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manisandher

Blue or red pill?

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38 minutes ago, manisandher said:

For anyone who's interested in doing some analysis of the digital (taken in real-time during the A/B/X) and analogue (taken immediately after A/B/X) captures, in the following link you'll find 4 files:

 

1. digital capture _ A

2. digital capture _ B

3. analogue capture _ A

4. analogue capture _ B

 

https://drive.google.com/open?id=10SD3SSdXV-P0ZFEte31NSFXeO0UhBYBi

 

Enjoy!

 

Mani.

Are there multiple analog captures for both A and B?  So that we can use a diff program to check whether A-B is significantly greater than A-A or B-B.

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Mani

 Unfortunately, when I tried to play the files, . CPlay which is my preferred player had no audio output .

(A job for tomorrow)  I used what I find the vastly inferior sounding "Jack of All Trades, Master of None"  (Foobar 2000) instead. (11.18PM)

The digital copies are markedly cleaner sounding with her voice, than the A/D conversion, (Analogue Capture) which appears to have some low level noise/grain with it . I will try the A/D again when I sort out the cPlay problem.

 

Regards

Alex

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7 minutes ago, sandyk said:

The digital copies are markedly cleaner sounding with her voice, than the A/D conversion, (Analogue Capture) which appears to have some low level noise/grain with it .

 

Yep, I agree Alex. I reckon I could get the digital and analogue captures a lot closer now, but think it's best to stick with the ones we captured on the day, when Mans was still here.

 

Mani.

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12 minutes ago, psjug said:

Are there multiple analog captures for both A and B?  So that we can use a diff program to check whether A-B is significantly greater than A-A or B-B.

 

Sure. In the link below, you'll find 3 of A and 3 of B. That's all we took on the day. Hopefully enough...

 

https://drive.google.com/open?id=1Eruo5N_NlKjnOkIJ-DMScK-1iXEaPP_y

 

Mani.

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I have failed miserably on the first set of analogue captures

 

foo_abx 2.0.2 report
foobar2000 v1.3.3
2018-04-16 14:37:58

File A: 3. analogue capture _ A.wav
SHA1: 9c7dbfe1ac5f00c6f3d3acd73c3d6a3fd1eaa59d
File B: 4. analogue capture _ B.wav
SHA1: 6c1ec457e27079d3e864c0396851e91185fcc982

Output:
DS : Primary Sound Driver
Crossfading: NO

14:37:58 : Test started.
14:38:19 : 00/01
14:40:37 : 01/02
14:40:59 : 01/03
14:41:08 : 01/04
14:41:41 : 02/05
14:41:51 : 02/06
14:42:19 : 03/07
14:42:30 : 03/08
14:42:46 : 03/09
14:43:20 : 03/10
14:43:20 : Test finished.

 ---------- 
Total: 3/10
Probability that you were guessing: 94.5%

 -- signature -- 
d4e41f058afbcceeabcc427c75d816d7ea834831

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53 minutes ago, psjug said:

Are there multiple analog captures for both A and B?  So that we can use a diff program to check whether A-B is significantly greater than A-A or B-B.

There 's not a whole lot in it but the spectral difference components look to be maybe slightly higher for A B (both 65k points)

 

track 3 (A) and 4(B)

difference%20between%203%20and%204.jpg?r

 

tracks 6 and 8 (both Bs)

 

difference%20between%206%20and%208.jpg?r

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26 minutes ago, adamdea said:

I have failed miserably on the first set of analogue captures...

 

I'm not really surprised. I wouldn't be confident in using these files in an A/B/X. But 3/10... :P

 

Mani.

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5 minutes ago, adamdea said:

There 's not a whole lot in it but the spectral difference components look to be about slightly higher for A B (both 65k points)

 

How confident are you that they're perfectly aligned?

 

Mani.

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24 minutes ago, manisandher said:

 

How confident are you that they're perfectly aligned?

 

Mani.

All I've done is take the tracks, invert one and combine. Perhaps Mansr can help, but I would have reckoned they null about as well (order of magnitude) as any two tracks ever do.

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50 minutes ago, adamdea said:

There 's not a whole lot in it but the spectral difference components look to be maybe slightly higher for A B (both 65k points)

 

track 3 (A) and 4(B)

difference%20between%203%20and%204.jpg?r

 

tracks 6 and 8 (both Bs)

 

difference%20between%206%20and%208.jpg?r

 

Make sure you remove the first 0.5 second or so from both captures. Mans indicated there were some differences at the beginning of the captures.

 

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11 minutes ago, pkane2001 said:

Make sure you remove the first 0.5 second or so from both captures. Mans indicated there were some differences at the beginning of the captures.

 

Yes, that should suffice. And DON'T try to align them because it will be too difficult (up to impossible). But te removal of that first 0.5 seconds seems mandatory.

 

But see ? the first problem already arises. Not thought of. Nothing wrong with the listening session itself, but with the recording of the very same there's a slight problem when used for listening to that.

