Possible Clues:

• Lyric track, in studio-speak
• -- populi (popular opinion)
• Lyrical track, to a producer
• It came out of Cicero's mouth
• ___ populi (voice of the people)
• __ populi (popular opinion)
• Wah-wah pedal maker
• Classical-music record label
• Voice of old Rome
• Media site that publishes "explainers"