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Blue or red pill?


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1 hour ago, testikoff said:

Here you go:

 

- Delta closeup (frequency range 20...20000Hz; logarithmic scale):

AC12_d_log.jpg

I had done something similar and have the same result.  Testikoff had already posted by the time I made it back here. 

 

I was using 8k FFT so each bin is about 21 hz.  Up until 11 khz the difference is +/- .01 db per bin and mostly less than that.  It gets up to .05 db a few places above 15 khz and does a little worse the higher you go then.  So spectrally, the balance is the same. 

 

Now this isn't sample for sample close to identical for those wondering.  If you invert and null it you only get about a 15 db null.  

 

@manisandher, not that you haven't been generous with us, but could you put up the 10 khz analog captures?

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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3 minutes ago, esldude said:

... could you put up the 10 khz analog captures?

 

Sure. I'd like to redo them with the 'clean' 10kHz test tone Mans sent me. Will do this tomorrow.

 

Mani.

Main: SOtM sMS-200 -> Okto dac8PRO -> 6x Neurochrome 286 mono amps -> Tune Audio Anima horns + 2x Rotel RB-1590 amps -> 4 subs

Home Office: SOtM sMS-200 -> MOTU UltraLite-mk5 -> 6x Neurochrome 286 mono amps -> Impulse H2 speakers

Vinyl: Technics SP10 / London (Decca) Reference -> Trafomatic Luna -> RME ADI-2 Pro

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6 hours ago, PeterSt said:

 

I think it is really @manisandher (or @mansr) who should do this. Not everybody and everybody in different fashion. :o

 

toomanycooksproverb.jpg

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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For what its worth, without sample rate drift correction Audio Diffmaker shows a null depth of 37.3 db left and 37.5 right.  With sample rate drift correction (when it doesn't blow up) it shows a null depth of 94.5 db left and 92.3 db right.  

 

I complain about Diffmaker quite a lot.  When it works and shows deep null depth it isn't wrong in my experience.  More often it blows up or shows something ridiculous like a null depth of less than 10 db when its obvious by other means the null is deeper than that. 

 

So curious and interesting results.  I am not sure what could be left with nulls into the 90s with a 16 bit DAC with a noise in that same vicinity.  

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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47 minutes ago, esldude said:

For what its worth, without sample rate drift correction Audio Diffmaker shows a null depth of 37.3 db left and 37.5 right.  With sample rate drift correction (when it doesn't blow up) it shows a null depth of 94.5 db left and 92.3 db right.  

 

I complain about Diffmaker quite a lot.  When it works and shows deep null depth it isn't wrong in my experience.  More often it blows up or shows something ridiculous like a null depth of less than 10 db when its obvious by other means the null is deeper than that. 

 

So curious and interesting results.  I am not sure what could be left with nulls into the 90s with a 16 bit DAC with a noise in that same vicinity.  

 

So here's what I tried (similar to what was proposed earlier): align the A and B analog captures in Audacity, using sample # display.

 

Invert one B track, combine A and B. Plot the spectrum of the resulting track. There's definitely noise as the result, but also a few frequencies. Here's the resulting spectrum plot:

 

 

spectrum.thumb.jpeg.bdeb17d6a39a70e82f0240ceb57f592b.jpeg

 

Here are the original tracks (top one is A, middle is B inverted, and bottom is the combined two):

 

diff.thumb.jpeg.b733bb52ca05eaa4d280b99917249421.jpeg

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Just downloaded the files, and my first thought is that this piece of music is as far from what I would use to evaluate a rig as one could get ... "You wish to testdrive the Ferrarri, sir? ... OK, a few rules: never go over 2,000 RPM; never go beyond 2nd gear; only on the smooth road in front of the showroom; there's a glass to water inside that will tip over and let us know if inertial forces are too great ... enjoy the run, sir!!" ...

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3 minutes ago, psjug said:

Audio DiffMaker is able to get better alignment than doing it the way you did.  See Section 5.2 in their paper:

http://www.libinst.com/AES Audio Differencing Paper.pdf

 

I’m sure it can, but I didn’t have it or know how to use it.  I did see perfect matching between peaks and valleys in a bunch of  areas where I spot checked it. I zoomed in so that individual samples were visible.

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1 hour ago, esldude said:

For what its worth, without sample rate drift correction Audio Diffmaker shows a null depth of 37.3 db left and 37.5 right.  With sample rate drift correction (when it doesn't blow up) it shows a null depth of 94.5 db left and 92.3 db right.  

 

I complain about Diffmaker quite a lot.  When it works and shows deep null depth it isn't wrong in my experience.  More often it blows up or shows something ridiculous like a null depth of less than 10 db when its obvious by other means the null is deeper than that. 

