For percussion, pitch is problematic. Composers and percussionists both wrestle with the challenge of controlling this very important but often indeterminate element of percussion sound, which generates instability of purpose, function, and application. Instability can create problems when attempting to successfully involve these sounds in a musical composition, written or improvised. On the other hand, instability can create novelty, mystery, and surprise; elements that can be powerful components of a musical composition, written and especially improvised.
via NewMusicBox.
