Dynamic Wow and Flutter

[haraldo]

Hello all

On the AES convention, last Friday, there was a presentation about "Dynamic Wow and Flutter", as I understand this relates to a distortion form that has been discussed by amplifier designers for 30 years, but no-one has been able to pinpoint this property.....

The idea is that this is something brand new that will shed light on audible differences in electronics, things that up until now has not been measurable...

Is there anyone out there that can shed some light onto this subject?

 

[JerryLove]

Wow and flutter are pitch changes (a change in frequency). It is obvious on an osciliscope with a test tone, or via DSP on a more complex recording.

It was an issue with tapes and records because the speed that the media passed under the read device (magnet or needle) was not completely constant (for any number of reasons). It is not an amp problem.

Wow and flutter measurement - Wikipedia, the free encyclopedia

 

[Irvrobinson]

Hello all

On the AES convention, last Friday, there was a presentation about "Dynamic Wow and Flutter", as I understand this relates to a distortion form that has been discussed by amplifier designers for 30 years, but no-one has been able to pinpoint this property.....

The idea is that this is something brand new that will shed light on audible differences in electronics, things that up until now has not been measurable...

Is there anyone out there that can shed some light onto this subject?

I agree with Jerry, amps can't do this. Either would show up as distortion and be visible in an FFT plot, and it doesn't. There must be some misunderstanding.

The only amplifier distortion that's vaguely similar is latency that varies by frequency, and this manifests itself as phase change. Some amps even specify this, with a spec that reads something like +/- 20 degrees. There's some controversy in the audiophile world about whether or not phase distortion is audible.

 

[haraldo]

Gentlemen, sorry to say but you're completely off topic

Dynamic wow and flutter exists in all amplification components and as I understand the leading designers of amplifiers are trying to understand what this is, nothing to do with "wow and flutter"

Ignoring something and saying it doesn't exist because you don't know about it is not the way to go, I think.....

 

[Irvrobinson]

Oh really? I have been following amplifier design discussions in various forums for about 30 years, and I've never heard of dynamic wow and flutter. Wow and flutter are terms with very specific meanings for analog tape, and in the case of wow for turntables, that have nothing to do with how amplifiers operate. How about you educate us on what, exactly, this term means?

As for explaining the audible differences between electronics, it is controversial that there are any audible differences between properly designed and functioning amplifiers, so the notion that there's this new theory that will miraculously explain the audible differences smacks of snake oil. Can you quote from this AES presentation?

 

[haraldo]

Oh really? I have been following amplifier design discussions in various forums for about 30 years, and I've never heard of dynamic wow and flutter. Wow and flutter are terms with very specific meanings for analog tape, and in the case of wow for turntables, that have nothing to do with how amplifiers operate. How about you educate us on what, exactly, this term means?

As for explaining the audible differences between electronics, it is controversial that there are any audible differences between properly designed and functioning amplifiers, so the notion that there's this new theory that will miraculously explain the audible differences smacks of snake oil. Can you quote from this AES presentation?

This is something John Curl posted in another location, the term of Dynamic wow and flutter was first stated last Friday

As far as I understand so far, this is so complicated and hard to understand that even the most clever people around here do have big difficulties explaining, even comprehending this.....

I initiated this thread to see if anyone would have some useful info, seems like it's a waste of time..... I believe there are many self proclaimed experts around here, sometimes it's actually useful to have an open mind, you should try this sometimes.... Probably better to just buy the AES papers.....

I find it funny the notion that all amplifiers sound the same..... LOL

 

[Irvrobinson]

This is something John Curl posted in another location, the term of Dynamic wow and flutter was first stated last Friday

I initiated this thread to see if anyone would have some useful info, seems like it's a waste of time..... I believe there are many self proclaimed experts around here.... Probably better to just buy the AES papers.....

Self-proclaimed experts? Not at all, but if you're thinking you can post some revelation about possible explanations for audible differences between electronics, regarding some new and heretofore undetected distortion, with a very confusing name, and you're not going to get some skepticism, you have unrealistic expectations. And the topic has been discussed for 30 years, but the term is new?

