# Shared Flashcard Set

## Details

music and sound
music and sound
77
Physics
09/30/2012

Term
 what is loudness measured in
Definition
 decibeles (dB)
Term
 another name for fundamental frequency
Definition
 first harmonic
Term
 the greater the number of v ... the higher the f... of the sound that is produced
Definition
 vibrations and frequency
Term
 what does the natural frequency at which a string vibrates depend on T, M.. per ..U, L , L ... of a string
Definition
 tension, mass per unit length and length of a string
Term
 what can harmonics be electronically synthasised using
Definition
 fourier synthesis
Term
 what is fourier synthesis
Definition
 process by which any regular sound can be reproduced by adding regular alternating voltages together
Term
 what is the attack of a sound the measure of
Definition
 measure of how quickly it measures its peak amplitude or loudness
Term
 what is decay a measure of
Definition
 a measure of how long a sound takes to die away
Term
 what is verbrato
Definition
 a periodic change in the pitch of the waveform as the sound continues to be produced
Term
 what is tremolo
Definition
 a periodic change in amplitude
Term
 musicians will often deliberately i .. v .. and / or t .. in order to give expression or variation to music
Definition
 induce verbrato and tremolo
Term
 what do musicians delibertely do to give expression or variation to music
Definition
 induce verbrato and tremelo
Term
 what do sound waves consist of that travel through a substance ( normally air)
Definition
 compression's and rare fractions
Term
 define amplitude
Definition
 maximum displacement from its rest position of one of the particles of the medium that carries the wave
Term
 what kind of wave is sound
Definition
 mechanical
Term
 what does light NOT need to travel through
Definition
 a substance ( in other words it can travel through a vacuum)
Term
 what kind of wave does light travel as
Definition
 an electromagnetic wave
Term
 what is an electromagnetic wave
Definition
 a varying electric field and a varying magnetic field that are at right angles to each other and to the direction of travel of the wave
Term
 what is a transverse wave
Definition
 a transverse wave is one in which energy travels in a direction at right angles to the direction of vibration
Term
 what is the speed of light
Definition
 3.0 x 10 to the power of 8 ms -1
Term
 how many times faster is light than sound
Definition
 light is a million times faster than sound
Term
 what does polarisation of a transverse wave do
Definition
 polarisation of a transverse wave restricts the direction of oscillation so that it only occurs in one place perpendicular to the direction of travel
Term
 why can longitudinal waves such as sound waves never be polarised
Definition
 sound waves travel in the same direction as the oscillation of the particles they travel through and therefor can never polarised
Term
 how do you calculate the speed of sound
Definition
 the speed of sound is equal to the distance in meters divided by the time in seconds
Term
 what is sound formed by
Definition
 S .... is formed by a vibration
Term
 what does sound need to travel through
Definition
 a medium (In other words not a vacuum)
Term
 what kind of wave does sound travel as
Definition
 a longitudinal wave (Travels as S..)
Term
 what is another name for a longitudanal wave
Definition
 a compression wave is another name for a L... wave
Term
 what are compressions
Definition
 regions of higher pressure that their surroundings (What are C..)
Term
 what are rarefractions
Definition
 R ... are regions of lower pressure than normal
Term
 define wave length
Definition
 W .. L .. is the distance between two successive compressions
Term
 what is frequency
Definition
 the number of vibrations per second = F..
Term
 what s frequency measured in
Definition
 HERTZ (measurement of F..)
Term
 what is the equation for finding wave speed
Definition
 C= F x wavelength
Term
 what range of frequencies can the typical human ear detect
Definition
 20 Hz to 20 KHz
Term
 what are frequencies below 20 Hz called
Definition
 infrasound (Below what a human can hear)
Term
 what are frequencies ABOVE 20 KHz called
Definition
 Ultrasound (Above what a human ear can hear)
Term
 what is frequency measured with
Definition
 On oscilloscope (Measures F..)
Term
 what is period
Definition
 a time for one vibration
Term
 what is an oscilloscope calibrated in
Definition
 scmm - 1 (Calibration of Os....)
Term
 scm - 1 is what
Definition
 calibration of oscilloscope
Term
 what is pitch produced from
Definition
