<< Conversion to a Performance Track for an mp3 version of the utility track will only work on one track. That leaves all the other utility tracks to continue accumulating the large wave files. That is the price of trying to make BIAB into a DAW. >>

I'm not following your line of thought. Any Track regardless if it's a normal Legacy Track or Utility Track can be converted to a Performance Track. But that's the simplest form of a Performance Track. With the introduction of Audio recording with BIAB 2015 for both PC and Mac, the inclusion of the "move audio to Performance Track" feature, BIAB became an "easy to use multi-tracking program". A DAW is software in which the DAW’s user interface replicates the same features of a multi-track tape recorder such as play, record, and other controls such as track controls, a mixer, faders, buses vu-meters and so on. So, BIAB is a DAW because DAW's replicate Multi-Track recorders which BIAB is.

My point is not to debate the definitions of BIAB, DAW and Multitrack recorders but to help you and nearly every other user of BIAB understand that with your purchase of BIAB in every version be it PC or Mac since 2015, the purchase price included a multitrack/DAW program...

See the video: Band-in-a-Box for Mac: Recording Audio

Every feature other than the visibility factor of Utility Tracks introduced with the BIAB 2021 Utility Track feature has been possible since 2015! In prior years, what's now Utility Tracks were just audio files saved to a folder. That of course means that these "Utility Tracks" were not limited to only 16 Mixer Tracks. A user could save as many audio files limited only by available storage space.

I believe that most of the issues still being ironed out with the new Utility Tracks is because they are physical audio file tracks rather than virtual tracks like the original BIAB Mixer Tracks are. Since 2015, the Audio Channel in the BIAB Mixer has been the only physical Track in the Mixer. Each of the other channels, Bass, Piano, Drums, Guitar, Strings, Melody and Soloist contained data and not audio. The audio produced is similar in concept to sound heard from a synthesizer playing MIDI data. Legacy Tracks hold instructions, not audio unless that track is altered by the Performance Track process. A RealTrack is the audio clip stored in a folder, not the data on a MIDI or RealTrack BIAB Mixer Channel. The Performance Track feature allows for each of the other 7 virtual channels to be converted to a format the BIAB Mixer recognizes to allow them to accept a physical audio file.

Because BIAB is a multitrack recorder and player, multitrack principles, techniques and processes apply to the program. Since 2015, BIAB has been capable of producing high quality mixes comprised of dozens of instruments onto dozens of tracks far exceeding the 8 physical tracks visible on the main screen interface.

Because of the multitrack capability of BIAB, the program offers some very powerful, complex arrangement and automatic features that most users are unaware of and mostly go unused. Applying multitrack techniques result in BIAB creating smooth transitions between Soloists and other instruments changing between sections, cross-fades, Fade-in's, fade-outs, eliminate abrupt ending and incorrect beginnings, applying grace notes starting a bar early as a lead in to an instrument beginning or ending. Each Channel allows up to 10 instruments per channel and allows them to be panned and audio balanced. Each Legacy Channel has a 10 channel sub mixer so a single render of a BIAB song can have up to 77 instruments. (PG Music advertises 70 but the sub-Mixer includes the original channel plus the 10 additional sub-tracks.)

The Multitrack BIAB program supports bouncing and sub-mixes. Not only can a user place multiple instruments onto a Legacy Channel, but those multi instrument tracks can be rendered to a Stereo WAV file, imported onto the Audio Channel, converted to a Performance Track and moved onto a Legacy Channel. This process can be repeated multiple times and the final generated render will be a first generation production with no loss or reduction in the audio quality. BIAB's read ahead feature when rendering a track will work the same as the BIAB algorithm searches and selects appropriate forthcoming chord changes. The BIAB algorithm will search out and select appropriate intro and ending transitions between instruments residing on the same channel. With few exceptions, the rendered track will have smooth transitions, fade-in's, fade-out's and sometimes grace notes with both instruments playing simultaneously on the same bar as the transition between them is occurring producing a high quality, commercial grade track that requires multiple tracks and manual editing in a DAW.

The addition of the new Utility Tracks makes multitrack recording with BIAB easier than ever and is well worth the growing pains it's experiencing in my opinion.

Disclaimer: I have no idea how all of the above is done. I'm speculating. But it's of no consequence because simply by applying multitrack/DAW principles and techniques, the process works flawlessly and it's very stable.

BIAB 2025:RB 2025, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.