10 Pro, unmix "issue"

[Magnus_N]

Hi Robin,

First of all, thank you for SL 10! I have just updated from 9, and must say that this is a vastly improved app. I use it almost exclusively inside Cubase 12 Pro (latest) for unmixing stems. The new addition to unmix drums is very useful, and the unmix process for drum kit (the “old” one, where you can separate out the whole kit from the rest of the music of a song) is vastly improved.

I also like that the sliders are gone, and have been replaced with Fast or Best options instead. But mainly, thanks for the improved algorithm. I record my band live during our rehearsals, and from this I make material from our albums. As we record everything live, improvising, the unmix feature has allowed me to isolate vocals completely from mic spill. And now, it seems I can get usable results when isolating the overhead drum mics, and the spot mics on the bass and snare drums. This is GREAT! With these isolated tracks I can work more creatively with our material.

I noticed one thin, however. When dropping the unmixed track into Cubase from SL 10, the unmixed track is inserted 1 sample late. I noticed this by accident when zooming in to check something and manually had to move the track into sample accurate position.

Is this a bug or by design? I guess it is not intended to be like this. My projects are at 44.1 kHz sample rate, btw.

Again, thanks a huge lot, Robin, for this version of SL. So far, it seems to bring me more of what I specifically need from it. And with better results. That is grand!

Now I will have to start thinking about a gpu to help my pc with the processing…

Best,

Magnus

[Robin_Lobel]

@Magnus_N Glad you enjoy it !

Thanks for reporting the one sample shift, I’ll look into this for patch 2.

[Robin_Lobel]

@Magnus_N I couldn’t repro the one sample shift, what exact version of Cubase do you use ? And what would be the typical step by step to repro and see that shift ?

[Magnus_N]

Hi Robin,

Thanks for looking into this so quickly. I use Cubase Pro 12.0.70 (i.e. the latest version), on Win 10.

I have used the unmixing algo in SLP 10 four times now I think, always from inside CP12. The only time I haven’t noticed the sample shifting (between 1 and 3 samples, but always shifted forward) was when I unmixed a whole Cubase audio part, occupying the full project length (please ask, if it is not clear what I mean). As far as I could see, the result here was sample accurate.

Mostly, I unmix only sections of an audio event, for instance: in a seven minute long project (song), I may unmix only the 2 minutes in the middle of the song track that contain vocals. It is in these cases that the sample shifting occurs.

My Cubase projects always consist of 10-12 recorded audio tracks (44.1 kHz/24 bit) of my band playing live in our rehearsal space. We always improvise, so this is how we make our music.

So, from inside Cubase, this is my process in these cases:

1 I isolate the part to be unmixed by cutting where it starts and where it ends…
2. I duplicate the track that I want to unmix. The duplicated tracks contain identical cuts.
3. I open the SLP10 extension for the part that I want to unmix on the original (not the duplicate) track, and apply the unmixing at Best quality.
4. On the duplicate track, I delete the part corresponding to the unmixed part.
5. I drag the unmixed part from SLP10 - for instance Vocals - into the gap left by the deleted part on the duplicate track.

If I zoom in all the way now on the start of the unmixed part in Cubase there will be a gap of from 1-3 samples. Correspondingly, if I zoom in on the end of the unmixed part in Cubase, there will be an overlap of roughly the same size.

I then continue by

6. Removing the SLP10 extension from the part on the original (non-duplicate) track. (I do this to keep the size of the cpr file to a minimum.)
7. Usually, I now delete the original track from the project.

Please let me know if you need any further details. I can also provide you with screenshots if it would be useful for you.

All the best, and thanks again for a great great update!

Magnus

[Robin_Lobel]

@Magnus_N Thanks for the step by step but yes, as I wasn’t able to repro please provide screenshots:
-of where you did the cuts, and the layout of tracks/tracks duplicates that you mention
-and a zoomed view of the shift you see, both start and end

[Magnus_N]

Hi Robin,

Please find attached a number of screenshots. Their titles should explain their respective contents.

Please ask any questions.

All the best and again, thanks for looking into this,

Magnus

[Magnus_N]

And here is the end of two tracks that were unmixed in their entirety. As you can see the unmixed parts extend beyond the ends of their originals (the processed tracks).

Magnus