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How to find the difference in two recordings taken from same source?

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UltraFine

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Can you attach some FLAC files instead of MP3. Just zip them up, keep them short, the 5 or 6 seconds should be enough. Do that and I can likely help.

You are right. It was not smart to attach mp3. Here are FLAC Files.


I have included 3 tracks for comparison. In comparison 1 and 2 I have prepared samples where you can clearly hear the difference.

U.
 
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UltraFine

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OP
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Hi Guys

One thing you might try is Audacity. I do not know if it would work, but the the video seems to suggest it will. Please note this is not about the device that he is testing but rather his use of Audacity to detect a difference between recordings. Obviously it is towards the end of the video. As Audacity is free itmight just do what you are trying to. The biggest thing seems to be getting the two recordings aligned, but I guess this is just practice.

Hope this helps Regards
Pegwill

I watched the video. It might be an interesting method. I think the spectrogram he creates with the tool "SoundExchange" would work well.
Not sure if this is the right url to the tool: https://sox.sourceforge.net/Main/HomePage
This tool has no GUI by the way.
 
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Not exactly. Look at the manual. The front connectors combine two ways of connector types, XLR (3kOhm) and 6.3mm jack (60kOhm) which goes into the center. The 2i2 applies a different gain and impedance whether you use XLR or the jack. You have to use a 6.3mm jack plugged into the front inputs. Secondly you adjust the gain so the green light just comes on once in a while when recording. In eg Ableton you can monitor also if the signal does not clip (stay ca 6dB below 0dB).

What does your preamp do? Is it a phono preamp? Or does the Technics has a phono preamp included?

(The 2i2 is a very capable (low noise -110dB and distortion -93dB) device - you just need to learn to use it correctly. I have the 4i4).
@HarmonicTHD , you opened my eyes to the 6.3 jack possiblity. I really did not know that. The Technics SL-1210MK2 has only one OUTPUT.
It is chinch cable. Here is a pic:
So I need a phono pre-amp. I also fully understand that clipping is an issue and know how to watch it. I think this is not the issue with my system. First step for me is to find a way how to make the difference that I hear visible.
 
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The phono preamp appears to have balanced line output transformers- likely 600R. How are you terminating them into the 2i2 interface? which connector? (TRS or XLR and which selection)

Your phono preamp:

au5729dtrxzn3lb67uae.jpg

EELA Audio 804 and Scarlett 2i2 both have XLR connectors. I use those. No 6.3inch cable.
 

Blumlein 88

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Having seen the larger file, A from elsewhere looks like it was dynamically compressed. Maybe from another mastering, maybe the CD if it was compressed more. Here it is after an attempt at level matching which can never be quite right due to the compression of one vs the other. That also will muck with any frequency response comparisons. Obviously the compressed one is brighter with more highs, but whether the vinyl rip is wrong is open to question. They do indeed sound different.

1674143822894.png
 
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UltraFine

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@Blumlein 88 , you speak my mind so much.
Yes it is true, the Comparison 1, Version A sounds compressed. You got a point.
But still, if you ask me, even with compression, there should not be imho such a weird difference in sound color.
If you look at Comparison2 from my upload here: https://we.tl/t-ADp4zD2osA.
The A-Version is a vinyl rip from some other guy. B is my vinyl rip. It might be a better selection for comparison. In that track you can also hear the coloration. (I also admit, the vinyl rip A could be compressed to, hehe).

Gruß
U.

Having seen the larger file, A from elsewhere looks like it was dynamically compressed. Maybe from another mastering, maybe the CD if it was compressed more. Here it is after an attempt at level matching which can never be quite right due to the compression of one vs the other. That also will muck with any frequency response comparisons. Obviously the compressed one is brighter with more highs, but whether the vinyl rip is wrong is open to question. They do indeed sound different.

 

lowgain

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Listening and looking at your samples, I would say there is something wrong with your preamp? Do you have to set the gain on the preamp?

