AppVault
Background Music v0.5.0
Per-app volume control for macOS. Finally, turn down just that one loud tab.
Background Music adds per-application volume sliders to your Mac's menu bar. That YouTube tab blasting at full volume while your music is too quiet? Fix each independently. It also auto-pauses your music when other audio starts playing. It's free, open-source, and fills a gaping hole in macOS. The auto-pause feature alone makes it worth installing — no more scrambling to hit pause when a video call starts.