[SoundAndMotion]

Well, this is a strange thread.
Some, mostly haiku and bilboda, state that they believe playback of FLAC files "on-the-fly" could sound different from WAV or pre-decompressed FLACs. They never state that they think the PCM data going to the DAC or bits are different or corrupted. Yet nearly all responses to them center on the fact that the bits are the same! I don't think this is a deliberate straw man, rather a simple misunderstanding... or at least I hope that's the case.

I can think of 3 possible ways that the sound can be different.

Please don't ignore my use of the word ”possible”. I am answering those who say "impossible", "never" or "always". I don't think anyone here can speak with authority about the likelihood or probabilities of certain problems w.r.t. all devices that may be currently in use. I know I can't.

First, problems in the speed of the algorithms, whether hardware, software or both. The fact that your desktop quad i7 can solve complex systems of equations in real time does not make a <$10 FLAC player run faster. Granted, most weak processors either won't play a FLAC -8 file or will cause audible clicks or stuttering, and some here have labeled that “broken”, but they’re not illegal, so they exist. But if longer gaps or delays (>10ms) create such artifacts, what about shorter gaps or delays that occur periodically?
I was curious, so I created a program that inserts a selectable number of zeroes or fixed values (zero order hold) every so often (set or variable period of time). Quick summary: some combinations were clearly audible, while others were inaudible to me. Intermediate values produce varying degrees of degradation. I wonder whether a degradation that isn’t obvious, can perhaps be ABX-able and simply sound “better”. Does this mimic a too-slow process? I don’t know. Do you?
 
Second, simple software/firmware bugs, other than time-inefficiency. They exist and when a clear problem presents (e.g. doesn’t play or no sound), they get fixed. But if a small, simple, non-fatal math error occurs, is it guaranteed that it will be found?
Before you claim these don’t exist, or at least not any more, google: flac playback problems. Recent biggies include Android 4.4 (Kit Kat - 2013) and VLC 2.2.0 (2015).
 
And finally, analog noise, dependent on processor “effort”. Assuming that this noise is not severe enough to disturb the digital bits in the signal path (good assumption, I think), the idea is additional current draw from an active vs. nearly idle CPU could find its way to the post-D/A-conversion side of the path. This idea is the most speculative. Although analog noise from USB data has been shown on DAC outputs (mostly the 8kHz microframe noise), it has been very low level. But it demonstrates the concept, and makes the claims of "impossible", "never" or "always" unnecessarily risky. I think “unusual”, “rare” and “typically” would be better choices.
 
I suspect that reports of hearing differences often occur when there actually is none, but to state that it cannot occur is not true.

 

[Brooko]

Great - find a real world example where the difference actually exists, and is actually audible - and then we can take your theory further 

 

[SoundAndMotion]

  Great - find a real world example where the difference actually exists, and is actually audible - and then we can take your theory further 

Android 4.4 and VLC 2.2.0 are real-world. And I have no theory, just pointing out that the ideas are not impossible.
 
Also, I understand the burden of proof lies with the claimant. But do you understand that no one (especially me) plans to test all devices/software/etc. out there?
 
I can show that the type of problem that I believe causes stuttering does degrade sound, when less severe. It is speculative though!

 

[Ruben123]

Any good device will still not stutter though. And stutter is not the same as "loss of sound stage, instrument separation and high frequency detail". My 1996 pentium one can play highest compression flac without any problem and so does my $6 Chinese player. It may be in the software though, but that doesn't mean the file sounds different, but your player is incapable. And it should stutter, but let's be fair: all audiophile improvements "sound the same", be it a cable or leather case.

 

[Uberclocked]

  Well, this is a strange thread.
Some, mostly haiku and bilboda, state that they believe playback of FLAC files "on-the-fly" could sound different from WAV or pre-decompressed FLACs. They never state that they think the PCM data going to the DAC or bits are different or corrupted. Yet nearly all responses to them center on the fact that the bits are the same! I don't think this is a deliberate straw man, rather a simple misunderstanding... or at least I hope that's the case.

I can think of 3 possible ways that the sound can be different.

Please don't ignore my use of the word ”possible”. I am answering those who say "impossible", "never" or "always". I don't think anyone here can speak with authority about the likelihood or probabilities of certain problems w.r.t. all devices that may be currently in use. I know I can't.

