Instruments which are made from sonorous substances.

Instruments in which the sound is produced by a vibrating string; longer, heavier and less tense strings produce lower pitches.

Instruments in which the sound is produced by the vibration of a stretched membrane; heavier, less tense membranes give lower pitches.

The sound is produced by electronic means; this category includes synthesizers and sequencers but not those instruments like electric guitars where an amplifier fulfils the function of a resonator.

Accessories and miscellaneous objects.