CoachPitch is the perception of frequency: the higher , the higher the note; concert A is , and doubling raises the note one octave. Loudness is the perception of amplitude: the stronger the pressure oscillation, the louder; amplification changes loudness, not pitch.
Examples
Example 21.15 (Why you recognize the caller)
A flute’s A is nearly a pure tone; a violin bowing the same adds strong harmonics at . Same pitch and loudness, yet no one confuses them: a voice, too, is a spectrum you know by heart.