Mix-minus

Send a guest the full programme mix and their own voice arrives back at them a moment late, which is unusable to speak over and turns into feedback the instant a microphone is open in their room. A mix-minus fixes it by building a separate feed for that person containing every source in the show apart from themselves. Two remote guests need two of these feeds, each missing a different voice, and the count grows with every caller added. Mixers sold to podcasters generate them automatically, and conferencing software does much the same job quietly through echo cancellation. The term comes from broadcast, where it has been standard on phone-in radio for decades.