AI spectral separation - is this still only remastering?

MusicBrainz Style
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HI there. I recently stumbled upon the Paranoid release (Black Sabbath) by Prof Stoned. the release was already listed in the MB database but the original author created new recordings for all tracks. since remasters should share the same recording I pushed edits accordingly. there is some discussion about it now.

https://musicbrainz.org/edit/104375561

here is the thing though: Prof Stoned is a sound engineer who used DeMix for his work process. DeMix uses AI spectral separation to extract individual instrument and vocal lines from one track. he then worked on these tracks individually and mixed them back together. the song structure is still exactly the same.

should these tracks still share the same recording?

MBs definition of recordings state

I would argue though that we usually don’t have any insight in the audio work flow of a specific release. and solely based on the tracks themselves they share the same exact song structure. so at least there are clearly not remixes by MBs definition.

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if the tracks were seperated and re-mixed (meaning the volume levels on instruments would likely be different and whatnot), that would be a mixing difference and not a mastering difference, meaning it would get new recordings

I don’t know whether I’d mark it as a different mix or a remix, but if it’s credited one way, I’d go with that

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I’m not an audio engineer but isn’t it possible to apply EQ to specific frequency ranges and not the full spectrum? or in other words - is it not possible to apply mastering to a mix which results in different volume levels for different parts of the music depending on the acoustic characteristics of the instruments?

“For Those About To Rock” by AC/DC comes to my mind. There is the Albert CD release (CDP 7466652) and one by Atlantic (SD 11111-2). Both share the same recordings in the DB but the former one has vocals that are clearly more quiet than the guitars compared to the later one.

back to Paranoid. here is comparison screenshot of the waveforms.

warpigs
warpigs1660Ă—708 56.7 KB

the upper one is from the Intercord CD (INT 830.108, 1986), which Prof Stoned lists as one of his two audio sources (the other one being one of the original vinyl releases). the lower one is his editing work.

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I’ve always seen Prof Stoned stuff as the same recording, just heavily remastered. He still has same source recording. No one has gone back and re-recorded anything.

You’ll see some of my edits of his releases on the Pink Floyd side (and a few others). It is also the AcoustIDs that lead me to also focus on “same recording”.

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thanks for the input. using AcoustID as a criteria seems to be the right call.

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AcoustID wasn’t made for identifying recordings though, not to mention the many other problems it has

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… but they are very useful for this purpose. Remasters often submit to the same acoustID while remixes usually don’t. They will be distinguishable by their fingerprints.

EDIT: A̶n̶d̶ ̶f̶o̶r̶ ̶t̶h̶e̶ ̶w̶a̶v̶e̶f̶o̶r̶m̶s̶ ̶(̶a̶l̶s̶o̶ ̶v̶e̶r̶y̶ ̶u̶s̶e̶f̶u̶l̶)̶ ̶-̶ ̶f̶r̶o̶m̶ ̶w̶h̶a̶t̶ ̶i̶s̶ ̶v̶i̶s̶i̶b̶l̶e̶,̶ ̶i̶t̶ ̶l̶o̶o̶k̶s̶ ̶l̶i̶k̶e̶ ̶a̶ ̶r̶e̶m̶a̶s̶t̶e̶r̶.̶
though not entirely … listening is also very useful :slight_smile:

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It is useful part of a toolbox. The descriptions of how these releases are made are also a key part of deciding. Sometimes he does edit and change the recordings making something new. He is really good with his detailed write-ups.

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Prof. Stoned explicitly labels this release as a remix - it’s called “Paranoia: Remixed”. Why not take this at face value?

Looking through their website, it seems Prof. Stoned has for the longest time created remasters. The “[album]: Remixed” series seems to be a relatively new thing in their efforts, the apparently first release being from 2021. In the release information for “Paranoia: Remixed”, Prof. Stoned even warns purists that they might want to stick to original releases of this album. Even with newer remasters such as Genesis’ “From Genesis to Revelation”, Prof. Stoned mentions use of a “DeMix Remaster treatment” for several tracks, “allowing for a much needed improvement of the mixing!” ( Prof Stoned: Rare & Deleted: Genesis - From Genesis to Revelation {Mono} (1969) [A Prof Stoned Comp] ) This indicates to me that Prof. Stoned is aware that some of their modifications go beyond mere remastering and into remixing (i.e. creating an alternate mix that modifies how instruments relate to each other in the mix even though the song structure remains identical).

