired target, it's simply part of the art, and arguing with personal taste is pointless.

That's my position too. My point with "high fidelity" from a recording perspective is you do whatever is needed to get the sound you want. Maybe you'll stick a microphone under the radiator, or run a singer's voice through an old tube guitar amp. Doesn't matter. But once you have the sound you want, then accuracy is what matters most, to preserve that sound intact. I make this point all the time in audio forums. I'll be talking about fidelity only, and some clown will say he likes the distorted sound he gets from pushing his preamp. Fine, but that's not what I was talking about!

--Ethan
I believe in Truth, Justice, and the Scientific Method

AES 2009 Audio Myths Workshop

Reply #11 –
I took a look around at the discussions of this video on some other web forums. Then I came back here and took a look at this thread. Not only was it so non-controversial that it wasn't mentioned for weeks, but there's no rabid "debate" about the content therein. Just lovely.

AES 2009 Audio Myths Workshop

Reply #12 –
Quote from: Canar on
I took a look around at the discussions of this video on some other web forums. Then I came back here and took a look at this thread. Not only was it so non-controversial that it wasn't mentioned for weeks, but there's no rabid "debate" about the content therein. Just lovely.


Well, not being welcome at "the asylum" any more, I have no idea what kind of cockamamie codswallop they conjured to commit complete chaos, but I'm not surprised here, it's kinda "preaching to the seminary" except for the lack of the belief requirement...
-----
J. D. (jj) Johnston

AES 2009 Audio Myths Workshop

Reply #13 –
Quote from: rpp3po on
Of course, an impediment could be that you may have better things to do.


My considered opinion is that I'm way, way too honest to get rich in the audio community.

I would suggest that Dick Pierce, Barry Blesser, FLoyd Toole, Louis Thebault, and Ethan are also in that situation... Just to name a few.
-----
J. D. (jj) Johnston

AES 2009 Audio Myths Workshop

Reply #14 –
I've split analog scott's responses confusing the decisions made at recording-time vs. the decisions made at playback-time here.

AES 2009 Audio Myths Workshop

Reply #15 –
JJ, can you explain what you meant by we should always dither?

AES 2009 Audio Myths Workshop

Reply #16 –
Quote from: hellokeith on
JJ, can you explain what you meant by we should always dither?

I'm sure JJ simply means that dither can never hurt when bit-reducing data, and can only help, so it should always be done since it's free.

--Ethan
I believe in Truth, Justice, and the Scientific Method

AES 2009 Audio Myths Workshop

Reply #17 –
I think I would further qualify the statement of dither never hurting.

The source material contains some amount of noise already. Sometimes the noise level is so low that you must add dither in order to avoid distortion when reducing the bit depth. Other times the noise level is high enough that it self-dithers, and the added dither increases the noise level negligibly.

There is a middle ground between these two extremes where these is enough noise that dither is not required to avoid distortion, but the noise is low enough that dither increases the total noise measurably. It is only in this very narrow range of inherent noise that dither should not be used. The likelyhood, however, of having just this amount of noise consistently across the entire clip is very small.

AES 2009 Audio Myths Workshop

Reply #18 –
Quote from: Ethan Winer on
Quote from: hellokeith on
JJ, can you explain what you meant by we should always dither?

I'm sure JJ simply means that dither can never hurt when bit-reducing data, and can only help, so it should always be done since it's free.

--Ethan



If you're not requantizing, "dither" does not exist.

If you are, it should happen.
-----
J. D. (jj) Johnston

AES 2009 Audio Myths Workshop

Reply #19 –
Quote from: pdq on
There is a middle ground between these two extremes where these is enough noise that dither is not required to avoid distortion, but the noise is low enough that dither increases the total noise measurably. It is only in this very narrow range of inherent noise that dither should not be used. The likelyhood, however, of having just this amount of noise consistently across the entire clip is very small.


Then there is still a philosophical question, is that noise part of the original, or not?

I argue that it is, and therefore should be dithered in order to capture the original source noise as faithfully as possible.
-----
J. D. (jj) Johnston

AES 2009 Audio Myths Workshop

Reply #20 –
Quote from: pdq on
I think I would further qualify the statement of dither never hurting.

The source material contains some amount of noise already. Sometimes the noise level is so low that you must add dither in order to avoid distortion when reducing the bit depth. Other times the noise level is high enough that it self-dithers, and the added dither increases the noise level negligibly.

