How is the bass drum unpitched?

Answer 1

The term "Pitched", applied to percussion instruments, usually means that the instrument in question produces more than one pitched sound, usually enough to play a melody of some kind. Woodblocks, for instance, can be gathered into groups of five or six, and simple pentatonic melodies can be played on them, but for the most part, they are used rhythmically, rather than for playing song melodies. On the other hand, Orchestra Chimes are gathered into sets at different pitches, sufficient to make at least 2.5 or 3 octaves. Woodblocks are not considered pitched (although each one has a detectable pitch to it) and chimes are considered pitched (even though each chime has considerable extra sound to it besides just pitched components.)

The bass drum could be tuned to a pitch, but it never is. Instead, the two heads are tuned differently, and the gigantic resonant air cavity encourages no particular pitch. Its purpose is to provide a deep-throated boom when it is struck. In actual fact, there is some 'pitchiness' to the sound, but at very very low frequencies, which the ear does not perceive as pitch so much as pressure.

There is really no basis, then that the bass drum would be considered a pitched instrument. Unpitched is the only other choice.

Answer 2

No. Bass drums are tuned and can be tuned to the drummers preference.