Which of the following is not a musical sound characteristic?

The qualities of sound are as follows: Frequency or Pitch,  Loudness or Intensity, Timber or quality.

The frequency of a sound wave is the parameter that the ear interprets as pitch. A higher frequency sound has a higher pitch, and a lower frequency sound has a lower pitch. The amplitude of a sound wave determines its loudness or volume. A larger amplitude indicates a louder sound, while a smaller amplitude indicates a softer sound. It is the differences that allow us to tell them apart. Timbre is associated with the shape of sound waves or waveforms produced by them. It is obvious from the preceding that wavelength is not a feature of musical sound. As a result, 3 is the right answer.