Comm Diss 311-page67

Comm Diss 311-page67 - c. 58 dB SPL and 62 dB SPL d. 66 dB...

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5 4.6. How many dB SPL is a. 2 dynes/cm 2 b. .0004 dynes/cm 2 c. 2 x 10 -3 dynes/cm 2 d. 4 x 10 2 dynes/cm 2 e. 6.5 dynes/cm 2 f. .01 dynes/cm 2 4.7. If the sound pressure measured with a microphone at the entrance to the ear canal is 8 x 10 -3 uPa and the same sound measured at the eardrum is 3.2 x 10 -2 uPa, what is the difference in decibels between these two microphone positions? 4.8. A sine wave with a frequency of 200 Hz, a starting phase of 0 degrees, and a peak amplitude of 5 volts is amplified by 12 dB. Redraw the sine wave. 4.9. What is the intensity in watts/m 2 of a sound that has an RMS pressure of 4 dynes/cm 2 ? 4.10. Two or more noises with the SPLs specified are added. What is the total SPL for each of the cases below. a. 52 dB SPL and 60 dB SPL b. 56 dB SPL and 60 dB SPL
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Unformatted text preview: c. 58 dB SPL and 62 dB SPL d. 66 dB SPL and 67 dB SPL e. Four machines each producing 80 dB SPL f. Fifteen machines each producing 70 dB SPL. g. Forty machines each producing 90 dB SPL. 4.11. When four Air Force Thunderbird F-16s take off together in tight formation, the noise for the Air Show spectators is deafening, about 115 dB SPL. If a solo F-16 takes off, what is the predicted noise level for the spectators? 4.12. Within 1 dB, what is the total SPL produced by the sum of the following sound sources? Source 1: 80 dB SPL Source 2: 77 dB SPL Source 3. 77 dB SPL Source 4. 83 dB SPL Hint: See if you can figure it out by just looking at it, then do the calculations....
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