Not a vinyl or preamp expert, but from what I can tell if I de-noise your own (B) recording and increase the gain it sounds much more like the A recording.
I posted both of the spectrograms (with sox as you mentioned above). You can tell that B is clearly more silent, but the noise is pretty much the same (I looked at that in more detail than in these screenshots).

So, since a preamp should help with getting a better signal-to-noise, I guess that's where I would start?
I have not much knowledge of hardware though, software person :)
 

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HarmonicTHD

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@HarmonicTHD , you opened my eyes to the 6.3 jack possiblity. I really did not know that. The Technics SL-1210MK2 has only one OUTPUT.
It is chinch cable. Here is a pic:
So I need a phono pre-amp. I also fully understand that clipping is an issue and know how to watch it. I think this is not the issue with my system. First step for me is to find a way how to make the difference that I hear visible.
Look at the post of restorerjohn - you have a phono amp (yes it might be old). The phono preamp is needed not only to boost the signal from the cartridge but to account for the RIAA equalization or whatever you call that. (sorry I am not a vinyl guy).

So as before, connect the vinyl player to the phono amp and now get a cable, one for each channel, from the phono amp XLR outputs to the 2i2 6.3mm TRS line inputs (60kOhm impedance) (look on Amazon for a cheap prebuilt cable XLR to TRS).

In the Focusrite control panel you can check the signal routing (so the inputs correspond to the correct channel L R) and I believe it should say line input ! Don’t switch on the 48V mic phantom power by accident ! . I can check tomorrow about the Focusrite panel routing.

Slowly turn up the gain as described before until the green light just comes on during the loudest passages. Now as the gain can be adjusted independently for each channel you need to make sure they are set equally. Let’s eyeball it for starters.

If the problem still persists then we have a look at the phono preamp.

@restorer-john could you x check and did I miss anything?
 
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Blumlein 88

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@Blumlein 88 , you speak my mind so much.
Yes it is true, the Comparison 1, Version A sounds compressed. You got a point.
But still, if you ask me, even with compression, there should not be imho such a weird difference in sound color.
If you look at Comparison2 from my upload here: https://we.tl/t-ADp4zD2osA.
The A-Version is a vinyl rip from some other guy. B is my vinyl rip. It might be a better selection for comparison. In that track you can also hear the coloration. (I also admit, the vinyl rip A could be compressed to, hehe).

Gruß
U.
This other one also looks like the rip from elsewhere is dynamically compressed. Even if there is no other difference they'll sound different. The other one may also have had compression done more at higher frequencies than lower. Such tools are readily available. We could try and compress your rip to get them closer together. The issue is you are comparing apples and oranges by this point. You could compress your rip if you like it, or you could EQ it if you think it is dull. Compression generally makes a recording sound lively anyway. Even if there is nothing wrong with your preamp the compressed one will sound brighter, more present and less rolled off.

1674182483126.png
 

Holmz

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It might be hard to sync up two different vinyl recordings.

^lol yeah - just a bit^
(Very job nice on the subtlety.)

Assuming one can do a correction to align them at the front, the speed will mean that they need some resampling all along the way to get them onto a standard time and phase.
It is not trivial in practice, but it’s relatively trivial in theory.
 
OP
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@HarmonicTHD ,

I am not quite sure, I understand fully why a XLR-to-6.3inch cable could solve the problem.
Right now I connect XLR-to-XLR to Scarlet2i2. Scarlet2i2 itself notices that the input arrives from XLR and not 6.3inch and uses the correct impedence which fits the XLR input.
Even if it does not, the only problem that would occur is a too low signal, right? What I observe though is a coloration or lets say a disbalance in frequency response. Even before I used Scarlet2i2, as I used the SoundCard of my PC I had this coloration. (I can upload rips recorded with the SoundCard). Even then I could hear the coloration. Thus the coloration does not come from Scarlett and replacing the cables would not solve the problem, would it?