 

So curious and interesting results.  I am not sure what could be left with nulls into the 90s with a 16 bit DAC with a noise in that same vicinity.  

Did you listen to the difference file?  Could you make out anything like the music track or do you only hear noise?

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4 minutes ago, psjug said:

Did you listen to the difference file?  Could you make out anything like the music track or do you only hear noise?

You don't actually hear anything at a normal to slightly high volume. 

 

I put 75 db of digital amplification to the difference file and it sounds like interstation hiss on a mistuned FM tuner. No indication at all of anything resembling voice or music or any of that.  I thought of making that available, but a file of basically nothing except inaudible hiss isn't too interesting.   

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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14 minutes ago, fas42 said:

Just downloaded the files, and my first thought is that this piece of music is as far from what I would use to evaluate a rig as one could get ... "You wish to testdrive the Ferrarri, sir? ... OK, a few rules: never go over 2,000 RPM; never go beyond 2nd gear; only on the smooth road in front of the showroom; there's a glass to water inside that will tip over and let us know if inertial forces are too great ... enjoy the run, sir!!" ...

 

 This track is at quite a low level, and will highlight any masking low level noise which DOES affect how individual female voices can sound.

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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11 minutes ago, sandyk said:

 

 This track is at quite a low level, and will highlight any masking low level noise which DOES affect how individual female voices can sound.

 

I work in a different fashion - I don't care whether her voice is different, I want it to to be convincing ... I have a recording of Odette, the Harry Belafonte one, from the '60s, which fits the bill of being extremely low level - the system either makes her voice a caricature of that style of singing; or, a living, breathing person.

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1) kudos to @mansr and @manisandher because you see how much work this second stage of making accurate measurements and good technical analysis is. Many pitfalls. Real work ;)

 

2) consider applying something like a Henning function to the start and end of the generated pure tone file. the abrupt start and stop of a file will generate harmonics.

Custom room treatments for headphone users.

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52 minutes ago, fas42 said:

 

I work in a different fashion - I don't care whether her voice is different, I want it to to be convincing ... I have a recording of Odette, the Harry Belafonte one, from the '60s, which fits the bill of being extremely low level - the system either makes her voice a caricature of that style of singing; or, a living, breathing person.

 

 This is NOT what this thread is about. It's about hearing differences between files with identical check sums, so it does matter  whether her voice sounds a little different or not, in one of the samples.

Music from the 60s is NOT suitable for these types of comparisons due to recording limitations of that period, and the quality of the surviving masters.

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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16 minutes ago, esldude said:

Actually it is about hearing differences between the same file played with different settings in the playback software. 

 

You can pussy foot around the wording all you like, but these ARE from the same music file, created using different settings in Software. (whether software or hardware created is really immaterial) 

The claim from Mani, and verified by his  9 out 10 correct choices ,  is about them having audible differences, despite having identical Binary Content. 

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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20 minutes ago, STC said:

 

If I were to control the volume level in my JRiver, will the Tascam recorder capture different bits for the changes in the volume? 

Seems to me it would have to yes.  You'll be sending out different levels of the file digitally, and that means different bits digitally sent to either the recorder or a playback DAC. 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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For what it's is worth, I tried some foobar ABX on the two analog captures. 

 

16 trials each session.  A break between each session.

 

7/16

11/16

8/16

 

So individually or 26/48 for the aggregate is still pretty much guessing. Was using my Sony MDR7510 Pro headphones and Focusrite Forte. 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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5 minutes ago, esldude said:

Seems to me it would have to yes.  You'll be sending out different levels of the file digitally, and that means different bits digitally sent to either the recorder or a playback DAC. 

 

I thought the volume information would be discarded. If I were to play at 75% volume in Audacity and export a 16/44.1 as 24/192 format and another one played at 100% volume in Audacity and exported as 24/192 format, can these two be bit identical? The same must be happening when the bit-identical data streams reach the Altmann DAC. It must be carrying some analogue signal that were captured or ignored in all digital domain of the Tascam recorder.

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4 minutes ago, STC said:

 

I thought the volume information would be discarded. If I were to play at 75% volume in Audacity and export a 16/44.1 as 24/192 format and another one played at 100% volume in Audacity and exported as 24/192 format, can these two be bit identical? The same must be happening when the bit-identical data streams reach the Altmann DAC. It must be carrying some analogue signal that were captured or ignored in all digital domain of the Tascam recorder.

I don't think I understand what you have in mind.  

 

In the Audacity example, yes the files you are sourcing from are bit identical, however if you use the digital volume in Audacity the string of bits sent to the DAC will be different with different volume settings.  Now if you save that file when done playing the file itself has not been changed. 

