iZotope RX 8 Music Rebalance

Having seen a lot of DIY track separations getting posted in the Stems/Multis section I decided to get a copy of the software and try it out. The algorithms in Music Rebalance extract audio from a track and split them into Vocal, Percussion, Bass and Other output stems.

From what I've experienced the app is good at extracting DIY Acapellas and has a good go at isolating drum tracks in Percussion, but it all goes pear shaped when it tries to extract what it considers to be the Bass track, which invariably ends up as a muddy, almost sub bass track. The residual, Other instruments track is far better.

I tested the app out by feeding in just a bass guitar track from a studio stem set and the algorithms split the source into a muddy bass frequency track and the majority of the information ended up in the Other track.

Whilst RX 8 seems very handy for producing usable acapellas, where artifacts can get lost in the mix it seems pretty hopeless for producing usable stem sets to give separations of backing tracks.

I wonder if other people are having better results with it and might have some tips to share on how to get a Bass track from the algorithm that is listenable on its own?

RX uses Spleeter, so expect pretty much the same quality.

Bass is tricky because it can be live, sub, synth, hard, etc.

The best tool for extracting this particular stem is Demucs. It's not muddy and does an excellent job, but also adds very slight noise to all of the stems it outputs, so that might be off-putting.

Thanks very much for that recommendation I'll have to see if I can give Demucs a try. I was hoping to find something that could isolate bass guitar parts well enough to make it easier to transcribe them.

I'm still getting used to RX 8 and would be grateful if someone who is expert at using it could advise on some problems that I've encountered.

I'm using RX 8 in standalone mode on a Win 10 machine. If I try to use Music Rebalance in Batch Processor mode then I hit problems. Within the Batch Processor dialogue box I can adjust the faders for the 4 filtered stems but there is no option (at least none that I can see) to enable you to select Render to generate a single stereo output file, or Separate to generate 4x filtered stems from each input file. The default appears to be Render. If I set batch mode to run with a single input file as a test then it will render the output file as above, However, if I add several input files to create a batch then RX 8 appears to try to process them all simultaneously and crashes closing its window down. I'm not having much luck in finding any info about using RXB in Batch Processor mode but haven't found anything flagged up to say that it isn't possible to do this.

If someone else has encountered this problem, or would be prepared to give it a quick test on their system, then I'd be grateful to know if they got this combination of features to work and how.

Just in case anybody picks up on this RX 8 thead in future, I've now been in touch with iZotope's technical support and they recommend not trying to use music rebalancer in batch processor mode. It seems to be an oversight in the design and it won't work with multiple files.