Is there any chance that even the best measuring DACs have a specific (house) sound?

[Blumlein 88]

Isn't there any audio software/hardware that can take the output from two different dacs and compare it?

Deltawave by Pkane who is a member here. Get your own free fully functional copy here.

DeltaWave Audio Null Comparator | DeltaWave documentation

deltaw.org

As further comment this is sophisticated nulling software. Results show what corrupts nulling the most among good DACs is differing phase response in the upper frequency ranges. This comes from the differing filters. What is known about this indicates humans do not find phase differences in upper frequencies to be audible. The software above can even fix that for you in a comparison and once you do good measuring DACs simply don't result in very much residual difference of any level that could be heard.

If good measuring DACs sound different I would say it will be in the filtering. Everything else is beyond reproach in terms of audibility.

 

[Garrincha]

Deltawave by Pkane who is a member here. Get your own free fully functional copy here.

DeltaWave Audio Null Comparator | DeltaWave documentation

deltaw.org

As further comment this is sophisticated nulling software. Results show what corrupts nulling the most among good DACs is differing phase response in the upper frequency ranges. This comes from the differing filters. What is known about this indicates humans do not find phase differences in upper frequencies to be audible. The software above can even fix that for you in a comparison and once you do good measuring DACs simply don't result in very much residual difference of any level that could be heard.

If good measuring DACs sound different I would say it will be in the filtering. Everything else is beyond reproach in terms of audibility.

This is by far the most interesting and constructive answer given so far.

 

[Blumlein 88]

Is it really that difficult to be polite and not condescending? No this is not a thread about these issues, it is just a question that came up as well. IMD were only introduced in the 70s, as far as I know. Before people probably thought that harmonic distortions offer the full picture. In science and engineering is always room for something new. If you really know it all so well, is it so difficult to explain it in well phrased arguments? And if you are bothered by theses discussions, why do you not simply stay away and remain silent?

Here is a screen shot from Audio magazine in 1949 testing a triode amp. Notice the graph of IMD vs level. IMD has been known for a long, long time. https://worldradiohistory.com/Archive-All-Audio/Archive-Audio/40s/Audio-1949-02.pdf

Intermodulation distortion testing was first adopted in the U.S. as a practical procedure in the motion picture industry in 1939 by the Society of Motion Picture Engineers (SMPE -- no "T" [television] yet) and made into a standard in 1941.

Above quoted from this page:

Audio Specifications

To understand specifications, you must understand the tests. This note describes audio tests used to characterize audio performance with conditions.

www.ranecommercial.com

Meaning it had been known at least prior to 1939 when they decided to write a standard for the testing.

 

[tonycollinet]

Is it really that difficult to be polite and not condescending? No this is not a thread about these issues, it is just a question that came up as well. IMD were only introduced in the 70s, as far as I know. Before people probably thought that harmonic distortions offer the full picture. In science and engineering is always room for something new. If you really know it all so well, is it so difficult to explain it in well phrased arguments? And if you are bothered by theses discussions, why do you not simply stay away and remain silent?

The 70's are 50 years in the past now. I know that because I was there

Prior to the 70's, HIFI as we think of it now basically didn't exist. Or at least simple harmonic distortion was so significant as to render IMD irrelevant to many. Don't think that because it wasn't measured it wasn't known about.

Audio frequncy is (compared to most areas of electroincs) pretty easy to understand, and has been well understood for 100 years or more. Transmission line theory for example was developed for the need for long range telegraph signalling (read: morse code and the like), in the second half of the 1800's FFS.

There are not going to be sudden new discoveries that explain people hearing differences between audibly identical electronics that isn't already explained by the very well understood psycho acoustic phenomena such as perception bias.

 

[Garrincha]

The 70's are 50 years in the past now. I know that because I was there

Prior to the 70's, HIFI as we think of it now basically didn't exist. Or at least simple harmonic distortion was so significant as to render IMD irrelevant to many. Don't think that because it wasn't measured it wasn't known about.

Audio frequncy is (compared to most areas of electroincs) pretty easy to understand, and has been well understood for 100 years or more. (Transmission line theory for example was developed for the need for long range telegraph signalling (read: morse code and the like), in the second half of the 1800's FFS.

There are not going to be sudden new discoveries that explain people hearing differences between audibly identical electronics that isn't already explained by the very well understood psycho acoustic phenomena such as perception bias.

While you might be correct about electronics, I wouldn´t be so sure about psycho acoustics, since as far as I know, many basic phenomena are not properly understood already.

 

[Blumlein 88]

While you might be correct about electronics, I wouldn´t be so sure about psycho acoustics, since as far as I know, many basic phenomena are not properly understood already.

There could be unknown interactions of various kinds. There almost surely is. Just as surely there is more well worked out information on the primary ways hearing works than most people realize. Further in terms of an electrical signal there is amplitude, frequency and phase (and noise). There is nothing else, and we can measure all these to extreme precision. So we can measure two devices and see how the electrical signal differs even if we don't know all possible interactions psycho-acoustically. When the difference in two devices is buried in the thermal noise there is no place for the difference to be in those devices. Now not all devices are so perfect, but quite a few come very close, close enough it is difficult to see an audible difference is possible. Real significant differences are in transducers....microphones, headphones and speakers.

