From Longman Dictionary of Contemporary Englishpipe something ↔ in (also pipe something into something) phrasal verbto send radio signals or recorded music into a room or building tunes piped in over an acoustic system → pipe→ See Verb table
Examples from the Corpus
pipe in• He drove out on to Mount Pleasant and was stopped at the temporary lights where the new sewer pipe was going in.• They kept the faucets open, to delay at least, the freezing of the pipes.• The black pipes interlocked in complex patterns from the low ceiling above mountains of mats.• She commenced an impersonation of Hodges, piping inaudible words in effete falsetto, rolling her eyes like a stage Othello.• I piped up in his defense, having had moments to collect my thoughts.• Another example is where a burst pipe occurs in our policyholder's home causing water damage to neighbouring property.• In later years it was fed by a banded iron pipe still in place. 