Ai comes up with this method, which may or may not be accurate. Worth a try...
To split a single FLAC audio file containing 12 tracks into separate FLAC files using NCH Switch Audio Converter, you will need a corresponding .cue file. Here’s how to do it:
Ensure you have both the large FLAC file and its associated .cue file in the same folder. The .cue file contains the track information needed for splitting.
Open NCH Switch Audio Converter.
Click on the "Add Files" button and select the .cue file. This should automatically load the individual tracks from the FLAC file into the program.
At the bottom of the main window, select "FLAC" as the output format to maintain lossless quality.
Under "Save to Folder," specify where you want the converted (split) files to be saved. You can choose the same folder as the original or a new directory.
If needed, click on “Encoder Options” to customize settings like compression level or sample rate for FLAC files.
Click on the "Convert" button. Switch will process the .cue file and create separate FLAC files for each track.
If you do not have a .cue file, you may need to create one manually or use another tool like CUETools or Foobar2000 to generate it before proceeding.
Ensure your version of Switch supports .cue files; some features may require a licensed version of the software.
This method ensures that each track is split accurately while preserving audio quality.