Have you read the AES paper? I just searched for it, no luck.

 

[Irvrobinson]

I find it funny the notion that all amplifiers sound the same..... LOL

You can LOL all you want, but it is very difficult to prove there are any audible differences between properly engineered amplifiers operating within their power constraints. And I say that as someone who *is* skeptical that all amplifiers sound exactly the same.

 

[haraldo]

Self-proclaimed experts? Not at all, but if you're thinking you can post some revelation about possible explanations for audible differences between electronics, regarding some new and heretofore undetected distortion, with a very confusing name, and you're not going to get some skepticism, you have unrealistic expectations. And the topic has been discussed for 30 years, but the term is new?

Have you read the AES paper? I just searched for it, no luck.

You have a chance to learn something new now

Yes I realize I have unrealistic expectations posting questions here and expect to get any good answers......

 

[3db]

Hello all

On the AES convention, last Friday, there was a presentation about "Dynamic Wow and Flutter", as I understand this relates to a distortion form that has been discussed by amplifier designers for 30 years, but no-one has been able to pinpoint this property.....

The idea is that this is something brand new that will shed light on audible differences in electronics, things that up until now has not been measurable...

Is there anyone out there that can shed some light onto this subject?

I'm also in the skeptical camp on this one. Perhaps a definition of dynamic wow and flutter would help us to understand this. Like Jerry said, the standard definition for wow and flutter revolves around inconsistent mechanical speed whether it be a tape drive or a turntable. Amplifiers have no mechanical parts in them so I fail to comprehend this. Lets get some definitions around this term.

 

[jcl]

I looked through the AES calendar but didn't find anything regarding 'Wow & flutter'. However I did find this session 'P5-1 Measurement of Harmonic Distortion Audibility Using a Simplified Psychoacoustic Model' here AES San Francisco 2012 » Paper Session P5: Measurement and Models
The description begins as -
'A perceptual method is proposed for measuring harmonic distortion audibility. This method is similar to the CLEAR (Cepstral Loudness Enhanced Algorithm for Rub & buzz) algorithm previously proposed by the authors as a means of detecting audible Rub & Buzz, which is an extreme type of distortion [1,2].'

Is this perhaps the session you are referring to?

 

[mtrycrafts]

Hello all

On the AES convention, last Friday, there was a presentation about "Dynamic Wow and Flutter", as I understand this relates to a distortion form that has been discussed by amplifier designers for 30 years, but no-one has been able to pinpoint this property.....

The idea is that this is something brand new that will shed light on audible differences in electronics, things that up until now has not been measurable...

Is there anyone out there that can shed some light onto this subject?

I wonder who those amp designer were/are
And, not sure which electronic components have audible differences, of course not including speakers, TT, SET and such

Who was the presenter?

Also, don't forget, conference papers and presentations don't get peer reviewed like a journal paper would. This would not be the 1st time silly stuff got presented. 1991 conference was full of it.

 

[markw]

I just did a search and, aside from some rock band, the only references I can find relate to mechanical reproduction devices such as tape recorders and turntables.

Haraldo, could you please provide some links as to what you're refering to?

Maybe that would help clarify this issue.

 

[haraldo]

I wonder who those amp designer were/are
And, not sure which electronic components have audible differences, of course not including speakers, TT, SET and such

Who was the presenter?

Also, don't forget, conference papers and presentations don't get peer reviewed like a journal paper would. This would not be the 1st time silly stuff got presented. 1991 conference was full of it.

From what I read in other forums it's claimed to be well known in industry for 30 years but noone ever been able to pinpoint, demonstrate or provide measurable proof of these issues.

The paper in question is the following:
P7-3 'Further Testing and Newer Methods in Evaluating Amplifiers for Induced Phase and Frequency Modulations via Tones, Amplitude Modulated Signals and Pulsed Waveforms' by Ron Quan Convention Paper # 8722

AES San Francisco 2012 » 133rd Convention

I tried to locate the paper for purchasing but could not find a way to get hold of it.

