downmix

From down- +‎ mix.

downmix (third-person singular simple present downmixes, present participle downmixing, simple past and past participle downmixed)

1. (transitive) To mix (a number of distinct audio channels) to produce a lower number of channels.

• fold down

downmix (plural downmixes)

1. The mixing of a number of distinct audio channels to produce a lower number of channels.

• fold-down

• mixdown