2. Why does a violin sound different from a horn?

3. Several kinds of audible information Pitch Timbre Attack Decay Vibrato

4. Thus, we need to quantify sound Thus, we need to measure sound We need to systematically compare sounds…

5. The Waveform Plot motion of air (pressure vs. time) time (ms) pressure Microphone converts pressure to voltage

6. Compare Waveforms period T = 2.2 ms T = 7 ms f = 1/T = 140 Hz f = 1/T = 460 Hz

7. pure tone sine wave Single period implies a single, constant frequency Described by only two numbers: f, A amplitude period How can we describe more complicated sounds? simplest soundsimplest waveform