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Blue or red pill?


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18 minutes ago, pkane2001 said:

There's still a difference in frequencies above 17KHz, like I saw with other A/B analog captures earlier:

 

That's interesting. I suspect it has something to do with the MOTU's noise-shaping, noise being shifting to above 17kHz or so. We'd expect the noise to be randomly different for A and B.

 

Easy way to find out. Do you get the same sorts of differences above 17kHz when comparing As with As, and Bs with Bs? It'd probably be best to stick with the later analogue captures taken with the MOTU rather the earlier ones with the Tascam. I think the best ones to compare would be:

 

- 11, 15 and 23 for A

- 12, 16 and 24 for B

 

All of these were taken at 0dB attenuation level, and through the MOTU's fixed (more direct) inputs.

 

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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2 hours ago, manisandher said:

 

That's interesting. I suspect it has something to do with the MOTU's noise-shaping, noise being shifting to above 17kHz or so. We'd expect the noise to be randomly different for A and B.

 

Easy way to find out. Do you get the same sorts of differences above 17kHz when comparing As with As, and Bs with Bs? It'd probably be best to stick with the later analogue captures taken with the MOTU rather the earlier ones with the Tascam. I think the best ones to compare would be:

 

- 11, 15 and 23 for A

- 12, 16 and 24 for B

 

All of these were taken at 0dB attenuation level, and through the MOTU's fixed (more direct) inputs.

 

Mani.

 

Mani, somehow I missed the download link for 11 and 12, and now can't find it in this thread. Could you please post it again?

 

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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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On 5/4/2018 at 11:05 AM, manisandher said:

 

That's interesting. I suspect it has something to do with the MOTU's noise-shaping, noise being shifting to above 17kHz or so. We'd expect the noise to be randomly different for A and B.

 

Easy way to find out. Do you get the same sorts of differences above 17kHz when comparing As with As, and Bs with Bs? It'd probably be best to stick with the later analogue captures taken with the MOTU rather the earlier ones with the Tascam. I think the best ones to compare would be:

 

- 11, 15 and 23 for A

- 12, 16 and 24 for B

 

All of these were taken at 0dB attenuation level, and through the MOTU's fixed (more direct) inputs.

 

Mani.

Hi Mani,

 

I think you might be right! Here's the comparison of 11 and 15 (both A captures). There's definitely a difference at the higher frequencies:

image.thumb.png.080abf721192f0d354b8e62d21a30893.png

 

Here's the divergent part, zoomed-in:

image.thumb.png.372daf09eaa38e69e3ec346818c599cc.png

 

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8 hours ago, pkane2001 said:

@manisandher, @mansr, did you gentlemen ever post the digital + analog 10KHz signal captures? I'd like to see what my software tool can dig up in those, if anything.

 

Will do...

 

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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10 hours ago, pkane2001 said:

@manisandher, @mansr, did you gentlemen ever post the digital + analog 10KHz signal captures? I'd like to see what my software tool can dig up in those, if anything.

 

 

Here you go @pkane2001:

 

Altmann Attraction DAC -> Tascam ADC

- original analogue & digital 10k sine tone captures

- same files used for 10k sine analysis that Mans posted earlier in thread

- taken during Mans's visit

-18dB attenuation applied during playback to match attenuation used during ABX with music track

 

https://drive.google.com/open?id=1BkaNqKhNV3HAZY7OYO2OCp4TpAK9LwKb

 

iFi Nano DAC -> MOTU ADC

- additional analogue & digital 10k sine tone captures

- analogue & digital captures taken simultaneously (but unfortunately at different rates)

- taken post Mans's visit (~ 3 weeks ago)

- 0dB attenuation applied

- audio PC -> USB -> iFi DAC -> analogue outputs -> MOTU ADC (analogue captures)

- audio PC -> USB -> iFi DAC -> spdif output -> Tascam spdif input (digital captures)

 

https://drive.google.com/open?id=1txIUyXVSbuiPtJm01fgiQVMGqHEi5TDA

 

If anything interesting comes of these, I'm happy to set things up again and redo whatever might be useful.

