Mono or stereo audio files depend on your audio interface and the recording and audio file export settings in Cubase. Most DAWs default to exporting an audio file in the same mono / stereo track format the audio was recorded in. In other words, mono signal in then mono track out; stereo signal in then stereo track out.

Some audio interfaces duplicate an input and send a monophonic signal to both the right and left outputs so a DAW records a stereo track even though it is recording a monophonic instrument. Others default to one audio input feeding the right channel while the other input feeds the left channel. When DAWs are forced (through default or user settings) to record a stereo track with a monophonic input, one channel will have a waveform while the other channel will have a flat line.

There is no standard for how audio interfaces routes input signals. Unfortunately bit depth has nothing to do with an audio file being mono or stereo.

What are you recording; vocal or what instrument? Are you using one or more microphones? What audio interface are you using? Have you looked at your exported audio file waveform(s) with any other program beside Band-in-a-Box?

Jim Fogle - 2025 BiaB (Build 1128) RB (Build 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