CGSC379 Lecture Notes - Lecture 2: Sound, Rarefaction, Audiology
4 Nov 2018
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0,0002 dynes/cm(squared) (smallest amt of pressure to move an eardrum) Movement of air molecules from sound source. Distance a sound wave travels in one cycle. Pure tones (one single isolated pitch) simple sound . Complex sounds (two or more pitches combined) Compression and rarefaction are points of maximum displacement. See figure 2. 7 (compression where molecules are pushed together and rarefaction where molecules are pulled apart), (peak to peak is one wavelength, one cycle per second) # cycles per sec = hertz (pitch/frequency) Larger amplitude = louder sound (larger wave louder sound) Also known as the period of a sound. Humans hear 20 hz to 20,000 hz. Human ear most sensitive to 125-8000 hz (where communication happens/need least amount of pressure) Refers to the level above threshold, used for speech recognition testing (when people can first hear you, go to a comfort (sensation) level) Correction factors needed to compare to db hl. Most often referred to as ehl (estimated hearing level)
