Related Clues:

• Lowered one's voice (with "down")
• -- up (chimed in)
• Part of time signal edited and transmitted by wire
• Taken from place to place, as water music may be
• Made music, as 39-Across did
• Added after a silence, with 'up'
• Spoke assertively, with 'up'
• Brought in by tube, Johnny's back about one
• Conveyed via conduit
• Get the better of journalist introduced by channel
• Like certain music in tube?
• Tweeted, like a wagtail quietly absorbed
• ___ up (spoke louder)
• __ up (spoke)
• Decorated with icing