What fun.

 

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16 minutes ago, pkane2001 said:

Make sure you remove the first 0.5 second or so from both captures.

 

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

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I'll happily leave someone else to do this, although i can't see anything special about the first 0.5s. [at a glance fft with and without it look the same] More important to miss off the last 2 seconds.

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Just now, adamdea said:

I'll happily leave someone else to do this, although i can't see anything special about the first 0.5s. [at a glance fft with and without it look the same] More important to miss off the last 2 seconds.

 

Here are two digital captures, overlaid, that include the entire length of both captures. Once I lopped off the beginning and the end, the captures show no differences at all:

 

A_B_FR.thumb.jpg.9d36e8271dbcc780fe001ef17eed7a66.jpg

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1 minute ago, pkane2001 said:

Once I lopped off the beginning and the end, the captures show no differences at all

 

Yep, lopping off the ends eliminates the Tascam's 'auto sync' function. Once done, all digital captures are identical.

 

Mani.

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2 minutes ago, pkane2001 said:

 

Here are two digital captures, overlaid, that include the entire length of both captures. Once I lopped off the beginning and the end, the captures show no differences at all:

 

A_B_FR.thumb.jpg.9d36e8271dbcc780fe001ef17eed7a66.jpg

Are you referring to the s/pdif captures? I am referring to the analogue outs. You will never get two analogue captures to null perfectly.

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Just now, adamdea said:

Are you referring to the s/pdif captures? I am referring to the analogue outs. You will never get two analogue captures to null perfectly.

 

As I said, "Here are two digital captures"

 

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5 minutes ago, pkane2001 said:

 

As I said, "Here are two digital captures"

 

More to the point you started this hare running 

 

"Make sure you remove the first 0.5 second or so from both captures. Mans indicated there were some differences at the beginning of the captures."

 

I have never been talking about the recording of the orginal bitstream but the analogue outs. [btw they are of course all digital captures.... but cf psjug's orginal post at the top of the page]

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2 minutes ago, adamdea said:

More to the point you started this hare running 

 

"Make sure you remove the first 0.5 second or so from both captures. Mans indicated there were some differences at the beginning of the captures."

 

I have never been talking about the recording of the orginal bitstream but the analogue outs. [btw they are of course all digital captures....]

 

Sorry if this wasn't clear. If digital SPDIF captures (as opposed to analog) show differences, then it's reasonable to assume that the same differences might exist in the analog captures. Hence my suggestion to lop off those parts.

 

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24 minutes ago, pkane2001 said:

If digital SPDIF captures (as opposed to analog) show differences, then it's reasonable to assume that the same differences might exist in the analog captures. Hence my suggestion to lop off those parts.

 

The Tascam's 'auto sync' function no doubt works differently for an S/PDIF vs. analogue input, both seeming to have their own peculiar issues.

 

Mans has said that some (not all) of the digital captures have something weird going on in the first 10k samples or so. So yes, it'll be necessary to lop off the first 50ms or so, and then the ends.

 

With an analogue input the 'auto sync' function is a law unto itself. It's set to begin at -54dB and seems to achieve this OK. But I've had situations where it's inverted the channels for the first 1/2 a second or so! In which case, lopping off only 50ms may not be enough.

 

Having said this, a very cursory look at the analogue captures suggests to me that the Tascam was actually behaving itself. So I doubt any lopping off at the beginning will be necessary.

 

Mani.

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12 minutes ago, manisandher said:

first 10k samples or so. So yes, it'll be necessary to lop off the first 50ms

 

That would not be consistent with 44100 samples per second (also not with 176400, although more close).

The 0.5 seconds would be better.

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36 minutes ago, adamdea said:

Are you referring to the s/pdif captures? I am referring to the analogue outs. You will never get two analogue captures to null perfectly.

My understanding is diffmaker has a method to deal with the alignment problem.  It can't be perfect but apparently this gives alignment that is not limited by the sample interval.  However, I've never used this software so I'm not sure I would be much good for doing this.

 

What is the high frequency stuff seen on the analog captures?  Is this pickup or something expected from the recorder?

 

 

 

 

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Just now, psjug said:

My understanding is diffmaker has a method to deal with the alignment problem.  It can't be perfect but apparently this gives alignment that is not limited by the sample interval.  However, I've never used this software so I'm not sure I would be much good for doing this.

 

What is the high frequency stuff seen on the analog captures?  Is this pickup or something expected from the recorder?

 

 

 

 

Mainly modulator noise I imagine.

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1 hour ago, adamdea said:

All I've done is take the tracks, invert one and combine. Perhaps Mansr can help, but I would have reckoned they null about as well (order of magnitude) as any two tracks ever do.

The problem with this is that no matter how carefully you align the tracks, they'll still be off by a fraction of a sample. This causes a spurious difference that increases with frequency.

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