First, problems in the speed of the algorithms, whether hardware, software or both. The fact that your desktop quad i7 can solve complex systems of equations in real time does not make a <$10 FLAC player run faster. Granted, most weak processors either won't play a FLAC -8 file or will cause audible clicks or stuttering, and some here have labeled that “broken”, but they’re not illegal, so they exist. But if longer gaps or delays (>10ms) create such artifacts, what about shorter gaps or delays that occur periodically?
I was curious, so I created a program that inserts a selectable number of zeroes or fixed values (zero order hold) every so often (set or variable period of time). Quick summary: some combinations were clearly audible, while others were inaudible to me. Intermediate values produce varying degrees of degradation. I wonder whether a degradation that isn’t obvious, can perhaps be ABX-able and simply sound “better”. Does this mimic a too-slow process? I don’t know. Do you?
 
My Sansa C250V2 that I got for $10 in 2008 plays FLAC files fine through Rockbox.  Distortion will only happen if there's something wrong with the decoding.
 
Second, simple software/firmware bugs, other than time-inefficiency. They exist and when a clear problem presents (e.g. doesn’t play or no sound), they get fixed. But if a small, simple, non-fatal math error occurs, is it guaranteed that it will be found?
Before you claim these don’t exist, or at least not any more, google: flac playback problems. Recent biggies include Android 4.4 (Kit Kat - 2013) and VLC 2.2.0 (2015).
 
The issues with VLC and Android 4.4 occur as an inability to play FLAC files and audible chirps/skips/stuttering.
 
And finally, analog noise, dependent on processor “effort”. Assuming that this noise is not severe enough to disturb the digital bits in the signal path (good assumption, I think), the idea is additional current draw from an active vs. nearly idle CPU could find its way to the post-D/A-conversion side of the path. This idea is the most speculative. Although analog noise from USB data has been shown on DAC outputs (mostly the 8kHz microframe noise), it has been very low level. But it demonstrates the concept, and makes the claims of "impossible", "never" or "always" unnecessarily risky. I think “unusual”, “rare” and “typically” would be better choices.
 
This may be happening with my Sansa C250V2.  However, it manifests more as a hissing noise and clicks/chirps/something else.  Terrible shielding.  You can literally hear the sorting algorithm used when compiling a database.
 
I suspect that reports of hearing differences often occur when there actually is none, but to state that it cannot occur is not true.

 

[SoundAndMotion]

...Granted, most weak processors either won't play a FLAC -8 file or will cause audible clicks or stuttering, and some here have labeled that “broken”, but they’re not illegal, so they exist. But if longer gaps or delays (>10ms) create such artifacts, what about shorter gaps or delays that occur periodically?
I was curious, so I created a program that inserts a selectable number of zeroes or fixed values (zero order hold) every so often (set or variable period of time). Quick summary: some combinations were clearly audible, while others were inaudible to me. Intermediate values produce varying degrees of degradation. I wonder whether a degradation that isn’t obvious, can perhaps be ABX-able and simply sound “better”.

 

And stutter is not the same as "loss of sound stage, instrument separation and high frequency detail".

...It may be in the software though, but that doesn't mean the file sounds different, but your player is incapable. And it should stutter, ...

 

The issues with VLC and Android 4.4 occur as an inability to play FLAC files and audible chirps/skips/stuttering.

 
3 quickies:
-I don't believe that playback is either perfect or audible stuttering [long gaps(>10ms) fairly infrequently(>300ms)]
are the only audible alternative. Intermediate flaws sound degraded without stuttering.
-I don't know what colorful words would be used to describe such degradation.
-No one has said the file sounds different, only playback (with "insufficient" hardware/software).

 

[castleofargh]

let's do things in the proper order for once.
1/ first notice a difference. plenty of people to talk about that on any subject, even alien stuff, so we're clear on that one. 
2/ confirm there really is a difference through testing. most of the feedbacks from people noticing differences come with no such evidence.so we can just stop right there.
3/ when we can see several cues that there are indeed differences, maybe we can try figuring out what it's linked to. like if it's a software's fault, or a noisy computer, or whatever reason I can't think about because I don't know of it. and then move on to try and confirm those hypothesis. who knows maybe in the end we'll get a proper conclusion.
 
in short, anything looking just a little like a scientific method. or a rational method at least.
 
