Issue link: https://digital.copcomm.com/i/1529890
40 W I N T E R 2 0 2 5 I C A S Q U A R T E R L Y guitars, keys, and horns. This had some of the worst aliasing on all tracks. The vocals were very shrill. Somehow, the bass had weird overtones added (possibly from the guitars and horns?). I was surprised that RX performed so poorly. Personally, I do not consider the stems to be usable. RipX DAW (Hit'n'Mix) I had not heard of RipX DAW, it just started showing up after I did a few searches for other programs. It is essentially a music tool for DJ's that includes stem separation. The bass sounded good, with some occasional peculiar distortion. The vocals had far too much aliasing and were much too bright. One way to check for aliasing is to listen to the cymbals, and in this case, it was immediately evident. There was also a lot of guitar bleed on the horns track. These tracks were essentially unusable. Ultimate Vocal Remover (UVR) The Ultimate Vocal Remover can't be beat for the price. It's free and open source! This means there is no manual or support, and you have to spend a lot of time futzing around with it to find the best algorithm for what you are doing. That's great if you have patience or can take a lot of time to learn the program, but for quick changes, I did not find it as useful. It can split into four stems. The stem splits were pretty good, but still had aliasing. Moises.AI Moises, like Lalal, does its processing online. It is subscription- based. This had significantly less aliasing than the other programs. In addition to splitting up to six tracks, it also creates a metronome track, as well as deducing the keys and chord structures of the piece, all the way down to giving tablature for guitarists, including "Capo Mode"—very cool! Tracks can be exported as WAV files in the web app only unless you buy a Pro subscription. This had the best bass extraction by far, with complete attack and decay. There was still audible aliasing on cymbals and some on the vocals. The brass attacks were not great, and there were some horns on the lead guitar track. However, I would rate Moises as the most useful for extracting individual parts. I did find that to make most stems usable, I had to add at least a little reverb to correct for the envelopes being cut off (and it can sometimes mask some of the aliasing if you are lucky). This, of course, makes the mix sound different, although you may end up adding reverb for a film mix anyway. I also did some experiments trying to take the best version of each track from all the apps and see if they could blend together. As I expected, it introduced more problems, however, I think you could choose one program for most of the tracks and maybe sneak in a split from another program (again using lots of reverb). Conclusion While my assessments may be a little harsh, I completely understand that we are still at the beginning of what separation tools will someday be able to accomplish. And while none of these are near the level of Peter Jackson's "MAL" (Machine Audio Learning) separation software that was used on recent Beatles projects, I believe they will get significantly better, probably sooner than most of us would expect. Acon, Lalal, and UVR all have affordable entry-level versions. RX Music Rebalance is included in RX Standard. RipX DAW has an entry-level option (and educational discount). Personally, before investing a lot of money in any of these programs, I will wait a while to see what happens or buy them as needed.