Hand-stopping is a technique by which a natural horn or a natural trumpet can be made to produce notes outside of its normal harmonic series. By inserting the hand, cupped, into the bell, the player can reduce the pitch of a note by a semitone or more.
Hand-stopping is a technique that enables a natural horn or natural trumpet to produce notes beyond its standard harmonic range. By inserting the hand, cupped, into the bell, the player can decrease the note's pitch significantly.