Final answer:
The pair of terms that do NOT belong together is 'amplitude; pitch', because amplitude is related to loudness, not pitch, which is determined by frequency.
Step-by-step explanation:
The pair of terms that do NOT belong together is amplitude; pitch. Amplitude is related to the loudness of a sound, whereas pitch is related to frequency. Complexity is indeed associated with timbre, which refers to the quality or color of a sound that makes it distinguishable from others, even if they have the same pitch and loudness. In the visual system, hue is associated with wavelength; therefore, this pair is correctly matched. Thus, amplitude and pitch are not directly related, making option 1 the correct answer.
It is important to remember that, pitch is perceived by the frequency of the sound wave, while loudness corresponds to the amplitude of the wave. The timbre of a sound is a result of its waveform, which includes the fundamental frequency and harmonics, shaped by the amplitude and timing of the sound waves.