 

I don't remember if Mani used volume control in software or not.  If so, as long as he set it and didn't change it, the string of bits during playback will be identical.  In your Audacity example if you play the file twice with 75% on volume the bits sent to the DAC will be the same in each instance even though these aren't the same bits as the source file. 

 

Am I looking at this right or have I misunderstood you?

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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29 minutes ago, esldude said:

I don't think I understand what you have in mind.  

 

In the Audacity example, yes the files you are sourcing from are bit identical, however if you use the digital volume in Audacity the string of bits sent to the DAC will be different with different volume settings.  Now if you save that file when done playing the file itself has not been changed. 

 

I don't remember if Mani used volume control in software or not.  If so, as long as he set it and didn't change it, the string of bits during playback will be identical.  In your Audacity example if you play the file twice with 75% on volume the bits sent to the DAC will be the same in each instance even though these aren't the same bits as the source file. 

 

Am I looking at this right or have I misunderstood you?

 

image.thumb.png.e972e59f06db43493318f7d207b17fa7.png

 

I took Mani's digital A and exported it as 16 bit WAV. In one the replay volume was set at maximum and in another the volume was set at 0.7. See the red circle.

 

According to the file size both are identical but I am not sure if the checksums are identical. I guess they must be. 

 

When I listen at 0.7 and 1 replay volume but sounded different. That's expected. However, the export of the files under both circumstance appears to be bit-identical. There must be a way to verify this.

 

Going back to OP, whatever difference appears after DAC must be carrying something that was ignored in the digital domain. Is it the gain voltage? or something that the SFS changing that affect the analogue side of the stream but doesn't alter the digital stream.

 

I hope I made it clear. 

 

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3 minutes ago, STC said:

 

image.thumb.png.e972e59f06db43493318f7d207b17fa7.png

 

I took Mani's digital A and exported it as 16 bit WAV. In one the replay volume was set at maximum and in another the volume was set at 0.7. See the red circle.

 

According to the file size both are identical but I am not sure if the checksums are identical. I guess they must be. 

 

When I listen at 0.7 and 1 replay volume but sounded different. That's expected. However, the export of the files under both circumstance appears to be bit-identical. There must be a way to verify this.

 

Going back to OP, whatever difference appears after DAC must be carrying something that was ignored in the digital domain. Is it the gain voltage? or something that the SFS changing that affect the analogue side of the stream but doesn't alter the digital stream.

 

I hope I made it clear. 

 

In Audacity you've have not changed the file when you adjust that volume slider.  So exporting the file with that slider at 1.00 or .75 changes nothing about the file.  If you were to play the file from Audacity out to the Altmann DAC, then the two settings result in different volumes and different bits.  Not because there is any volume information in the file.  Audacity will just reduce the sample values as needed as it plays back the file.  Nor does this change the file held in Audacity.  

 

Easy way to check is open original and saved file together.  Use the invert function under Effects on one of the files.   If they are the same you get nothing. If you combine the files using "mix and render" under Tracks you'll get a flat straight line if they are bit identical.  

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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1 minute ago, esldude said:

If you were to play the file from Audacity out to the Altmann DAC, then the two settings result in different volumes and different bits.

 

Actually, this was a confusion for me for a long time.

 

I used to control the volume with a preamplifier after the Mytek DAC.  I have an option to bypass the volume control in the DAC completely and also in the JRiver. However, I remember under one of the combination the volume control had no effect. That was too long ago and I do not use a preamp now so I can't double check on that.

 

Anyway, thank you for clarifying that the changes in volume will alter the bits.

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7 hours ago, esldude said:

With sample rate drift correction (when it doesn't blow up) it shows a null depth of 94.5 db left and 92.3 db right.

 

That seems to corroborate Testikoff's analysis.

 

7 hours ago, esldude said:

I am not sure what could be left with nulls into the 90s with a 16 bit DAC with a noise in that same vicinity.  

 

5 hours ago, esldude said:

I put 75 db of digital amplification to the difference file and it sounds like interstation hiss on a mistuned FM tuner. No indication at all of anything resembling voice or music or any of that.

 

Thanks for doing all this.

 

Mani.

Main: SOtM sMS-200 -> Okto dac8PRO -> 6x Neurochrome 286 mono amps -> Tune Audio Anima horns + 2x Rotel RB-1590 amps -> 4 subs

Home Office: SOtM sMS-200 -> MOTU UltraLite-mk5 -> 6x Neurochrome 286 mono amps -> Impulse H2 speakers

Vinyl: Technics SP10 / London (Decca) Reference -> Trafomatic Luna -> RME ADI-2 Pro

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