 

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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2 hours ago, manisandher said:

 

 

Here you go @pkane2001:

 

Altmann Attraction DAC -> Tascam ADC

- original analogue & digital 10k sine tone captures

- same files used for 10k sine analysis that Mans posted earlier in thread

- taken during Mans's visit

-18dB attenuation applied during playback to match attenuation used during ABX with music track

 

https://drive.google.com/open?id=1BkaNqKhNV3HAZY7OYO2OCp4TpAK9LwKb

 

iFi Nano DAC -> MOTU ADC

- additional analogue & digital 10k sine tone captures

- analogue & digital captures taken simultaneously (but unfortunately at different rates)

- taken post Mans's visit (~ 3 weeks ago)

- 0dB attenuation applied

- audio PC -> USB -> iFi DAC -> analogue outputs -> MOTU ADC (analogue captures)

- audio PC -> USB -> iFi DAC -> spdif output -> Tascam spdif input (digital captures)

 

https://drive.google.com/open?id=1txIUyXVSbuiPtJm01fgiQVMGqHEi5TDA

 

If anything interesting comes of these, I'm happy to set things up again and redo whatever might be useful.

 

Mani

 

Wow, thank you, Mani! All good fodder for my software testing. It's getting better. It's nice to have the visuals (plots) to go with the waveform alignment, as it gives me immediate feedback on how well it works and if anything needs adjusting.

 

I have to admit that your test results are puzzling me, as I can find no obvious repeatable differences between A and B analog plots. In some cases, analog A and B captures are a better match for each other than some other A and A captures! But, as I said earlier in this thread, this is what I find fascinating: an unexpected and unexplained result. So I'll keep digging ;)

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  • 3 weeks later...

@pkane2001 Impressive work so far!

Are we still thinking about analysing the imaginary part of the fourier transform and could a cepstrum analysis help to uncover (or dismiss) possible differences of the A vs. the B captures? 

[ Foobar2000 (with Resampler-V & SACD-Decoder) on mobile Skylake ]  —>  [ Stereo192-DSD ]  —>  [ 851A ] —> [ 805S or HD560S ]

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@Tsarnik, since you suggested cepstrum... How does one interpret it? What does a peak mean? Here's one analysis, for example (this is complex cepstrum, so also includes phase):

 

image.thumb.png.d32a00e67b17afac39d2c8b724a29f5f.png

 

It has a curious peak at 48KHz, so I assume this means the original recording was sampled at that frequency (?) even though the playback was at 192KHz. Both A and B captures have it, so it's not the smoking gun :)

 

If I zoom in to the left of that peak, I also see some smaller differences between A and B captures:

 

image.thumb.png.3fa2c3784f43232e46c5d9460f883d4b.png

 

But I don't know if these are significant, or what they represent. Any ideas? Interestingly, the spectrogram does show some energy around 48KHz, at least some of the time:

 

image.thumb.png.070f59b58cd64c54ff60315c18acfb09.png

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@pkane2001, I think I need to mention first that, unfortunately, I do not have any degree in signal theory (or anything that would come close to it). So my hope was that the trained members of our CA community would happily jump on the cepstrum bandwagon and elaborate. ?

As I understand it, the cepstrum, the "spectrum of the spectrum" can be used to analyse echos.

If the different SFS settings e.g. had caused any repetitive pattern of small-scale signals, cepstrum analysis might be able to unearth the "rahmonic" peaks at the fundamental period (unit=time) with which they might occur (provided they occur rather regularly).

That was my layman's reasoning (and speculation).

Small-scale signals like the ones measured by PeterSt and posted earlier in this thread (see image below).

 

If I am not mistaken (but I could well be) the peak at 48 kHz is a measure of the existence of the images that the non-brickwall upsampling filter generates, appearing after each 48 kHz, "overtones" to the fundamental at 48 kHz, so to say.

 

But I am by no means an expert on this and would like to refer you to the following links:

https://www.researchgate.net/publication/3321562_From_Frequency_to_Quefrency_A_History_of_the_Cepstrum

http://www.libinst.com/cepst.htm

https://www.researchgate.net/publication/276465999_Cepstral_Analysis_for_the_Application_of_Echo-Based_Audio_Watermark_Detection

 

 

PeterSt's XXHighEnd Analysis from Mar-28.png

[ Foobar2000 (with Resampler-V & SACD-Decoder) on mobile Skylake ]  —>  [ Stereo192-DSD ]  —>  [ 851A ] —> [ 805S or HD560S ]

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9 hours ago, Tsarnik said:

@pkane2001, I think I need to mention first that, unfortunately, I do not have any degree in signal theory (or anything that would come close to it). So my hope was that the trained members of our CA community would happily jump on the cepstrum bandwagon and elaborate. ?

As I understand it, the cepstrum, the "spectrum of the spectrum" can be used to analyse echos.

If the different SFS settings e.g. had caused any repetitive pattern of small-scale signals, cepstrum analysis might be able to unearth the "rahmonic" peaks at the fundamental period (unit=time) with which they might occur (provided they occur rather regularly).

