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What do we know about sound?. Where does it come from?. Vibrating bodies Changing airflow Time-dependent heat sources Supersonic flow. 1. Biological receptors: Pressure changes on eardrums, skin 2. Technical receptors: microphone 3. Mechanical vibrations
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Where does it come from? • Vibrating bodies • Changing airflow • Time-dependent heat sources • Supersonic flow
1. Biological receptors: Pressure changes on eardrums, skin 2. Technical receptors: microphone 3. Mechanical vibrations 4. Other indication (reactions of animals) How do we know it is there?
1. loudness loud, intense vs. soft, silent 2. pitch high pitched vs. low pitched bass vs. soprano 3. timbre or “color” warm, soft vs. shrill, piercing 4. duration How do we characterize sound?
Travels through a medium (gas, liquid, solid) “waves” Medium modifies the sound Distance changes loudness Motion of source or observer changes pitch. How does it get from the source to the receptor?
Physiologically? Is there a place of absolute silence? • Physically? NOISE
We will have to study some Physics fundamentals: Motion, force, pressure, energy, power, oscillations, waves, resonance, … Let’s go! How will we be able to understand some of these observations?