SoundSource
Used by 2 peoplerogueamoeba.com ↗
“And I use SoundSource to quickly change outputs or throw in appropriate EQ for when I'm listening to music or podcasts.”
Stilgherrian Interview, Journalist, podcaster, media producer · via Uses This 
“SoundSource, a replacement for the Sound menu that has superpowers, including per app volume controls and a menu for changing outputs”
André Arko Interview, Web developer · via Uses This