That was my layman's reasoning (and speculation).

Small-scale signals like the ones measured by PeterSt and posted earlier in this thread (see image below).

 

If I am not mistaken (but I could well be) the peak at 48 kHz is a measure of the existence of the images that the non-brickwall upsampling filter generates, appearing after each 48 kHz, "overtones" to the fundamental at 48 kHz, so to say.

 

But I am by no means an expert on this and would like to refer you to the following links:

https://www.researchgate.net/publication/3321562_From_Frequency_to_Quefrency_A_History_of_the_Cepstrum

http://www.libinst.com/cepst.htm

https://www.researchgate.net/publication/276465999_Cepstral_Analysis_for_the_Application_of_Echo-Based_Audio_Watermark_Detection

 

 

PeterSt's XXHighEnd Analysis from Mar-28.png

 

I think your reasoning is mostly correct. I've read all the links you included, as well as a bit more on the use of cepstrum, including some books. Seems to me it is intended to find a pattern within a pattern. A standard FFT finds frequencies inside a sampled waveform, while cepstrum finds periodic patterns within these frequencies. For example, harmonics of some main frequency would produce a peak in the cepstrum at that frequency. As you say, cepstrum detects echoes, and harmonics are nothing but an echo of the fundamental frequency. It appears that it is used a lot in speech recognition tasks, which makes sense as it reduces the sampled waveform to a few key values (peaks) that represent the basis of a sound.

 

Cepstrum is certainly an interesting tool, but requires more testing and experimentation to see if it's telling us something about the differences between the music A and B captures produced in this thread :)

 

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  • 1 year later...

From the 'USB cables?' thread:

 

8 hours ago, sandyk said:

Then why don't you put your money where your mouth is, and resume the series of tests with Manishander, also including in those tests a comparison of his Lush USB cable with another USB certified cable of his choosing under DBT conditions !!!

 

7 hours ago, mansr said:

For starters, he doesn't want to. Furthermore, I'd prefer for any future testing to take place in a less chaotic environment. Lastly, the test Mani and I did had nothing to do with cables.

 

We conducted the blind test in a typical listening environment - my home. I don't live in a lab. People don't listen to music in a lab.

 

I was in my listening room, and you controlled the test from my office, with two closed doors and a hallway between us. Chaotic? What was chaotic about this environment?

 

And if it was a more 'chaotic' environment than you would have liked, it's even more impressive that I scored 9/10 in the ABX :P.

 

7 hours ago, mansr said:

For starters, he doesn't want to.

 

Can anyone blame me?

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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From the 'USB cables ?' thread:

 

9 hours ago, mansr said:

For the record, Mani was nothing but friendly when we met. It was only after I refused to bow down and lick his boots in response to whatever fluke gave rise to the infamous 9/10 that he turned nasty. Guess I should have seen it coming.

 

You really can't stand being proved wrong, can you?

 

Sad.

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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17 minutes ago, manisandher said:

From the 'USB cables ?' thread:

 

 

You really can't stand being proved wrong, can you?

 

Sad.

Guys

 Can we please drop this now ?

 It's not a good look coming from 2 well respected members.

As Peter said several times previously, you are highly unlikely to find any differences in the Digital Domain. He has certainly tried hard enough .

 In fact, with a couple of my comparison files where others agreed there were obvious differences in SQ,  al,fe sent them to his parent Asian company for analysis.

 They sent back to him a detailed 50 page report, but were unable to find any differences.

Ideally, we need to use analogue capture techniques at the Analogue output of the DAC.

If the differences can be heard, then they can be measured given suitable equipment, provided we know what to look for. 

 The levels of the differences may well turn out to be much lower than previously thought possible ?

Kind Regards

Alex

 

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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1 hour ago, sandyk said:

As Peter said several times previously, you are highly unlikely to find any differences in the Digital Domain. He has certainly tried hard enough .

 

Alex, that there are no differences in the digital domain has been accepted by all parties in this thread.

 

1 hour ago, sandyk said:

Ideally, we need to use analogue capture techniques at the Analogue output of the DAC.

 

We did exactly that. The last 1000 or so posts of this thread have all been about differences in the analogue captures.

 

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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Quote

We did exactly that. The last 1000 or so posts of this thread have all been about differences in the analogue captures.

 

IIRC,  the differences weren't definitive enough to convince Mansr, or we wouldn't still be having this discussion about the validity of the 9 out of 10 results .

 

 

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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32 minutes ago, sandyk said:

IIRC,  the differences weren't definitive enough to convince Mansr, or we wouldn't still be having this discussion about the validity of the 9 out of 10 results .

