Array Instruments in General - Listen to the Array Instruments.
All array instruments are fully chromatic (they have all 12 types of notes) and are played the same way in all 12 key signatures (no matter which notes are used) All the acoustic array instruments may be played as they are, or they may be outfitted with stereo electric pick-ups for electronic amplification or recording.
Harmonic Array Instruments
With instruments designed to have a harmonic array of notes all the differing note types that belong to a particular key signature are united in a particular area while differing note types that do not belong to that key signature are excluded from the area. This allows the individual to play wide ranging harmonies usually only approachable by large orchestras.
Melodic Array Instruments
With instruments designed to have a melodic array of notes all the differing note types that are closest in pitch are closest together, while differing note types that are more distant in pitch are more distantly separated. This allows the individual to play intricate melodies usually only attempted by rehearsed ensembles.
.