Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Speech Science
02 Physics of Sound- Intensity
Term | Definition |
---|---|
Sound INTENSITY | The sound pressure of a sound wave is a function of the force with which the object is put into vibration |
force | the degree to which the air molecules surrounding the vibrating object are compressed |
Frequency only changed by | mass |
Intensity changed by | force |
sound pressure is determined by | amplitude of the sound wave (higher the wave higher the sound pressure) |
2 Important Features of the dB Scale | -not an absolute scale. it is a relative scale, that compares one sound to another. -it is a logarithmic scale |
2 Ways to measure sound intensity | Direct - sound intensity level Indirect - sound pressure level |
Formula for calculating decibels | dB SPL= 20 log (pressure of signal/20 microPas) |
The characteristic of a log | The whole number |
The mantissa of a log | The decimal portion |
A tone is presented at a sound pressure of 500 uPa. What is the dB SPL? | dB SPL= 20 log 500 uPa/20 uPa = 20 log(25) = 27.958 dB SPL = 28 dB SPL |
A tone is presented at a sound pressure of 6420 uPa. What is the dB SPL? | dB SPL = 20 log 6420 uPa/20 uPa = 20 log(321) = 20 (2.5065) = 50.13 dB SPL = 50 dB SPL |
A tone is presented at a sound pressure of 940 uPa. What is the dB SPL? | dB SPL = 20 log 940 uPa/20 uPa = 20 log(47) = 20 log(4.70X101) = 20 (1.6721) = 33.442 dB SPL = 33 dB SPL |
2 tones are presented. Tone A produces 100 uPa. Tone B produces 50 uPa. Tone A is how many more dB than Tone B? | relative dB = 20 log 100 uPa/50 Pa = 20 log(2.0) = 20 log(2.0X100) = 20 (0.3010) = 6.02 dB Tone A is 6 dB greater than Tone B |
2 tones are presented -Tone A produces 2970 uPa. Tone B produces 150 uPa. Tone A is how many more dB than Tone B? | Relative dB = 20 log 2970 uPa/150 Pa = 20 log(19.8) = 20 log(1.98X101) = 20 (1.2967) = 25.934 dB -Tone A is 26 dB greater than Tone B |
Created by:
aramos139