 

I thought Paul's last analysis of the two analogue captures (done a while ago now) was very convincing that there were indeed measurable differences between the analogue captures:

 

On 5/30/2018 at 7:00 PM, pkane2001 said:

My comparison tool, DeltaWave, is coming along well. A bunch of new features and enhancements were added recently, as well as some badly needed optimizations to speed it up.

 

Here's the latest analysis of a couple of files uploaded by Mani from the Red & Blue pill thread.  Enjoy the comparison, and please make suggestions on what else can be added or improved.

 

Comparison of analog audio captures 15A and 16B

 

1. First, the raw waveforms (removing 3 seconds from front and back of each file):

image.thumb.png.a5fe3b4f0b1363e3fce523ef10ea7195.png

 

1a. The same, zoomed-in:

image.thumb.png.6d4d372db0d8d91a0e7c3ae760d8cb47.png

 

 

2. Here are the matched waveforms, after DeltaWave performed all the phase and gain matching:

image.thumb.png.fac95e47f69091ab05cafcfca023038e.png

 

The same, zoomed in to show how accurate the alignment was:

image.thumb.png.c7af99256916be0c85008ba48a5c111d.png

 

3. Now, the two spectrum charts comparing A and B after matching:

image.thumb.png.f6cc12848e576c48ae18cdb6590dba01.png

 

4. Waveform of the delta between A and B after matching:

image.thumb.png.768947e193e61fcc20ed57b0e92776e0.png

 

4a. Zooming in on the difference around 10 seconds mark:

image.thumb.png.a0334566b988f4f422bb77684e0b040b.png

 

5. Spectrogram of 15A:

image.thumb.png.aa4c4873b3fb712b978e433cf1cd5127.png

 

6. Spectrogram of 16B:

image.thumb.png.c9d82c5b10696087b667890aded2d8a1.png

 

7. Spectrogram of the delta (difference of A and B):

image.thumb.png.c735b2a7f97ba727c49e457a702c7ec9.png

 

8. And finally, a complex cepstrum analysis of A and B, showing some periodicity in the frequency domain (where the peaks are):
image.thumb.png.ab708f54db09771449c436abe435d199.png

 

9. Oh, and forgot one more. Not sure how useful this is, consider it work in progress. A direct phase comparison of A and B derived from the frequency domain FFT analysis:

image.thumb.png.c9cfc1f038aa67084e8c4c25102c314a.png

 

If people still aren't convinced by my 9/10 ABX result and these measurements, I doubt anything will shift their entrenched beliefs.

 

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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Mani

 Please refresh me. Were the captures done using a further A/D conversion ?

Doing that would make it much harder to find the subtle differences that we are hearing.

 While 9 out of 10 should be worthy of further investigation , even the 6 sessions with 8 repeats in each that were done originally with my files were not accepted as proof by the sceptics .

Alex

 

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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8 minutes ago, sandyk said:

Please refresh me. Were the captures done using a further A/D conversion ?

 

Yep. Absolutely no other way of getting captures [digital files that can be analysed] of the DAC's analogue output.

 

8 minutes ago, sandyk said:

Doing that would make it much harder to find the subtle differences that we are hearing.

 

Well this was the reservation that Peter and I had right from the outset. But I felt it was worth a try nevertheless.

 

8 minutes ago, sandyk said:

While 9 out of 10 should be worthy of further investigation...

 

The 9/10 result of the blind ABX supports the hypothesis that I could hear differences between bit-identical playback to a 99% probability. The doubters seem to want to ignore this fact.

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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4 minutes ago, manisandher said:

Yep. Absolutely no other way of getting captures [digital files that can be analysed] of the DAC's analogue output.

 

An Analogue tape deck perhaps ? Not so easy to analyse the results though, but could be the basis of DBT sessions.

 

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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3 hours ago, sandyk said:

As Peter said several times previously, you are highly unlikely to find any differences in the Digital Domain. He has certainly tried hard enough .

 

I have never said anything of the kind. Never.

Can you now, please, finally stop mixing up your ideas about audible differences in the exact same files, with differences I (and Mani for that sake) incur for by different playback means ?

Maybe write it on a wall somewhere so you won't forget ?

 

Kind regards,

Peter

Lush^3-e      Lush^2      Blaxius^2.5      Ethernet^3     HDMI^2     XLR^2

XXHighEnd (developer)

Phasure NOS1 24/768 Async USB DAC (manufacturer)

Phasure Mach III Audio PC with Linear PSU (manufacturer)

Orelino & Orelo MKII Speakers (designer/supplier)

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