Chapter 2 - Sound Flashcards
Define pitch.
A characteristic of sound through which we differentiate between shrill and grave sound. It is not a physical characteristic, so it cannot be measured directly. It is essentially the perception of frequency and depends upon the wavelength and speed of sound.
Pitch describes the number of vibrations produced by vocal chords in unit interval of time (1 sec). This os why it is related to frequency: it is proportional to it.
Low pitch waves mean less frequency while higher means vice versa.
Define “loudness”
Not a physical quantity, measured instead on the basis of amplitude. Which means that it tests the strongest levels of aound waves, and is studied in decibel.
Loudness is proportional to (amplitude)^2
It can also be described at being dependent upon the energy receuved by the ears in unit time interval.
What 4 factors effect the loudness of sound?
Vibrational amplitude, surface area of the source of sounds (to which it is proportional to ala more SE = More sound), Distance from the source of sound and the sensitivity of the ears of the listener.
What is timbre?
It helps us differentiate between the quality of sound waves with the same pitch and loudness. It helps us study dynamic characteristics as well as harmonic contacts of sounds. The quality of sound depends pn relative overtones, which means a harmonic frequency greater than the frequency of the sound.
What is harmonic contact?
Harmonic contact means that during the motion of sound, the pathway of kinetic transmission is followed by the molecules of the medium for transmitting energy.
What is meant by the intensity of sound wave?
Energy transmitted by sound wave per unit perpendicular area pwr unit time. Represented by “I”.
Energy transmitted / Area × time = E /A × 1 = P / A
In other words, the intensity of sound wave is the power delivered by the soind wave per unit perpendicular are. Its units are watt / metrw^2 (W/m^2)
What is the relation between amplitude and the intensity of sound waves?
(Change in amplitude developed by pressure)^2 / 2 (density of medium) (speed of sound) = I = (A)^2 / 2pv
Factors of sound propagation that affect the speed of sound.
Temp: Imcrease in 1c of temp inceases sound speed by 0.62 m/s.
Vt = V0 + 0.61, where V0 = 332 m/s
Dynamic state of medium: If wind is blowing, sound will be fast as well.
Viscosity of medium: Speed does not depend on viscosity itself, but the term suggests resistance in viscous substances that tends to change the behavior of molecules.
Characteristics of Noise.
Non-rhythmic
graphical waveform shows variable
energy states.
Wave form in the graphs of noise suggest multiple frequencies
Graphs shows irregular intensities of distribution.
What is an echo?
The bouncing back of sound due to the wave reflection phenomenon. It is a distinct sound with a separate wave from the original noise. The hardness of echoes is not very high, and it prolongs the sensation of listening to the original sound.
By an echo, the distance of any object under water can be calculated by multiplying the speed of sound by the time taken by the echo.
Human ears can generally hear sound waves within 0.1 second, so the time interval gap between sound and echo is 0.1 second. The maximum distance required for the production of an echo is 1/20th times the value of the speed of sound. For example, if the sound is 332 m/s for the production of echo, its distance would be 16.6m
How is the speed of sound related to temp?
Speed of sound at any temperature is given by 331 + 0.6T
Why do spectators hear the sound of impact after the ball is hit by a batsman playing cricket in a stadium?
Because sound travels at a rate of 340 ms^-1 in the air, which is why it is heard as delayed.