 

[Garrincha]

Here is a screen shot from Audio magazine in 1949 testing a triode amp. Notice the graph of IMD vs level. IMD has been known for a long, long time. https://worldradiohistory.com/Archive-All-Audio/Archive-Audio/40s/Audio-1949-02.pdf

View attachment 205688
Intermodulation distortion testing was first adopted in the U.S. as a practical procedure in the motion picture industry in 1939 by the Society of Motion Picture Engineers (SMPE -- no "T" [television] yet) and made into a standard in 1941.

Above quoted from this page:

Audio Specifications

To understand specifications, you must understand the tests. This note describes audio tests used to characterize audio performance with conditions.

www.ranecommercial.com

Meaning it had been known at least prior to 1939 when they decided to write a standard for the testing.

Thanks, interesting, I came across an article by Leinonen and Otala and gained the impression that they had introduced the concept, so that was wrong.

 

[Triliza]

That is exactly the job that @amirm 's Audio Precision analyser does. Really Really well.

Deltawave by Pkane who is a member here. Get your own free fully functional copy here.

Exactly, that was the point I was trying to make, things can be measured and there isn't much to wonder about. If there is something that cannot yet be measured or understood from a psycho acoustics point of view, it will not be present as a difference in dacs that measure well, because the people that design them do so based on the science that is available atm. If there is a breakthrough, the PR would surely let us know about it.

 

[Jimbob54]

Is it really that difficult to be polite and not condescending? No this is not a thread about these issues, it is just a question that came up as well. IMD were only introduced in the 70s, as far as I know. Before people probably thought that harmonic distortions offer the full picture. In science and engineering is always room for something new. If you really know it all so well, is it so difficult to explain it in well phrased arguments? And if you are bothered by theses discussions, why do you not simply stay away and remain silent?

Because, as I said in post number 2, we have been round this many many times, so why spin the wheel again? No point or argument you or I make will add anything to the overall discussion.

However, as Adam has reopened the thread, I'll stop banging my head against the brick wall and depart.

 

[Blumlein 88]

Thanks, interesting, I came across an article by Leinonen and Otala and gained the impression that they had introduced the concept, so that was wrong.

That is a slightly different animal. Transient IMD. Some early transistor designs tripped up on this. It is easily designed around and not really a problem. Here is a very good explanation down the middle of this page.

Intermodulation Distortion

Intermodulation Distortion (IMD)

sound-au.com

 

[tonycollinet]

Exactly, that was the point I was trying to make, things can be measured and there isn't much to wonder about. If there is something that cannot yet be measured or understood from a psycho acoustics point of view, it will not be present as a difference in dacs that measure well, because the people that design them do so based on the science that is available atm. If there is a breakthrough, the PR would surely let us know about it.

Psycho acoustics is what goes on in the brain sometimes independent of the sound waves hitting your ears. People can hear differences for reasons other than the physical sound being different. Psycho acoustics has nothing to do with "stuff we don't understand about sound waves"

And no - we can't measure all of what goes on in the brain. But we can control for it. It is why the double blind test is used.

Medical trials routinely use double blind testing because peoples response to treatment is known to be influenced by what they know about the treatment. It is the same for audio. It is known that people hear differences that don't physically exist, for a variety of reasons.

 

[AdamG247]

Because, as I said in post number 2, we have been round this many many times, so why spin the wheel again? No point or argument you or I make will add anything to the overall discussion.

However, as Adam has reopened the thread, I'll stop banging my head against the brick wall and depart.

As long as the conversation remains rooted in the science and engineering, revisiting some topics is fine. We have to find ways to allow the new members to explore these topics. I get where your coming from and that was why I initially closed the thread. To @Garrincha ’s credit he reached out to me and convinced me his interest is legitimate and constructive. He also made me realize if we close every topic we have already discussed, we might have very few active threads! . There can be new information disclosures or new and creative ways to explain the complexities of Audio Science that may be more meaningful to some. Like going through the pockets of your dirty jeans before tossing in the washing machine. You think you emptied them when you took them off?

 

[Garrincha]

As long as the conversation remains rooted in the science and engineering, revisiting some topics is fine. We have to find ways to allow the new members to explore these topics. I get where your coming from and that was why I initially closed the thread. To @Garrincha ’s credit he reached out to me and convinced me his interest is legitimate and constructive. He also made me realize if we close every topic we have already discussed, we might have very few active threads! . There can be new information disclosures or new and creative ways to explain the complexities of Audio Science that may be more meaningful to some. Like going through the pockets of your dirty jeans before tossing in the washing machine. You think you emptied them when you took them off?

Thanks Adam, I already got valuable insights. And yes, somebody who knows (or claims to know) everything already might very well abstain from the discussion.

 

[dominikz]

IMD were only introduced in the 70s, as far as I know. Before people probably thought that harmonic distortions offer the full picture.