 

 

Spoiler: the bad way

because what I keep seeing is more like this:
-I think I heard stuff.
-therefore I know I heard stuff
-therefore I can make general claims of causality for no reason and cherry pick whatever objective data that will seem to work with my empty claim.
   
  I don't know about you guys, but I really don't want to see that kind of stuff. like at all.

 
 
so I just went to record foobar playing the RMAA test file, and a flac version of it recorded with audacity using virtual audio cable to go directly from one to the other. I didn't care to try and get the best measurements, everything is at 16/44 even VAC and audacity. I just cared to have twice the same conditions with good enough values for audible concerns).
the flac version was converted with basic default foobar conversion at 5, no dither. I really didn't try to be fancy here. just trying to remove as many things as possible so that I'm left with the computer processing and the formats. so I'm not testing for everything, only that.
I did 2 runs at different times with firefox and several tabs opened, so my typical way of listening to music on that laptop.
 

I fail to see a reason to suspect anybody would get an audible difference out of this. and I don't feel like I'm hearing one(with music, because listening to RRMA test file isn't a lot of fun^_^).  my anecdotal perspective is that if flac can sound different from calculation errors or codec mistakes, it didn't seem to do so on my computer while testing.
 
I haven't done the same thing in a loop involving a DAC and ADC, because I seem to have misplaced my focusrite ATM. but I'm not holding my breath on that system.

 

[SoundAndMotion]

Sometimes it's amusing, sometimes frustrating, sometimes annoying...

let's do things in the proper order for once.
....
in short, anything looking just a little like a scientific method. or a rational method at least.

...getting lectured on how to do science.

A step you forgot was "sanity testing". That is what most of the posts here did. Can it happen? Is it possible? Most said "no, impossible". My response to the sanity testing stage is: it is possible, perhaps unlikely, but possible.

Your test is very inefficient. Just going out yourself and searching for the effect shows results only for your setup. It is easy to argue that is not the general case. An important part of setting up an experiment is preparing to argue that the results can generalize. (And be honest: you don't believe it's possible, do you?)

It may well be true that either it plays perfectly *OR* it stutters *OR* it doesn't play at all. I'm not convinced that anyone has shown that, so I remain open to the possibilities I described. Not convinced!!, but open.

 

[Brooko]

And that is where I leave this thread.  If you're not going to engage properly - "I think, I feel, I believe" - in an actual science thread?
 
I'll go back to my original question - which of course you won't answer: "find a real world example where the difference actually exists, and is actually audible"
 
In other words - I want two files from the same master - where there is an audible difference after volume matching - one FLAC, one WAV
 
Remember the actual topic of the thread?
 
Sanity check? [shakes head, walks away]

 

[castleofargh]

Sometimes it's amusing, sometimes frustrating, sometimes annoying...

let's do things in the proper order for once.
....
in short, anything looking just a little like a scientific method. or a rational method at least.

...getting lectured on how to do science.

A step you forgot was "sanity testing". That is what most of the posts here did. Can it happen? Is it possible? Most said "no, impossible". My response to the sanity testing stage is: it is possible, perhaps unlikely, but possible.

Your test is very inefficient. Just going out yourself and searching for the effect shows results only for your setup. It is easy to argue that is not the general case. An important part of setting up an experiment is preparing to argue that the results can generalize. (And be honest: you don't believe it's possible, do you?)

It may well be true that either it plays perfectly *OR* it stutters *OR* it doesn't play at all. I'm not convinced that anyone has shown that, so I remain open to the possibilities I described. Not convinced!!, but open.

see here I'm quoting because I'm answering to you, so this time you have a legitimate reason to take things personally and get confused.

 
ok my post:

I'm left with the computer processing and the formats. so I'm not testing for everything, only that.
I did 2 runs at different times with firefox and several tabs opened, so my typical way of listening to music on that laptop.
 
I fail to see a reason to suspect anybody would get an audible difference out of this. and I don't feel like I'm hearing one(with music, because listening to RRMA test file isn't a lot of fun^_^).  my anecdotal perspective is that if flac can sound different from calculation errors or codec mistakes, it didn't seem to do so on my computer while testing.
 
