Some forum members use Cakewalk's TTS-1 32 bit soft synth as their default MIDI sound source in Band-in-a-Box.

Did you know: Ucheck all midi outputs in preferences and TTS-1 will automatically load up when you OPEN any midi file. Makes it super easy to preview midi song files.

I found this little nugget in a Cakewalk forum post.

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Jim Fogle - 2024 BiaB (1111) RB (5) Ultra+ PAK
DAWs: Cakewalk by BandLab (CbB) - Standalone: Zoom MRS-8
Laptop: i3 Win 10, 8GB ram 500GB HDD
Desktop: i7 Win 11, 12GB ram 256GB SSD, 4 TB HDD
Music at: https://fogle622.wix.com/fogle622-audio-home