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Thread: Spectrogram Help

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    Default Spectrogram Help

    Hi, I'm a bit new to audio editing and I'm trying to learn a bit while on lockdown. I'm just after a bit of help with a spectrogram view of some audio:

    Screenshot 2020-06-06 at 11.18.53.jpg

    This is the same source but from 2 different CDR rips. Is anybody able to tell me what the differences mean please? I was assuming they would be the same, but clearly they aren't!

    Any help would be appreciated!

    Cheers

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    If those are from the same CD but ripped using two different programs, then one of them (the one below) is clearly altering the sound during the ripping process.
    Check the settings and codecs to see if both software are using the same methods of extracting the track. At first glance it looks like the one on top is a more faithful and pure rip, while the one at the bottom suffered some sort of compression/manipulation.

    If those two are of the same recording, but from different CDs released at different times or by different labels, then the same applies: one of them seems to have been manipulated (EQ, denoise, etc.) during production and the other not.
    Last edited by ruben77; 2020-06-06 at 01:57 PM.
    R.M.

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    Quote Originally Posted by ruben77 View Post
    If those are from the same CD but ripped using two different programs, then one of them (the one below) is clearly altering the sound during the ripping process.
    Check the settings and codecs to see if both software are using the same methods of extracting the track. At first glance it looks like the one on top is a more faithful and pure rip, while the one at the bottom suffered some sort of compression/manipulation.

    If those two are of the same recording, but from different CDs released at different times or by different labels, then the same applies: one of them seems to have been manipulated (EQ, denoise, etc.) during production and the other not.
    Thanks. They are 2 different CDs of the same source and I was thinking that the bottom one had been messed with in some way. Is it possible it is lossy?

    Annoying thing is that the bottom one is more complete than the top, but it's riddled with pops and ticks on the full rip.

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    i guess he meant two different CD-R copies, originated from the same source.

    if so, the lower spectrum clearly shows some kind of lossy encoding and, also, it misses that tracking signal which is visible on the upper spectrum (that horizontal line at treble).

    then, some more investigation about those 2 CD-R copies (if they are 2 CD-R copies, as i guess) might be needed, to try to really understand the true origin of the both of them.

    Cheers,

    Vince.

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    Quote Originally Posted by vince666 View Post
    i guess he meant two different CD-R copies, originated from the same source.

    if so, the lower spectrum clearly shows some kind of lossy encoding and, also, it misses that tracking signal which is visible on the upper spectrum (that horizontal line at treble).

    then, some more investigation about those 2 CD-R copies (if they are 2 CD-R copies, as i guess) might be needed, to try to really understand the true origin of the both of them.

    Cheers,

    Vince.
    Thanks Vince, that's correct, they are CD-Rs. I suspected the bottom might be lossy and I wondered what that horizontal line was on the top one. Thanks for clearing it up for me.

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    you're welcome,

    i see you had just confirmed that they are two different CD-R copies just while i was posting my previous reply.

    those tracking signals can be there for a few reasons... depending on the actual frequency they are.
    so, they might be tracking signals which go on the recording from oldschool CRT video screens placed close to the audio gear (frequencies in the 15 to 17 Khz range, don't remember the exact numbers by memory) or ,i.e., the tracking/pilot signal of FM stereo broadcasts (at 19Khz and which usually the mpx filters should remove but this doesn't always happen)... and possibly a few other kinds...
    So, in regards of the actual frequency of the tracking signal, we can understand some more about the actual lineage of a recording.

    Cheers,

    Vince.

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    Quote Originally Posted by vince666 View Post
    you're welcome,

    i see you had just confirmed that they are two different CD-R copies just while i was posting my previous reply.

    those tracking signals can be there for a few reasons... depending on the actual frequency they are.
    so, they might be tracking signals which go on the recording from oldschool CRT video screens placed close to the audio gear (frequencies in the 15 to 17 Khz range, don't remember the exact numbers by memory) or ,i.e., the tracking/pilot signal of FM stereo broadcasts (at 19Khz and which usually the mpx filters should remove but this doesn't always happen)... and possibly a few other kinds...
    So, in regards of the actual frequency of the tracking signal, we can understand some more about the actual lineage of a recording.

    Cheers,

    Vince.
    Hmm, that's interesting. It was recorded in 1994 at a small venue in London and I'm guessing it was onto cassette. Other than that I have no info. Can the tracking signal occur during transfer?

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    Quote Originally Posted by Small Fish View Post
    Can the tracking signal occur during transfer?
    yes, of course it can occur during copying process or also during transfer process.

    actually, unless the "master" is recorded with the recorder very close to some CRT screen (or the first tape copy is recorded from FM broadcast it it's from the radio), the tracking signals usually are added during the following generations.

    sometimes, i also find tracking signals on (official) vinyl LPs at very high frequencies like in the 30 to 33Khz range but i don't know which is their actual origin or if they are related to my turntable system (but i doubt it because i found them only on some LP rips of mine).

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    Quote Originally Posted by vince666 View Post
    yes, of course it can occur during copying process or also during transfer process.

    actually, unless the "master" is recorded with the recorder very close to some CRT screen (or the first tape copy is recorded from FM broadcast it it's from the radio), the tracking signals usually are added during the following generations.

    sometimes, i also find tracking signals on (official) vinyl LPs at very high frequencies like in the 30 to 33Khz range but i don't know which is their actual origin or if they are related to my turntable system (but i doubt it because i found them only on some LP rips of mine).
    Thanks for your help Vince

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    you're welcome.

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