Coarse crackles are discontinuous, brief, popping lung sounds. Compared to fine crackles they are louder, lower in pitch and last longer. They have also been described as a bubbling sound. You can simulate this sound by rolling strands of hair between your fingers near your ear.
Crackles - Coarse (Rales)

Position: Chest wall
Maneuver: Seated
Chestpiece: Diaphragm