 produced from the fundamental frequency plus harmonics
Term
 fundamental frequency plus harmonics produces WHAT
Definition
 Pitch
Term
 what is a pleasant sensation said to be (In regards to hearing)
Definition
 consonant or harmonic
Term
 what forms the basis of the music interval
Definition
 harmonic sound waves
Term
 harmonic sound waves form the basis of what
Definition
 The music interval
Term
 any two musical notes of frequency ratio 2:1 are said to be seperated by what
Definition
 an octave
Term
 the timbre of a wave is made up of what three aspects
Definition
 the harmonics present, attack and decay and vibrato
Term
 what would you use to analyse harmonics
Definition
 fourier analysis
Term
 fourier analysis is used to analyse what
Definition
 harmonics
Term
 what does fourier analysis charachterise harmonics in terms of
Definition
 fourier analysis characterises the wave in terms of the different amplitudes of the frequencies that make up the harmonics of the sound wave
Term
 when a travelling wave is restricted it reflects at each end and forms what kind of wave
Definition
 standing wave
Term
 violins pianos cellos and guitars all have a s .. string that is made to vibrate by either p .. or bowing the string. This sets up a s.. wave on the string.
Definition
 stretched, plucking, standing
Term
 what does resonating mean
Definition
 the air vibrates at the same frequency as the string (Resonates)
Term
 what three things does the pitch of a vibrating string depend on
Definition
 the mass of the string tension of string and length of the string
Term
 the fundamental frequency of a vibrating string is given by what equation
Definition
 f = 1 divided by 2l x square root of t divided by m where l is the length of the string and t is the tension and is the mass per unit length
Term
 define nodes
Definition
 points where the total displacement always remains at zero
Term
 define anti nodes
Definition
 the displacement varies between a maximum in one direction and a maximum in the other direction
Term
 what are the harmonics of a string
Definition
 the number of frequencies at which the string will naturally vibrate
Term
 what is the first harmonic
Definition
 the lowest frequency which a standing wave will be set up and it consists of a singe loop
Term
 what happens to the wavelength when the frequency is doubled
Definition
 it halves and two loops are formed
Term
 why at the open end of a pipe must the standing sound wave be a pressure node
Definition
 at the end of a pipe open to the air, the pressure is always atmospheric and therefore cannot change. this is similar to the fixed end of a string and therefore at the open end of a pipe the standing sound wave must be a pressure node.
Term
 what is known as beats
Definition
 when the frequencies of two waves are similar but not identical a regular rising and falling of amplitude of the resultant wave will be heard. This is known as beats.
Term
 what is the formula for beat frequency
Definition
 fb = f2 - f1
Term
 what is quality sometimes called
Definition
 timbre
Term
 what is the formula for .. energy is found to be proportional to the square of the amplitude
Definition
 ( E funny symbol A squared) doubling the amplitude increases the energy by a factor of four Tripling the amplitude increases the energy by a factor of nine
Term
 what is the formula for finding intensity
Definition
 i = p divided by 4 x pie x r squared. where i is intensity ( Wm - 2) p = power (watts) and r = distances in meters
Term
 what is the quietest sound that a human ear can detect
Definition
 an intesity of around 1 x 10 power of - 12 Wm - 2
Term
 what is pressure measured in
Definition
 Pa (pascels)
Term
 what is the threshold of human hearing
Definition
 the faintest sound a human ear can detect
Term
 what three things can be done to reduce the effect of noise
Definition
 reduce at source, absorb, mask it
Term
 physicists use the term noise to mean what
Definition
 variation of sound or an electrical signal that obscures of reduces the clarity of the signal
Term
 what is the 'common' meaning of noise
Definition
 unwanted sound or noise pollution
Term
 what is the most obvious factor which reduces the effectiveness of ears when responding to sound
Definition
 age
Term
 what does the loudness of a sound depend on
Definition
 the ear of the listner
Term
 what happens to loudness when there is a three decibal increase
Definition
 the loudness doubles
Term
 how do you find out the number of decibals
Definition
 decibals = intensity divided by 1 x 10 power -12 Wm - 2
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