Possible Clues:

• Need ears free for piece of music
• Victor Herbert operetta, with 'The'
• Evening music (played outside woman's house)
• Need ears tuned to this?
• It's played or sung at a lover's window
• Unperturbed about modern-style music
• Bars outside the window
• Activity at a sorority
• A little night music
• Sing to a lover, or the song itself