Accompanrment, as when a group of vocalists record a “backing track” to which the soloist listens on headphones when recording.
"I am extremely delighted with my new CD. Several of the songs on the LP were never made available on a CD, but there was one song in particular I remembered and wanted to hear again. I wasn’t certain about the technical details when offered a choice of sound quality, so I left it to your team of experts. I considered an LP to CD transfer ..."