and cannot carry a tune; can't carry a tune in a bushel basket; can't carry a tune in a bucket; can't carry a tune in a paper sack
Fig. [to be] unable to sing a simple melody; lacking musical ability. I wish that Tom wouldn't try to sing. He can't carry a tune.I don't know why Mary's in the choir. She can't carry a tune in a bushel basket.Joe likes to sing in the shower, though he can't carry a tune in a bucket.I'd try to hum the song for you, but I can't carry a tune in a paper sack.