You assume that it is prolly my pre-Amp that might be producing the effect. You might be right. Though I ask myself if also some old electronics (capasitors) in the vinyl player could produce this effect, or maybe the catridge/needle?

Cheers
Ultra

Look at the post of restorerjohn - you have a phono amp (yes it might be old). The phono preamp is needed not only to boost the signal from the cartridge but to account for the RIAA equalization or whatever you call that. (sorry I am not a vinyl guy).

So as before, connect the vinyl player to the phono amp and now get a cable, one for each channel, from the phono amp XLR outputs to the 2i2 6.3mm TRS line inputs (60kOhm impedance) (look on Amazon for a cheap prebuilt cable XLR to TRS).

In the Focusrite control panel you can check the signal routing (so the inputs correspond to the correct channel L R) and I believe it should say line input ! Don’t switch on the 48V mic phantom power by accident ! . I can check tomorrow about the Focusrite panel routing.

Slowly turn up the gain as described before until the green light just comes on during the loudest passages. Now as the gain can be adjusted independently for each channel you need to make sure they are set equally. Let’s eyeball it for starters.

If the problem still persists then we have a look at the phono preamp.

@restorer-john could you x check and did I miss anything?
 

HarmonicTHD

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@HarmonicTHD ,

I am not quite sure, I understand fully why a XLR-to-6.3inch cable could solve the problem.
Right now I connect XLR-to-XLR to Scarlet2i2. Scarlet2i2 itself notices that the input arrives from XLR and not 6.3inch and uses the correct impedence which fits the XLR input.
Even if it does not, the only problem that would occur is a too low signal, right? What I observe though is a coloration or lets say a disbalance in frequency response. Even before I used Scarlet2i2, as I used the SoundCard of my PC I had this coloration. (I can upload rips recorded with the SoundCard). Even then I could hear the coloration. Thus the coloration does not come from Scarlett and replacing the cables would not solve the problem, would it?

You assume that it is prolly my pre-Amp that might be producing the effect. You might be right. Though I ask myself if also some old electronics (capasitors) in the vinyl player could produce this effect, or maybe the catridge/needle?

Cheers
Ultra
The reason (hypotheses) and @restorer-john is here more an expert than me is, that if you connect a 600R impedance out phono preamp to a low (3kohm) input via the XLR, it can lead to a drop in level for certain frequencies which is exactly what you describe as dull sound. However if you connect via TRS to the 60kOhm line input, the preamp does not have to supply as much current and frequency changes are less likely. John needs to critique my explanation as I am not an EE.

Hope that helps your understanding.
 
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Pegwill

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Hi Guys

I see that some are using Audacity, there is a facility to compare one recording to another and it will show the difference s, this may be useful. The details are here in this thread (page 1) in my previous post.

Hope this helps

Have a good weekend

Regards
Pegwill
 

Digby

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I'm confused about the purpose of your post.

You are comparing your recordings (of vinyl) made to digital recordings (yes, they will sound different) and vinyl transcriptions done on other equipment (yes, they will sound different too). Does the vinyl sound dull before it is recorded to digital, if so the problem is cart/pre-amp/interface, if it only sounds dull after conversion it is probably the fault of the interface.

FWIW I briefly tried a Scarlett interface but found the sound quality wasn't acceptable. I upgraded to RME and have had no qualms since.

I do sometimes wonder if my digital recordings lose a bit of 'air' compared to direct playback. However, the difference is so small, I doubt I would notice in a blind setting, which suggests it may just be my imagination.
 

Blumlein 88

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Do you need the 8th generation loopbacks to convince?
 
OP
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I watched the video that you attached. It is great. The guy in the video still alligns the tracks by hand though.

Hi Guys

I see that some are using Audacity, there is a facility to compare one recording to another and it will show the difference s, this may be useful. The details are here in this thread (page 1) in my previous post.

Hope this helps

Have a good weekend

Regards
Pegwill
 
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