MUS 191L Lecture Notes - Lecture 2: Sound, Sound Pressure, Record Producer
Document Summary
Mus 191/l lecture #2 sound, waveforms, and amplitude. Sound: sound - produced when something vibrates or oscillates in the air, sound pressure waves are periodic vibrations in atmospheric pressure. Smaller, contained type of energy (vs weather atmospheric pressure: compression = more dense air (higher pressure, rarefaction = less dense air (low pressure) The waveform view: a graph of the change in air pressure of a sound wave over time, most basic = sine wave. No instruments produce sine waves - all produce overtones. Amplitude: amplitude = y-axis of wave graph (full cycle, up and down, greater distance from center line, greater intensity (loudness, measured in decibels (db) Threshold of pain = 120 db: db spl (sound pressure level) Frequency: frequency = x-axis of graph, rate at which a waveform repeats itself (cycles in a given space, measured in hertz (hz) [hz = cycles per second]
