The english translation of my essay “On Trees and Sounds” is now available for download on my homepage. I wrote the text for the July/August 2010 issue of the German magazine “Neue Zeitschrift for Musik”. It takes the old question: “If a tree falls in a forest and no one is around to hear it, does it make a sound?”, credited to George Berkeley, as a starting point to reflect on various ways to define the term sound. Here are the first two paragraphs:
“If a tree falls in a forest and no one is around to hear it, does it make a sound?” This koan-like question is often quoted in texts on sound and perception, and the answer given is often a counterintuitive no. The argument is as follows: a sound is something created in our brains when our ears perceive the vibration of molecules. Consequently, a sound is nothing but a mental representation in our nervous system, while the sound waves outside our ears are simply part of a larger physical continuum of vibrations. A sound is a product of our sensory apparatus: without ears to hear, no sound.
A similar case can be made in terms of acoustic communication: the production of a sound runs through the classic stages from sound source via medium to recipient. The movement or vibration of a sound source generates sound waves in a surrounding medium such as air, water or solid objects. The sound waves spread concentrically and reach the recipient, who then translates these fluctuations in pressure and density into electrical pulses and perceives them as sounds. If any one of these stages is missing, then there can be no sound. In the absence of a recipient, as in the abovementioned forest, though it is possible to speak in physical terms of a transfer of energy from the falling tree to the surrounding medium, acoustic communication in the sense of an exchange of information does not take place: without a recipient, no transfer of information, and thus no sound.