SlackBuildsOrg/audio/transcribe

transcribe (music transcription tool)

The Transcribe! application is an assistant for people who sometimes
want to work out a piece of music from a recording, in order to
write it out, or play it themselves, or both. It doesn't do the
transcribing for you, but it is essentially a specialised player
program which is optimised for the purpose of transcription. It has
many transcription-specific features not found on conventional music
players.

Transcribe! is proprietary software. After installation, Transcribe!
will be fully functional for a 30-day evaluation period. To buy the
software, use the site at http://www.seventhstring.com/xscribe/buy.html.
The Slackware package doesn't need to be changed or updated (just
enter the license key).

Note: I'm aware that there's a newer version (9.10.0), but it crashes
on startup, most likely due to incompatible library versions. Will
revisit this when Slackware 15.0 is released.