The mentioned rebalancing of individual instruments and the addition of ambience to drums, guitar and vocals very much appear to me as mix-level changes. These changes to me result in the creation of alternate mixes of “Paranoia” tracks - essentially remixes if there’s currently no better term for it.

Perhaps MusicBrainz needs a way to better distinguish between what many think to be remixes (some artist taking the stems of an original piece and changing it around to their liking, modifying the structure, adding new elements, leaving out elements of the original) and what could be termed “alternate mix” (e.g. the 2007 editions of the main catalogue Genesis albums mixed anew by Nick Davis which faithfully recreate the original pieces’ structure from the multitrack recordings but with completely new mixes). At least for “Foxtrot” and “A Trick of the Tail” (the two Genesis albums I’ve looked up on MB in the course of thinking about this issue), the 2007 editions’ tracks point to different recordings than the releases based on the original mixes in all their different mastering variations (LP masters, original CD masters, Definitive Edition remasters, etc. - releases based on the respective original mix).

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I would do so. (but I would expect, it shows up comparing the fingerprints too)

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Part of the problem is language. MusicBrainz has its own definitions of “Recording”, “Remix” and “Remaster”.

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what IvanDobsky said was also one of the issues for me here. before pushing the edits to merge the recordings I looked up how MB defines remixes and remasters. and MBs definition of a remix is in my own words a new song composition which isn’t the case with this release here.

A substantially altered version of a song, produced by mixing together individual tracks or segments of one or more source works. The artist doing the remixing can be the original artist. The source audio material can be from any part of the process; including the final mix, master, remaster, or original raw audio materials. If the tracks have been significantly modified, more than is necessary to produce a continuous mix, then the action described by relationships is considered to be remixing, not compilation or DJ mixing. Note: not everything called “remix” is really a remix in the classic sense.

I came to the conclusion that using DeMix in this context is still just some form of enhanced remastering using modern developments in audio technology.

apart from this, my thought process was this - if our decision to merge or use separate recordings depends on the information the sound engineer of this release gives us, then I would question the robustness of the definitions we use.

would there be any confusion or discussion about this if it weren’t for the case that the album is called “Remix” and that the engineer told us what he is doing? I’m very convinced that without these information everyone would categorize this release as a remaster.

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I think I have to reconsider my previous position on this matter.

I recently added all the Beatles bootleg albums by Prof. Stoned. to elaborate: Prof. Stoned applied his demix magic (using AI spectral separation to extract the individual audio lines from a mixed track) on the first 6 studio albums from the Beatles. especially for the early albums as far as I know there were only mono mixes and oldschool stereo mixes available (with hard separation of the vocals and instruments to one or the other channel).

in the Musicbrainz entries for the albums I linked the tracks to the recordings he used as a source according to his infos. but recently I found out that the official 2022 rerelease of “Revolver” also used a AI demix process as well as the upcoming rereleases of the Blue and Red album. for the 2022 Revolver release new recordings were added to the database.

revisiting the MB definition of a recording it states

Generally, the audio represented by a recording corresponds to the audio at a stage in the production process before any final mastering but after any editing or mixing.
https://musicbrainz.org/doc/Recording

I guess we will see more new demix mixes in the future. I don’t feel comfortable anymore with my previous position to simply categorize this as a remaster. especially when the number of audio channel changes or in this case distribution of vocals and instruments to the channels changes fundamentally.

visiting the style guideline for recordings it states

A group of audio tracks used in a recording can be mixed and possibly edited in a different way. For example, the volume or tone of individual tracks may be altered, or effects may be applied to them. The result is often labelled on a track list as a remix, mix, dub, overdub or version, and should always be given a new recording in MusicBrainz.

and

It may be the case that very similar released tracks have different numbers of audio channels. The most common audio channel configuration is stereo (two channels; left and right). However, there are several common audio channel configurations used in recordings, including mono (one channel), quadraphonic (four channels) and surround sound (various multi-channel configurations).

These different configurations should generally be distinguished by using separate recordings. However, the original multi-channel recording should be used when multiple channels have been combined into a single channel without actually creating a new mix from the source audio tracks. A similar exception should be made where a mono channel has been split into two stereo channels - for example, in Duophonic recordings.

https://musicbrainz.org/doc/Style/Recording

and if one should add new recordings for these demix tracks, which relationship should one use to link them to the source recordings and demix artist?

https://musicbrainz.org/relationships/recording-recording

the “edit” relationship seems to be the only that fits? I saw that the Revolver 2022 tracks uses the “remix” relationship, which would be an argument to use it here as well. but MBs definition of remix doesn’t really apply here or does it?

https://musicbrainz.org/relationships/artist-recording

here I would use the mix and mastering engineer relation to link it to Prof. Stoned.

looking forward to your thoughts on this.