There is a middle ground between these two extremes where these is enough noise that dither is not required to avoid distortion, but the noise is low enough that dither increases the total noise measurably. It is only in this very narrow range of inherent noise that dither should not be used. The likelyhood, however, of having just this amount of noise consistently across the entire clip is very small.


+1

The usual case with 16 bits and longer data words, is that the noise in the program material is way higher, a minium of 10 dB, and not uncommonly 40dB or more, than the LSB of the medium.

The history of my involvement with self-dither is a discussion with a well-known audio editor who is also a recordist. He published an article describing the characteristic sound quality of an analog tape that he recorded, as dithered using various dither settings provided by a certain Meridian product as he transcribed the tape to 16 bit digital. He would only distribute a 16 bit sample, and withheld the original 20 bit transcription.

If memory serves, the dynamic range of the recording was about 65 dB which is a pretty typical number for a live acoustic performance. Spectral analysis showed what appeared to be the noise floor of the room ("room tone"), overlaid with some mic/mic preamp noise,  overlaid with noise thqt appeared to be related to analog tape recording/playback. It was difficult to see anything that would be charactristic of the various dithering techniques that were used since they were in the range of 1 LSB, which is to say about 30 dB below the rest. 

This appeared to me to be  strong evidence that the strong audible differences that he claimed to hear probably lacked any physical cause that would be likely to be audible, even under the most ideal listening conditions.

At that point I realized that a quantizer no means for distinguishing the various noise sources summed together at its input. in fact it does not distinguish between signal and noise, but simply processes the bandwidth-limited F(t) regardless of where it comes from.

Needless to say several people whose products had been highly reviewed by said editor were more than happy to vigorously beat me about the head and shoulders for my insight. ;-)

AES 2009 Audio Myths Workshop

Reply #21 –
Quote from: Ethan Winer on
Quote from: Woodinville on
Especially at the source end, my position (which was said somewhere) is that you use what you want to get the sound you want. To the extent euphony is part of the desired target, it's simply part of the art, and arguing with personal taste is pointless.

That's my position too. My point with "high fidelity" from a recording perspective is you do whatever is needed to get the sound you want. Maybe you'll stick a microphone under the radiator, or run a singer's voice through an old tube guitar amp. Doesn't matter. But once you have the sound you want, then accuracy is what matters most, to preserve that sound intact. I make this point all the time in audio forums. I'll be talking about fidelity only, and some clown will say he likes the distorted sound he gets from pushing his preamp. Fine, but that's not what I was talking about!


BTW Ethan, is there any way to get a mpeg of the presentation?

AES 2009 Audio Myths Workshop

Reply #22 –
Quote from: Arnold B. Krueger on
The history of my involvement with self-dither is a discussion with a well-known audio editor who is also a recordist ... This appeared to me to be strong evidence that the strong audible differences that he claimed to hear probably lacked any physical cause that would be likely to be audible, even under the most ideal listening conditions.

LOL, indeed, and I know exactly who you mean.

Quote
BTW Ethan, is there any way to get a mpeg of the presentation?

I can mail you a DVD version of what's on YouTube if you email me your address. I can make either a DVD meant to play on a consumer DVD player, or a DVD-R with a 2 GB WMV file. Or do you mean the entire presentation? I do have that, but it's a 36 GB MPEG file. Someone else asked me for that by PM, and I told him to send me a USB drive and I'll copy the file and ship it back. It's way to much work for me to do that any other way.

--Ethan
I believe in Truth, Justice, and the Scientific Method

AES 2009 Audio Myths Workshop

Reply #23 –


Hello!

Non-lurker and first time poster here.

Some of you who go to the Womb forums may recognize my handle.  dwoz here.

SO...

there's been some discussion about us here, I see!  wonderful.  I would like to clear up a few points, or at least offer my view of them, if you all don't mind.

First off, the title of the thread over at the womb, where Ethan Winer's now-famous conjecture about the measurability and audibility of audio and the transparency of audio equipment, is titled "Pathetic".  Now, that might seem like a case of the womb taking a "piss" on Ethan, but for one interesting thing:  That thread title was created and CHOSEN BY ETHAN HIMSELF.  When I first saw the thread, I was sorely tempted to change it to something less incendiary, but I held my hand.

Secondly, It is most certainly Ethan who takes the hard tone.  The man has a distinctly passive-aggressive, denigrating tone in his replies, which is dripping with ad hominem, argument from authority, false association, and a whole slew of other deficiencies that would certainly never pass in person, in polite discourse.  And, because this is the internet, he is of course answered in kind.  Ethan minces no words in describing me and my opinions and thoughts, across the internet.  I afford him the same kindness he shows me.

