"Play a note on almost any musical instrument, a piano, say, or your own voice, and it will carry a range of frequencies that correspond to the central pitch. Those that form a regular arrangement -whole multiples of the base frequency — are called harmonic. Frequencies in bells on the other hand, are not harmonic. A curious fact emerges.
"Put simply, the pitch we hear when a bell is played, in contrast to those in pianos, voices, stringed instruments, and so on, does nor always correspond to any actual frequency present in its sound. If you hear a middle C in the sound of a bell, say, there is no guarantee that a frequency matching that note is in fact being transmitted through the air. Rather, the experience of hearing a middle C is an epiphenomenon, a kind of ghost: it is the mind's attempt to make sense of the richly dissonant vibrations produced by the instrument. The analogy doesn't quite fit, but it would be a bit like looking at a painting and seeing a vivid blue, where no blue paint has been used. The pitch heard in bells is virtual. It is generated inside the listener's head, an impression of something which is not there, frequencies surrounding an absence. This purely subjective quality offers one explanation as to why, in my experience, bells are so effective in the treatment of psychic distress." --Patrick Langley, The Variations (2023)
