SOUND THEORY 1 Flashcards
What is sound?
Sound may be described as a physical or as a perceptual phenomenon.
What are the two sound phenomenons?
Physical and Perceptual
Describe physical sound phenomenon.
Sound may be defined as a periodic fluctuation in pressure above and below a normal stable level.
Describe perceptual sound phenomenon.
sound may be defined as the perceived effect of a
periodic fluctuation in pressure within a specific range
Sound does not _____ in _____ or through ______ at ______ degrees in temperature
Sound does not propagate in vacuum or through media at absolute zero degrees in temperature
Pressure above a normal stable level is called?
Compression
Pressure below a normal stable level is called?
Rarefaction
What is the speed of sound?
The speed of sound is affected by the temperature, elasticity and the density of the
medium through which it travels
Speed of sound is directly proportional to?
Temperature
Speed of sound is greater in?
More elastic states
Speed of sound is inversely proportional to?
Density
What is the formula used for speed of sound?
c = 331 + (0.6t) in air at sea level / Speed = 331 + (0.6temperature)
Speed is the ratio between ____ and the amount of ____ taken to cover it.
Speed is the ratio between distance and the amount of time taken to cover it.
What is the ‘equating speed and the distance covered by sound’ formula?
c = d / t (speed = distance / time)
What formula do you use to find the distance?
d = c * t (distance = speed * time)
What formula do you use to find the time?
t = d / c (time = distance / speed)
What is amplitude (A)?
Is the amount of deviation from normal atmospheric pressure
What is frequency (f)?
Is the number of complete cycles of pressure fluctuation that occur in one second, expressed in c.p.s. or Hertz e.g. one cycle per second is referred to as one Hertz.
What is Period (T)?
Is the amount of time necessary for one full cycle to take place.
T = period (s) f = frequency (Hz)
What is the formula to find the period?
T = 1/f
How do you find the frequency using the period formula?
f = 1/T
What is the first way to describe a wavelength?
As the distance traveled by sound during one period
What is the second way to describe a wavelength?
As the distance between any two consecutive, corresponding points along a waveform
What is the formula used to find a wavelength?
λ = c / f
How do you find the frequency, using the wavelength formula?
f = c / λ
How do you find the speed of sound, when using the wavelength formula?
c = f x λ
Phase is used to describe?
The different points along a waveformʼs cycle
The relationship or interaction between different sound waves or audio signals
What is the formula used to find the phase shift?
Ø = ∆t x 360 x f
Comb filtering is the effect of alternating ______/______ at different _______ when _______ time-displaced versions of a complex sound reach a common _____ in space.
Comb filtering is the effect of alternating reinforcements/cancellations at different frequencies when multiple time-displaced versions of a complex sound reach a common point in space.
The sine wave components of a sound are described as ?
Partials
Partials are divided into
______, _____ (integer multiples of the fundamental) and other _______
Partials are divided into
fundamental, harmonics (integer multiples of the fundamental) and other overtones
The collection of all partials is called?
The sound spectrum.
Sine waves consist of?
A single, fundamental frequency or first harmonic
Sawtooth waves consists of?
all harmonics at decreasing amplitudes
[y = sin (x) +1/2 sin (2x) + 1/3 sin (3x) + 1/4 sin (4x) + … ] This represents?
A sawtooth wave
Square waves consist of?
odd harmonics at decreasing amplitudes. A square wave is one type of pulse wave
[y = sin (x) +1/3 sin (3x) + 1/5 sin (5x) + 1/7 sin (7x) + …] This represents?
A square wave
Triangle waves consist of?
odd harmonics alternating in polarity and with steeper decreasing amplitudes (in relation to square waves)
[y = sin (x) - 1/9 sin (3x) + 1/25 sin (5x) - 1/49 sin (7x) + …] This represents?
A triangle wave