I haven't done the same thing in a loop involving a DAC and ADC

....  did it look like I'm making a general case of anything? trying to prove anything?
did this ask people to make a general case of anything?
can you misread my post any more than you just did?
 
 yes everything is possible and maybe somewhere a man can fly when meditating. I haven't seen one, and people I know also haven't. most of my understanding of gravity tells me it's not something that should happen. so if you come tell me that you've done it, I will want proof. I really don't get what is so unreasonable about it. should the not totally 0 possibility that such a man exists become a legitimate excuse for anybody to claim they can levitate without ever having to be accountable? nope.
so when we get audio claims of hearing atypical things, before going crazy about why it happens, and yes vs no, we want to make sure it happened. again I fail to see what's so traumatizing.  open minded, I try.
gullible, not if I can help it. that's where I draw the line.
I didn't say anywhere that it was impossible for flac to sound different on a device/player. you can look at my posts, I think this is my third one on this topic. I never tried to close any door, I just wish for people to stop putting the cart before the horse. and I must admit, more objective testing and less subjective claims wouldn't hurt in that section.
 
 
oh and no most didn't say "no, impossible". most people said it shouldn't happen, not the same thing. some asked to check if the diff was real, some said it wouldn't happen unless the player is broken, and other stuff. there is no need to turn skeptical people into absolute nay sayers when it's mostly not the content of their messages.
 
overall, not your best post.

 

[bilboda]

Intriguing update. Apparently there is a measurable difference between wav and flac. Seems like good science too.
http://www.enjoythemusic.com/magazine/viewpoint/0716/Why_Do_WAV_And_FLAC_Files_Sound_Different.htm

 

[VNandor]

  Intriguing update. Apparently there is a measurable difference between wav and flac. Seems like good science too.
http://www.enjoythemusic.com/magazine/viewpoint/0716/Why_Do_WAV_And_FLAC_Files_Sound_Different.htm

Any links to a place to buy audiophile-grade metadata for my FLAC collection?

 

[nick_charles]

  Intriguing update. Apparently there is a measurable difference between wav and flac. Seems like good science too.
http://www.enjoythemusic.com/magazine/viewpoint/0716/Why_Do_WAV_And_FLAC_Files_Sound_Different.htm

 
 
Actually it is pretty weak science. It is single blind which is normally considered a **terminal** error for any such tests and secondly there is no actual A/B comparison whatsoever just a sequence of signals so no requirement to be able to detect different/same. The proxy measurement is never validated.
 
If there is degradation or even change caused by a sequence of WAV<>/FLAC conversions there are much easier and more reliable/unbiased ways of detecting it. As a minimum the different wavs can be inverted and nulled against each other or the different frequency patterns can be measured, the overall amplitude and so on, clipping etc.... With the right kit you could even measure distortion.
 
If the conversions are causing audible alterations then the most likely candidate is a bug in software which is not the same as a format problem
 
As a laugh I will try the exercise myself with a CD rip and a sequence of conversions and post results presently...

 

[VNandor]

   
 
Actually it is pretty weak science. It is single blind which is normally considered a **terminal** error for any such tests and secondly there is no actual A/B comparison whatsoever just a sequence of signals so no requirement to be able to detect different/same. The proxy measurement is never validated.
 
If there is degradation or even change caused by a sequence of WAV<>/FLAC conversions there are much easier and more reliable/unbiased ways of detecting it. As a minimum the different wavs can be inverted and nulled against each other or the different frequency patterns can be measured, the overall amplitude and so on, clipping etc.... With the right kit you could even measure distortion.
 
If the conversions are causing audible alterations then the most likely candidate is a bug in software which is not the same as a format problem
 
As a laugh I will try the exercise myself with a CD rip and a sequence of conversions and post results presently...

"Whatever this property of the metadata might be, remarkably it is transferable from FLAC to WAV and back again to WAV, and with increasing negative effect with the number of conversions. Moreover, this particular file property cannot be detected as a change in file size or by conventional null testing procedures, yet it can be readily detected by ear and may be quantified by observed changes in vertical height reproduction." Taken from the article's second page. A rather interesting claim to make IMO. You can go ahead and try the null test but even the article admits that the differences can not be detected by "conventional null testing procedures".

 

[nick_charles]

   A rather interesting claim to make IMO....

 
And one which traditional DBT could easily verify or not - can you tell the difference between wav0 and wav5 reliably say 12/15 times - trivial and can be self-administered