And yes, at the Womb, we strive to be entertaining, engaging, and can at rare times even accomplish that.  The signal to noise is really quite high.  But that's just my opinion, now on to the salient points.

Ethan has made a number of related conjectures about audio.  It's measurability, how we may define transparency in an audio component, and a few "myths" that he claims to have debunked.

Now, I will say up front that there is nothing wrong with trying to do this...it's a laudable goal.  There is so much nonsense, crap, and outright fraud out there in the audio universe, that it boggles the mind!  Who could possibly be against a white knight riding in and trying to clean some of it up?   

Not me!  Good on you, Ethan, for trying to do that.

However....BAD FORM, Ethan, for being intellectually and technically sloppy in your work.  What could be worse, than a mythbuster that simply substitutes his own myth for the one he's debunking?

Ethan makes a classic and easy mistake in his assumptions, which is easily noticed if you have the intellectual honesty to simply look.  He makes a conjecture about the required measurements to fully and completely describe the fidelity of audio.  According to him, there's four.  Now, when you examine this supposition in the context of a home listening audio system, his conjecture, while incomplete and inaccurate, is nonetheless somewhat useful.

However...when you then try to take that same conjecture,and broadly apply it to the entire audio production process, it stops being simply a benignly-inaccurate useful tool, and becomes an outright falsehood that can have direct consequences to the resultant audio.

When pointed out to him, To his credit, he did re-qualify his statements somewhat.  But not to the community-at-large where he is promulgating his wares.

Let me reiterate:  he has been shown to be factually wrong on every single claim he's made.  He has thus shifted his argument away from absolute statements, to relativistic statements, where he treads in the very subjective waters that you here at hydrogenaudio seem to revile.  Instead of "stacking" of audio artifacts being non-existent, it is now "not audible in today's equipment".  Instead of 32 bit float computer math being "absolutely accurate" it is "accurate and precise to the extent of the implementation and optimization of the algorithm".  Instead of "phase doesn't matter", it is now "phase issues are not audible in today's equipment".  "Jitter is a non-issue" has become "jitter is a non issue in a properly implemented system".

Slippery slope, folks.  He's conceded on the points, now we're just haggling over price.

Now, to his credit...again, most of this stuff doesn't matter to the home listener, because MOST of the issues he's been wrong about, only rear their ugly heads when you set about combining and summing complex signals (such as when building a music mix), and are NOT problems that manifest in the reproduction-side.  For example, phase anomalies in speakers are, in fact, marginally if at all audible.  But a non-linear phase anomaly that exists in an A/D converter, will and does show up as frequency domain errors when signals are summed.  This is not a guess or theory on my part, but long-settled fact. 

So, I guess my diatribe here is about being intellectually rigorous when you try to do something about audiophile nonsense.  Don't simply substitute your own error for the one you're attacking.

As it happens, when James Johnson came over to debate ME about this, at the Womb, he essentially agreed with about 98% of what I said, but for some nitpicks on some incidentals.  He agrees with me. 

While I'm here, I may as well gore one of your sacred cows, and get myself on the "enemies" list.  DBT.  What a wonderfully mis-understood thing she is!  Double blind Tests are a great, wonderful technique.  But employ them within a poorly-designed test, and you will have bad data with high confidence.  Simply having a double blind test does not mean your results will mean ANYTHING.  This is another myth that needs debunking!

One more thing.  It is my firm and unyielding belief that if a signal can exist as a voltage within a system, it can be completely measured.  Therefore there will be no signal for which "my ears tell me something that the measurements can't".  Everything is measurable.  However, it is also my firm and unyielding belief that the measurements required to completely describe what the listener can hear, are a far different set than the ones that Ethan Winer is attempting to promulgate.

dwoz

AES 2009 Audio Myths Workshop

Reply #24 –
Quote from: dwoz on
While I'm here, I may as well gore one of your sacred cows, and get myself on the "enemies" list.

Too bad that discussion of DBT has always been allowed here. You're not a vigilante just yet.

Quote
DBT.  What a wonderfully mis-understood thing she is!  Double blind Tests are a great, wonderful technique.  But employ them within a poorly-designed test, and you will have bad data with high confidence.  Simply having a double blind test does not mean your results will mean ANYTHING.  This is another myth that needs debunking!

Eh? Who is actually arguing here the benefit of poorly designed tests? Or are you trying to set up a strawman?
"We cannot win against obsession. They care, we don't. They win."