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76 Cards in this Set
- Front
- Back
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Fundamental Frequency |
If we record a sound we observe a periodic waveform. Different instruments have different waveforms (harmonic spectra present). The number of cycles of this periodic waveform which occur in one second = the ________ of the note. Pitch of note played Overtones/Harmonics that contribute to timbre/ tone of instrument. |
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Frequency |
Physical measure of vibrations per second. |
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Pitch |
The corresponding perceptual experience of frequency. A subjective characteristic of sound - a psychoacoustic phenomenon characterizes how high or low sound is Is mainly determined by the fundamental frequency but is affected by other factors Quantitative characteristics - the basic unit in most scales in an octave Variation creates a sense of melody |
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Definite pitch |
Harmonic frequency spectra |
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Indefinite pitch |
do not have harmonic frequency spectra |
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Our sense of pitch is influenced by |
Frequency, range, loudness and the presence of other higher or lower frequencies. |
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Pitch Properties |
Must have a certain minimum duration for its pitch to be perceived- otherwise heard as a click Tones with rich harmonic spectra will appear to have a more definite pitch than sinusoids, simpler harmonic spectra, or inharmonic spectra. Very complex inharmonic spectra May appear to have several pitches e.g. in the case of large bells, the fundamental is not the perceived pitch of the instrument, the strike note. |
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Musical pitch |
Represents ‘perceived fundamental frequency’ Description of pitch within harmonic context, tuning system Note-octave pitch representation Grouping according to pitch class, octave & accidental Numerical representation e.g. MIDI |
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Reference pitch |
Pitch inflation Standardised pitch A4 = 440Hz |
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Selected history |
Praetorius, 1619: 424Hz Handel’s tuning fork: 422.5Hz French commission 1859: 435Hz Early 20th century: 431 Hz International conference 1939: 440Hz |
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Absolute Pitch |
is the ability to recognise or produce a particular pitch without using a reference tone. Compare this with vision: most people can recognise the spectral colour red [approximately 2% of the population are colour blind] How many people can recognise a middle C in the same way? [less than 1 person in 10,000] There is no consensus yet on the origin of perfect pitch ability: is it inherited or learned or both? Perfect pitch ability is sometimes also accompanied by synthesis: the innate association of sounds with colours. |
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Relative Pitch |
most people can __________ pitches and this ability can be improved with training. |
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Factors affecting perception of pitch: |
Frequency Sound level Duration Interference from other tones |
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Logarithmic relationship between pitch and frequency |
Doubling of frequency - up 1 octave Halving of frequency - down an octave |
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Sound Level |
Less of an influence than originally thought Pitch perception affected by ________ Above 2kHz perceived rise in pitch as intensity increases Below 2kHz tendency to decrease in pitch as intensity increases Impact on tuning at various levels |
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Duration |
Minimum _____ (number of cycles) to establish pitch required at each frequency. |
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Interference from other tones |
We usually hear different sounds at the same time - not a pure tone in isolation. Experiments around introducing a second tone find that if the second tone has a frequency below (above) the test tone then an upward (downward) shift in pitch perception occurs. There is also an effect due to the relative levels. |
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Noticeable difference of pitch |
we judge them subjectively to be the same, whether they are physically the same or not. Must differ by a minimum threshold for us to distribute them: this threshold is the just noticeable difference (JND) of pitch. The pitch JND is the measure of sensitivity of the ear to changes in pitch. It is sometimes called the pitch difference limen or pitch DL. The size of the pitch JND is not constant: the JND of high frequencies covers a larger span of frequencies than the JND of low frequencies. Pitch JND grows with an increase in frequency [Ernst Weber: the greater the magnitude of a stimulus, the greater must be the change in that stimulus before any difference is detected]. |
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Just Noticeable Difference |
Dependent on Method used to measure it Musical training Frequency |
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Interval perception |
Pitch JND gives us an understanding of pitch similarities, it provides no information about how we judge pitch differences. |
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Theories of Pitch |
Place Theory Temporal Theory |
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Place theory |
Displacement on the basilar membrane If the frequency of a tone doubles, the position of maximum displacement along the basilar membrane moves toward the oval window by a constant amount. This suggests that basilar membrane encodes frequency ratios, not frequency differences. The ______ of pitch, holds that there is a direct relationship between the frequency presented to the basilar membrane and the place along its length that is displaced most strongly. |
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Temporal (Periodicity) Theory |
The timing of neural firings. Supposed that the neural signals from the cochlea to the brain encode timing information related to the phase of the acoustical signal and that the brain has some means of measuring time intervals. Theory notes that the combination of several high harmonica can sum to create a waveform with prominent time domain features whose period is the same as that of their common fundamental. This way a pitch period-measuring capability in the brain would get more or less the same information from a tone with or without a fundamental. |
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19th century pith perception theories |
Helmholtz & Ohm Koenig & Seeberg |
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Timbre |
Sometimes defined as “sound colour” Can refer to aspects of a tone that allows us to identify the instrumental source or the instrumental family, such as woodwinds or strings e.g. to distinguish a saxophone from a trumpet or an oboe from a violin. Used as a way of describing the quality of a musical tone, such a dark, dull, bright, or shrill. |
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Fourier’s theorem |
any periodic vibration, no matter how complicated, can be built up from a series of simple vibrations by choosing the proper amplitudes and phases of these harmonics |
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Fourier synthesis |
Constructing a complex tone from its harmonics. |
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Factors affecting timbre |
Harmonics present Transient effects - starting the note on an instrument, the waveform is not exactly periodic. Formants (centres of resonance causing leaks in spectrum) Envelope (without transient) amplitude, spectral Application of vibrato |
