Indispensible and Morphophoric

A similar AUDIO example with two loudspeakers:

1. one loudspeaker plays middle C and the other middle E--one source is heard on the left, and one on the right;
2. both pitches change to middle D--single source is heard located between two loudspeakers;

Figure 5: Two speakers carry two notes (left); one speaker carries two notes (center); two speakers carry the same note and there are no longer two notes (right).

Pitch is thus indispensable and NOT analogous to color:

• the analog to visual space is not auditory space, but auditory pitch;
• visual space and auditory pitch are morphophoric media.