IMD and HD are actually the result of the same non-linearity in the system transfer function.
The difference is that to measure HD you use a single frequency tone as input, and to measure IMD you use dual- or multi-tone input signal.
Knowing the exact transfer function of a system you can actually calculate the output for any input, and mathematically show how IMD or HD components are born in the system Of course we mostly don't have a transfer function model of real devices available.
So in a sense, by measuring HD you can to a degree predict device IMD performance as well. This is why THD is considered such an important measurement - even if music content input in reality generates distortion products more similar to IMD than HD.

But on a wider topic of this thread: before it makes sense to search for technical causes of different "DAC house-sounds" (or measurements showing it), we should determine first if there are indeed audible differences between devices being compared that need explaining.
To establish if there are audible differences between any two devices we just need a controlled listening test - not measurements.
In case of well-measuring DACs such listening tests that I've seen (and done) seem to show no significant audible differences - therefore it makes no sense to look for proof of audibility in the measurements.

Just my 2c!

EDIT: Note that in this post I'm using the term "transfer function" for a function describing the relationship between output signal amplitude vs input signal amplitude - sometimes also called "transfer curve". Not to be mistaken by the amplitude/phase vs frequency transfer function from Fourier/Laplace analysis of LTI systems.

 

[tonycollinet]

IMD and HD are actually the result of the same non-linearity in the system transfer function.
The difference is that to measure HD you use a single frequency tone as input, and to measure IMD you use dual- or multi-tone input signal.
Knowing the exact transfer function of a system you can actually calculate the output for any input, and mathematically show how IMD or HD components are born in the system Of course we mostly don't have a transfer function model of real devices available.
So in a sense, by measuring HD you can to a degree predict device IMD performance as well. This is why THD is considered such an important measurement - even if music content input in reality generates distortion products more similar to IMD than HD.

But on a wider topic of this thread: before it makes sense to search for technical causes of different "DAC house-sounds" (or measurements showing it), we should determine first if there are indeed audible differences between devices being compared that need explaining.
To establish if there are audible differences between any two devices we just need a controlled listening test - not measurements.
In case of well-measuring DACs such listening tests that I've seen (and done) seem to show no significant audible differences - therefore it makes no sense to look for proof of audibility in the measurements.

Just my 2c!

This. So Much This.

If you believe you can hear the difference between two well measuring Dacs, prove it by gettting a statistically relevant result in a controlled double blind test - then we'll have something to talk about.

 

[SIY]

Here's a clue: not once, never, ever, has ANYONE shown that they could distinguish between two competent DACs (99.9% of them) when using ears only. No peeking, matched levels.

When the day comes along that someone demonstrates audibility when measurements show there shouldn't be, then the matter is worth discussing. So far... nothing. Just empty claims devoid of any actual evidence. For decades.

 

[sonitus mirus]

Here's a clue: not once, never, ever, has ANYONE shown that they could distinguish between two competent DACs (99.9% of them) when using ears only. No peeking, matched levels.

When the day comes along that someone demonstrates audibility when measurements show there shouldn't be, then the matter is worth discussing. So far... nothing. Just empty claims devoid of any actual evidence. For decades.

That should be enough for many of us to just go enjoy listening to our music.

 

[diddley]

there is a wonderfull search engine in this forum so that you can search back and don't have double threads.my 2c.
I am of too.

 

[Garrincha]

IMD and HD are actually the result of the same non-linearity in the system transfer function.
The difference is that to measure HD you use a single frequency tone as input, and to measure IMD you use dual- or multi-tone input signal.
Knowing the exact transfer function of a system you can actually calculate the output for any input, and mathematically show how IMD or HD components are born in the system Of course we mostly don't have a transfer function model of real devices available.
So in a sense, by measuring HD you can to a degree predict device IMD performance as well. This is why THD is considered such an important measurement - even if music content input in reality generates distortion products more similar to IMD than HD.

But on a wider topic of this thread: before it makes sense to search for technical causes of different "DAC house-sounds" (or measurements showing it), we should determine first if there are indeed audible differences between devices being compared that need explaining.
To establish if there are audible differences between any two devices we just need a controlled listening test - not measurements.
In case of well-measuring DACs such listening tests that I've seen (and done) seem to show no significant audible differences - therefore it makes no sense to look for proof of audibility in the measurements.

Just my 2c!

EDIT: Note that in this post I'm using the term "transfer function" for a function describing the relationship between output signal amplitude vs input signal amplitude - sometimes also called "transfer curve". Not to be mistaken by the amplitude/phase vs frequency transfer function from Fourier/Laplace analysis of LTI systems.

I agree and am fully convinced of the validity and strength of double blind listening tests, but my question aims in the other direction. What measurement results must be given to (with almost certainty) conclude that there can not be any audible differences.

 

[tonycollinet]

I agree and am fully convinced of the validity and strength of double blind listening tests, but my question aims in the other direction. What measurement results must be given to (with almost certainty) conclude that there can not be any audible differences.

I think you have been pretty comprehensively answered. If you disagree, you can relatively easily prove it to yourself with the blind test.