The Ins and Outs of Audio

Introduction
• There once was a time when the word “audio”
referred only to pressure variations in air
– For most people, sounds heard as musical tones have a frequency
range of about 32 Hz to 8 kHz (-3 to +5 octaves from middle C)
– Sounds outside of this range can also be heard, but not necessarily
as musical tones (e.g. thunder, breaking glass, drums, cymbals)
• Perhaps the very earliest form of audio “processing”
consisted of acoustic wave shaping dating back to the
Greeks in the 4 th century BC
– A small megaphone was sometimes built into player masks
– Amphitheater design (e.g. see Epidaurus on the Peloponnese)
– The “Ins” and “Outs” were simply the acoustic signal itself