Create
Learn
Share

42. Basic terms of physiological acoustics

rename
yaboiemil's version from 2016-02-04 16:46

Summary

 

1. Sound is mechanical Oscillations of an elastic medium
2. Sound may be Musical (PERIODIC) or Non-musical (NOISE)
3. Sound may be just 1 pitch (SIMPLE) or more, or combined Musical/Non-musical (COMPLEX)
4. Sound has Longitudinal Waves in FLUIDS (Gases, Liquids)
5. Sound has Transversal Waves in SOLIDS.
6. Sound is defined by PITCH, TIMBRE and INTENSITY
7. Pitch is to do with the frequency
8. Timbre is the Harmonic Content (e.g. what makes 1 instrument playing Dm diff from another playing Dm)
9. Intensity is the volume (measured in W/m^2)

Facts and Figures

Question Answer
Human hearing range16 - 20,000Hz
Transversal WavesMedium Particles oscillate in a direction perpendicular to wave propagation
Longitudinal WavesMedium Particles oscillate in direction of wave propagation
WavefrontSet of all points in a medium in which elements oscillate with the same phase
WavelengthShortest distance between 2 locations in a medium where elements oscillate with same phase
memorize

Wavelength Equation

 

 

Question Answer
λWavelength
vPhase Velocity in Medium
TPeriod
fWave Frequency
memorize

 

6. The acoustic impedance determines the amount of sound that will be reflected/pass through a medium

Acoustic Impedance Equation

 

 

Question Answer
ρMedium Density
cSound/phase velocity
memorize

Important Definitions

 

Question Answer
Sound IntensityThe amount of acoustic energy that passes through a unit area (W/m^2)
Sound Intensity LevelA comparison of the intensity of 2 sounds (dB)
LoudnessSubjectively Perceived Intensity
Loudness LevelThe intensity needed to louden a sound by the same perceived amount (diff. at different freq due to sensitivity of ear)
PhonUnit of Loudness level. 1 dB at a frequency of 1 kHz
memorize

Sound Intensity Level

 

 

Question Answer
LLevel
IIntensity
I0Threshold Intensity (10^-12 W/m^2)
UnitDecibels (dB)
memorize

Recent badges