[jay-n-123]

Saw the YouTube video of The Police performing Roxanne live at Grammy's.
Clearly they used pre-recorded background vox of Sting.

Was wondering if that means the playback of the background vox was entirely
automated beforehand..which would mean that the length of "jam" sections in
song were rehearsed?

Or did they have a guy simply press a button to trigger the samples at the
correct moments in time?

Did they need to use a click track even if the latter method were used? It
seems to me if the sample playback device were sophisticated enough to let
you tap in a target tempo in real-time, and if they had a guy backstage tap
in the exact target tempo in real-time during the song, and the guy pressed
the "trigger sample" button at exact locations, then the band wouldn't need
a click track since the device could time stretch or compress the sample
speed to match target tempo. Does such a sample playback device
exist?...or would using it be too risky of causing a glitch? (such as
tapping in the wrong target tempo by mistake...yikes)

J.