Possible Clues:

• Crying sound
• "Do ___ Diddy Diddy"
• When repeated, a trombone sound
• Comic strip cry
• Crybaby's sound
• 'Do ___ Diddy Diddy' (1964 #1 hit)
• Trumpet's sound
• 'Do -- Diddy Diddy'
• When doubled, a guitar or horn effect
• ''Do __ Diddy Diddy'': 1964 hit