NATS 1720 Lecture Notes - Lecture 22: Critical Band, Basilar Membrane, Musical Tone
9 Dec 2018
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Document Summary
Response of basilar membrane to a pure tone is spread over a range about 1. 2 mm long. Corresponds to the critical band of frequencies around that tone. About 15% of centre frequency above 500 hz. Radiator (eg. body of guitar, flared bell, open finger holes) 6 strings about 66 cm long with different linear density=> different open string pitches. Higher harmonics are weaker, dropping in strength quickly. Woodwinds change pitch by opening/closing finger holes and register key. Brasses change pitches by overblowing (forcing a resonance at higher harmonic), and by adding length to the pipe: resonator. Mouthpiece converts a continuous stream of air into an oscillating one (to drive resonator) Air flow cause reed to vibrate at its natural frequency. Feedback from pipe locks reed frequency to that of pipe. Air flow directed against an edge oscillates between both side of edge, creating + and pressure pulses.
