Fission

Fission does one job: editing an audio file without degrading it. Trim the silence off the front of a recording, split a lecture into tracks, join a set of files, drop in a crossfade — and when the file is MP3 or AAC, it writes the result back without re-encoding, so the fifth edit sounds like the first. Open the same MP3 in an ordinary editor and export it, and you quietly lose a little quality each time round.

The other half is conversion: MP3, AAC, Apple Lossless, FLAC, WAV and AIFF, in batches, with splitting by silence or by markers, which is what makes tape rips and hour-long interviews bearable to cut up.

$35 gets a key for the current major version, usable by one person across all their own Macs. Fission 2 has been current for years, so the $15 upgrade to some future major is a cheap and distant problem.

This is not a studio. No multitrack, no MIDI, no plugins — reach for a DAW when you need those. And if your editing amounts to two trims a year, Audacity does it free and ugly. Fission earns the money when you handle audio files weekly and care that the tenth save still sounds right.