Thursday, September 22, 2016
Class 4
Subject
-Changes in air pressure wave: compression (high pressure) and rarefaction (low
pressure)
-Anatomy of a Waveform
•y axis = amplitude
•X axis = time
•As amplitude increases, so does pressure.
•Characteristics
-Frequency (observed)
•Measured in cycles per second (Hertz) Hz
•Pitch: Perception
•Limits of humans hearing: 20 Hz - 20 KHz
•A4: 440 Hz. A5: 880 Hz
•Sine wave shows amplitude over time
-Amplitude
•Distance above or below centerline of waveform
•Contributes to perceived volume
-Wavelength
•Distance between beginning and end of a cycle
•Period: Time it takes to complete on cycle
-Phase
•Used to specify a particular point in time of a wave form
•Use to compare the relative positions of two waveforms
•We care if waves are in phase and out of phase
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