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Back in the pre-AI days, engineer Robert Parker developed a technique for stereo separating mono recordings, resulting in a series of “Jazz Classics in Digital Stereo” releases. I haven’t found a better rel than “edit of” for these either (see here for example).

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“edit of” perfectly fits, IMO. :slight_smile:

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the “edit” relationship seems to be the only that fits? I saw that the Revolver 2022 tracks uses the “remix” relationship, which would be an argument to use it here as well. but MBs definition of remix doesn’t really apply here or does it?

I don’t think mix alterations such as Demix use should be marked with edit relationships. The mentions of edits in MB’s documentation (e.g. Style / Recording # Edits) indicate structural changes, i.e. cuts beyond simply fading at the beginning or end of a recording; censoring words; and cutting out or duplicating passages to shorten or extend a track. No mention of changes to the mix there (so a track could both be an edit and a remix, depending on what work has been done to alter it from its original version).

I’d continue to suggest labeling Demix use “remixes”, but MB’s documentation unfortunately isn’t consistent on what constitutes a remix. There are different (partial) definitions of a “remix” depending on where you look.

Hidden for brevity: three places in MB docs that contain conflicting information about what constitutes a remix.

Terminology:

A substantially altered version of a song, produced by mixing together individual tracks or segments of one or more source works. The artist doing the remixing can be the original artist. The source audio material can be from any part of the process; including the final mix, master, remaster, or original raw audio materials. If the tracks have been significantly modified, more than is necessary to produce a continuous mix, then the action described by relationships is considered to be remixing, not compilation or DJ mixing. Note: not everything called “remix” is really a remix in the classic sense.

  • In urban music styles, hip hop especially, it’s typical to call “remix” to a new version of a song with different guest rappers; these should probably not be linked to any artist as “remixer”.
  • In video game music, “remix” is often used to describe new arrangements and covers of existing music; these are not remixes in the above sense and involved artists are probably not “remixers”.

I read this part of the documentation as almost a carte blanche: any somewhat perceivable (this is my take on the “substantially altered”) change to a recording (e.g. volume or tonal changes) constitute a remix, regardless of what material that new version uses, adds or omits, as long as it uses at least some part of an original recording.

Style / Recording:

A group of audio tracks used in a recording can be mixed and possibly edited in a different way. For example, the volume or tone of individual tracks may be altered, or effects may be applied to them. The result is often labelled on a track list as a remix, mix, dub, overdub or version, and should always be given a new recording in MusicBrainz.

This part of the documentation implies that simple volume changes (e.g. decreasing the volume of an instrument) constitutes a remix. (The mention of “edited” in that definition seems a little misleading: it’s an unnecessary convolution of “mix”/“remix” and “edit”.)

Relationship Type / Remixer:

This links a recording to the person who remixed it by taking one or more other tracks, substantially altering them and mixing them together with other material. Note that this includes the artist who created a mash-up or used samples as well.

The definition of this relationship type implies that a remix is created by adding other material on top of altering an original recording (or its stems). That requirement seems to conflict with other places where MB tries to define a remix, especially the two instances I quoted above.

I’m sure those are only three of many more mentions and (at least partial) definitions of “remix” in MB’s documentation.

I’d continue to go for remix relationships, as demixing a recording into new stems and then mixing them back into a new mixdown does fit at least two of the remix definitions I could find in the docs, and it certainly seems to be creation of a new mix and thus a new recording. However, the fact that the documentation for remix relationships explicitly requires addition of new material complicates this a bit. :frowning:

Perhaps it’s useful to split the topic “remix inconsistently defined” from this thread and then look at how we can gain a consistent and accepted understanding of what a remix is.

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yeah, I noticed this as well. which probably led to my initial confusion about the matter. I’ve gone through the MB terminology again and wasn’t satisfied with using the “edit” relationship either.

I think for linking the demix record to the source record it is best to use the “remix” relationship as you suggested. for the artist relationship however I’d use the “mix engineer” instead of the “remixer” one.

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I created new recordings for all the demix albums by Prof. Stoned and added disambiguation for them. I would go on and copy relations from the original recordings (using the available userscript) that Prof. Stoned used for the demix process. but I’m wondering if some of them only make sense in the context of the original recording. could somebody have a look?