There are two overall categories of musical instrument in NetHack: tonal instruments, which are capable of playing tunes (especially the passtune), and atonal instruments. Both types of instrument have an effect that results when they are applied. Some instruments may not work if you are confused, instead you will get a message that "What you produce is quite far from music..."
Some instruments are magical - they have effects beyond what their ordinary equivalent would yield. When they are uncharged, they behave identically to that equivalent.
|frost horn||Tonal||tooled horn|
|fire horn||Tonal||tooled horn|
|magic flute||Tonal||wooden flute|
|magic harp||Tonal||wooden harp|
|Bell of Opening||Atonal||bell|
|drum of earthquake||Atonal||leather drum|