stereophonically
Two-channel stereophony was a big step forward.
The audio component was a demonstration of the effects of stereophony, reverberation, and echo.
In stereophony, differences of intensity between identical signals from two separate channels (loudspeakers) are used to suggest changes in the location of virtual sound sources.

SMART Vocabulary: related words and phrases

Recording sounds and images
analogue
audiovisual
binaural
binaurally
cut
deepfake
digitally
fast-forward
low-resolution
misrecord
mix
monophonically
play something back
postproduction
prerecord
production
remaster
sample
sampler
videotape