I didn't see a thread about this free program though it has popped up in discussions about eliminating crowd noise.
I had a few significant hiccups recording 9 bands in one night on two stages simultaneously and this program has saved my bacon on a few of these.
Quick impressions after using it a couple of times -
1) It's not a silver bullet solution for crowd noise but it does help
2) it works for decreasing but not eliminating chatter over instrumental music
3) it's resource intense - neither of my computers that I use for music have a recognized Nvidia GPU which can cut processing time way down. Without a compatible Nvidia GPU you must rely on CPU processing which is pretty slow - depending on how you utilize it and how big your files are
Hurdle #1 - I was given a monitor feed and stage access for mics at a gig with 4 bands playing back to back. I wasn't able to monitor well set up right next to the stage left stacks so I didn't realize until afterwards that my feed sounded good except for a serious lack of MAIN VOCAL. I was disappointed to say the least. So I tried running the monitor mix tracks through UV5 song by song and then mixing the isolated vocal track back into the initial mix of the monitor feed and my stage lip mics. It works remarkably well. It's not perfect but it's certainly better than it was.
Hurdle #2 - at the same time I was recording in another room that had 5 bands overlapping slightly with the bands on the main stage. It's a little room maybe 25x40 ft and it gets packed. I ended up running my AKG C522 stereo mic > Oade DR100 rig in the back of the room since that was the only way I could get to it without a fight and also keep it from getting walked on. So the tight packed crowd was loud AF with the chatter especially during the Robert Walter, Reed Mathis, Simon Lott, Will Bernard set that I was the most excited about. I ran the 30 second sample mode on the file and I was very impressed with the improvement. Not perfect but for sure a big difference. If you listen to the isolated vocal track (which is the noise I'm trying to remove here - instrumental band) you can hear a little of the Hammond organ but not a lot.
There's a lot of options and and big community of users of this open source free tool. I will probably use this frequently going forward.