I have experienced the same problem with Total Video Converter. Minus one format for an audio file means that we have removed the vocals from the audio file, which is used for karaoke purposes.
Total video converter can’t be used for this purpose; it’s basically used for compressing the audio file. For converting the mp3 file into minus one, I’d rather suggest that you use the free software called audacity. It’s a 20MB software and easily available on the internet, just Google it.
You just have to follow the following steps:
Import the track.
Split Stereo Track.
Invert one of the tracks.
Mono both the tracks.
For a detailed tutorial, you can refer to this video on YouTube I came across,
While exporting the audio file (which is now minus one), you can select from variety of formats available.