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Harmonics |
The sound from a musical instrument will contain _______ partials. These partials contribute to the timbre of the sound. Clarinet & saxophone can easily be distinguished from each other although both have similar mouthpiece and reed: Cylindrical resonator of clarinet suppressed even harmonics Conical resonator of saxophone allows even harmonics |
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Ratios v Differences |
Ratios of stimuli often come closer to matching up with human perception than do differences of stimuli. Ratios of pressures seem to describe loudness changes better than differences in pressure. |
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Ratios v Differences |
Ratios of stimuli often come closer to matching up with human perception than do differences of stimuli. Ratios of pressures seem to describe loudness changes better than differences in pressure. |
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Logarithms |
Play a key role in modelling and analysing sound. |
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Ratios v Differences |
Ratios of stimuli often come closer to matching up with human perception than do differences of stimuli. Ratios of pressures seem to describe loudness changes better than differences in pressure. |
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Logarithms |
Play a key role in modelling and analysing sound. |
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Logarithmic representation |
Used for decibel scales for amplitude and gain (amplification) Frequency response of the ear or audio devices (spectral analysis) Pitch is logarithmic - each step of the musical scale is a certain ratio of frequencies. |
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Ratios v Differences |
Ratios of stimuli often come closer to matching up with human perception than do differences of stimuli. Ratios of pressures seem to describe loudness changes better than differences in pressure. |
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Logarithms |
Play a key role in modelling and analysing sound. |
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Logarithmic representation |
Used for decibel scales for amplitude and gain (amplification) Frequency response of the ear or audio devices (spectral analysis) Pitch is logarithmic - each step of the musical scale is a certain ratio of frequencies. |
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Audio logarithms |
Logarithms to the base 10 are used. |
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Ratios v Differences |
Ratios of stimuli often come closer to matching up with human perception than do differences of stimuli. Ratios of pressures seem to describe loudness changes better than differences in pressure. |
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Logarithms |
Play a key role in modelling and analysing sound. |
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Logarithmic representation |
Used for decibel scales for amplitude and gain (amplification) Frequency response of the ear or audio devices (spectral analysis) Pitch is logarithmic - each step of the musical scale is a certain ratio of frequencies. |
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Audio logarithms |
Logarithms to the base 10 are used. |
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Log AB = |
Log A + log B |
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Ratios v Differences |
Ratios of stimuli often come closer to matching up with human perception than do differences of stimuli. Ratios of pressures seem to describe loudness changes better than differences in pressure. |
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Logarithms |
Play a key role in modelling and analysing sound. |
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Logarithmic representation |
Used for decibel scales for amplitude and gain (amplification) Frequency response of the ear or audio devices (spectral analysis) Pitch is logarithmic - each step of the musical scale is a certain ratio of frequencies. |
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Audio logarithms |
Logarithms to the base 10 are used. |
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Log AB = |
Log A + log B |
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Log A/B = |
Log A - log B |
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Ratios v Differences |
Ratios of stimuli often come closer to matching up with human perception than do differences of stimuli. Ratios of pressures seem to describe loudness changes better than differences in pressure. |
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Logarithms |
Play a key role in modelling and analysing sound. |
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Logarithmic representation |
Used for decibel scales for amplitude and gain (amplification) Frequency response of the ear or audio devices (spectral analysis) Pitch is logarithmic - each step of the musical scale is a certain ratio of frequencies. |
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Audio logarithms |
Logarithms to the base 10 are used. |
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Log AB = |
Log A + log B |
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Log A/B = |
Log A - log B |
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Log A^n = |
n.log A |
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Ratios v Differences |
Ratios of stimuli often come closer to matching up with human perception than do differences of stimuli. Ratios of pressures seem to describe loudness changes better than differences in pressure. |
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Logarithms |
Play a key role in modelling and analysing sound. |
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Logarithmic representation |
Used for decibel scales for amplitude and gain (amplification) Frequency response of the ear or audio devices (spectral analysis) Pitch is logarithmic - each step of the musical scale is a certain ratio of frequencies. |
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Audio logarithms |
Logarithms to the base 10 are used. |
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Log AB = |
Log A + log B |
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Log A/B = |
Log A - log B |
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Log A^n = |
n.log A |
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Pitch is |
Logarithmic |
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Ratios v Differences |
Ratios of stimuli often come closer to matching up with human perception than do differences of stimuli. Ratios of pressures seem to describe loudness changes better than differences in pressure. |
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Logarithms |
Play a key role in modelling and analysing sound. |
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Logarithmic representation |
Used for decibel scales for amplitude and gain (amplification) Frequency response of the ear or audio devices (spectral analysis) Pitch is logarithmic - each step of the musical scale is a certain ratio of frequencies. |
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Audio logarithms |
Logarithms to the base 10 are used. |
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Log AB = |
Log A + log B |
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Log A/B = |
Log A - log B |
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Log A^n = |
n.log A |
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Pitch is |
Logarithmic |
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Every octave |
Frequency doubles |
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What distinguishes an octave to the ear? |
The ratio of the 2 frequencies |
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Decibels |
Scales widely used to compare and measure powers and related quantities such as sound intensity and sound pressure. Not an absolute number, but a ratio. |