John Curl posted in linkedin forum:
"This is just another facet of this 'no win' debate. For the record, NOBODY has a baseline on how much 'FM distortion' is audible. It has been denied, suppressed, and ignored for more than 30 years, when Matti Otala first postulated it.
To understand FM distortion, think of FM modulation vs AM modulation, which is what we usually measure with our test equipment. It is NOT easily measurable, unless it is generated in large amounts, or special test equipment is designed and built for the purpose. Trust me, in a few years, there will be a very standard, FM distortion test incorporated in standard test equipment. Just not yet."

 

[Irvrobinson]

From what I read in other forums it's claimed to be well known in industry for 30 years but noone ever been able to pinpoint, demonstrate or provide measurable proof of these issues.

The paper in question is the following:
P7-3 'Further Testing and Newer Methods in Evaluating Amplifiers for Induced Phase and Frequency Modulations via Tones, Amplitude Modulated Signals and Pulsed Waveforms' by Ron Quan Convention Paper # 8722

AES San Francisco 2012 » 133rd Convention

I tried to locate the paper for purchasing but could not find a way to get hold of it.

John Curl posted in linkedin forum:
"This is just another facet of this 'no win' debate. For the record, NOBODY has a baseline on how much 'FM distortion' is audible. It has been denied, suppressed, and ignored for more than 30 years, when Matti Otala first postulated it.
To understand FM distortion, think of FM modulation vs AM modulation, which is what we usually measure with our test equipment. It is NOT easily measurable, unless it is generated in large amounts, or special test equipment is designed and built for the purpose. Trust me, in a few years, there will be a very standard, FM distortion test incorporated in standard test equipment. Just not yet."

Well, this is mostly over my head, but it smells like yet another attempt at proving how negative feedback is bad for amplifiers. Maybe I'm wrong, but I smell it.

 

[haraldo]

Well, this is mostly over my head, but it smells like yet another attempt at proving how negative feedback is bad for amplifiers. Maybe I'm wrong, but I smell it.

From what I believe, You're wrong on this.....

And in which was is negative feedback not bad for amplifiers?

 

[3db]

From what I believe, You're wrong on this.....

And in which was is negative feedback not bad for amplifiers?

Please find us a defintion. For as it stands now, it makes no sense at all. I aloso have a very difficult time believing that something as simple as amplifiers cannot have this problem that is proportedly 30 years old solved by now. No offense to you but I'm getting the sense that this rubbish and left overs from the audiophools.

 

[jinjuku]

Haraldo could you make some form of mission statetment as to your starting of this thread and your posting style thereof?

Simply asking this as a fellow poster and am curious as to what you are getting at. Is there a particular target that you are trying to hit?

 

[jinjuku]

From what I believe, You're wrong on this.....

And in which was is negative feedback not bad for amplifiers?

So are you saying that only amplifiers that employ zero feedback designs are optimal designs?

 

[haraldo]

Haraldo could you make some form of mission statetment as to your starting of this thread and your posting style thereof?

Simply asking this as a fellow poster and am curious as to what you are getting at. Is there a particular target that you are trying to hit?

Hi, as there are so many AES members here, I would be curious if someone would have any useful input....

As far as I understand this AES paper goes into detail about FM distortion artifacts that's been more or less known to be an issue for a long time, but never been addressed or never been measurable, but still audible to the human ear, this kind of distortion will be neglectable by those who only rely on the measuring equipment and say that the measurements present the only and whole truth.

I believe there's much more to amplifier technology and what makes a difference, than what's known so far.... If we close our eyes and say that we know everything we need to know audio technology will not get further but come to a standstill...

Much of the measurements that we have today was developed as a result of audible distortion properties that we were unable to explain and as such not measure, so new theories were developed and new measurement techniques and standards were developed. I'm no expert on this but it's what I read from a some respected amplifier designers, although.... I don't think this fact can be challenged.....

I think there's much more to amplifier technology and audibility of different distortion mechanisms than what we know today, but I can't prove anything.... but if we close our eyes we will not advance....

Now it's time for you guys to roll the sabers....