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275 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Modulation |
Process by which parameters of one signal are modified by another. Used in applications such as telecommunications, broadcasting, synthesis. |
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Carrier signal |
The waveform that is being modulated. |
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Modular signal |
The waveform that is doing the modulating. |
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Bipolar Modulation |
Amplitude -0.5 to 0.5 |
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Unipolar modulation |
Amplitude 0 - 1 |
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Ring modulation |
The simplest form of modulation to implement. Multiplication of a carried signal by a bipolar modulator signal to produce an output. The modulation is perceived at twice modulating frequency because the wave is bipolar. A pair of ‘sidebands’ are introduced around the carrier frequency when the inputs are sinusoids. Neither the carrier or the modulator are audible in the output sound - they cancel out. Otherwise the sidebands will be inharmonic. |
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Harmonic sidebands |
If a sine wave of 600Hz and a sine wave of 200Hz is input then sidebands appear at 400Hz and 800Hz. |
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Reflected sidebands |
When the modulation index is high, sidebands can be reflected at the upper and lower ends of the spectrum. Upper sidebands that exceed nyquist frequency fold back to lower part of the spectrum (aliasing). Lowe sidebands extend below 0Hz are reflected back and phase inverted. If the sidebands coincide with any other partials they will sum with them. This can make the output of an FM synthesiser quite complex in terms of its spectral content. |
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Amplitude Modulation |
A pair of sidebands are created around the centre frequency of each sinusoids component in carrier. The carrier frequency is audible. The sidebands are half the amplitude of the carrier. It’s possible to use other waveforms apart from sine waves. A sawtooth carrier and modulator will produce a waveform with many partials. |
Same algorithm as ring modulation except the modulating wave is unipolar. |
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Frequency Modulation |
Pioneered in the 1960’s by John Chowning. He was experimenting with vibrato and found that very fast vibrato had an interesting effect. A carrier signal is modulated in frequency by a modulator. Low frequency modulator creates vibrato. High frequency modulator introduces sidebands. Using just two sinusoids can generate many sidebands. Can produce complex sounds efficiently. Very effective for imitating brass, woodwind, percussion. |
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Harmonicity ratio |
Determines the frequency relationship between sideband components. h=fc /fm fc = carrier frequency fm = modulator frequency Integer ratios will generate a spectrum with sidebands at harmonic intervals. When this is the case there will be a clear sense of the fundamental pitch in the output sound. Non integer ratios (e.g. 4:1.5) will generate a spectrum with inharmonic sidebands. The output will sound more noisy or metallic when this is the case. |
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Sideband positions |
For simple FM using a single sinusoidal carrier and modulator the sidebands are at: Lower sidebands: [fc - fm] [fc - 2fm] [fc - 3fm] etc. Upper sidebands: [fc + fm] [fc + 2fm] [fc + 3fm] etc. |
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Modulation index |
Determines the amplitude of the sidebands present in the output sound.
I = d/fm d = carrier deviation (Hz) fm = modulator frequency The higher the ______ the more partials are audible (greater spectral bandwidth) |
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Spectral bandwidth |
Can be approximated using the following formula: bw = 2 x (d + fm) d = carrier peak deviation (Hz) fm = modulator frequency |
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Bessel functions |
Amplitude of sidebands follow pattern of mathematical _______ of the first kind. If you know the value of modulation index you can calculate the amplitude of any spectral component. |
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What is the harmonicity ratio with a carrier of 200 Hz and a modulator with a frequency of 100 Hz |
2 |
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What is the modulation index with a modulating frequency of 5kHz and peak deviation of 1kHz? |
0.2 |
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What is the spectral bandwidth with a modulating frequency of 5kHz and peak deviation of 1kHz |
12kHz |
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What is the amplitude of the second sideband pair given a modulation index of 3? |
0.5 |
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Ratio controls |
We have the means of calculating harmonicity ratio and modulation index from given values. However, if we want these ____ as _____on a synth we need to rearrange the equations: d = I x fm fm = fc x h |
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Frequency modulation |
Time varying FM synthesis. The spectral complexity of a note played on most instruments changes over time. Changing the modulation index using an envelope is a very useful way of simulating this. |
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Operator |
Term used to describe the combination of an oscillator and amplitude envelope. |
Fm terminology |
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Algorithm |
Term used to describe the arrangement and interconnection of several operators. |
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FM issues |
A DC offset can occur in carriers or modulators when there is energy from sidebands at 0Hz. DC offset is the mean amplitude displacement of a waveform from zero |
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Additive synthesis |
The creation of sounds by adding together elementary waveforms (e.g. some waves) |
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Additive synthesis |
The creation of sounds by adding together elementary waveforms (e.g. some waves) |
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Complex tones |
Sound waves that consist of multiple superposed sinusoids. If a sound is entirely periodic the frequency of its components are at integer multiples (harmonics) of its lowest frequency (fundamental) The fundamental frequency often corresponds to the perceived pitch While partials (or harmonics) and their relative strength generally attribute to timbre |
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Additive synthesis |
The creation of sounds by adding together elementary waveforms (e.g. some waves) |
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Complex tones |
Sound waves that consist of multiple superposed sinusoids. If a sound is entirely periodic the frequency of its components are at integer multiples (harmonics) of its lowest frequency (fundamental) The fundamental frequency often corresponds to the perceived pitch While partials (or harmonics) and their relative strength generally attribute to timbre |
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Fixed waveform Additive synthesis |
Good for creating static sounds e.g. pipe organ, Hammond organ. |
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Square wave |
fundamental + odd harmonics, amplitude of nth harmonic is 1/n |
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Square wave |
fundamental + odd harmonics, amplitude of nth harmonic is 1/n |
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Sawtooth Wave |
fundamental + all harmonics, amplitude of nth harmonic is 1/n |
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Square wave |
fundamental + odd harmonics, amplitude of nth harmonic is 1/n |
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Sawtooth Wave |
fundamental + all harmonics, amplitude of nth harmonic is 1/n |
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Triangle wave |
fundamental + odd harmonics, amplitude of nth harmonic is 1/n2 |
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Square wave |
fundamental + odd harmonics, amplitude of nth harmonic is 1/n |
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Sawtooth Wave |
fundamental + all harmonics, amplitude of nth harmonic is 1/n |
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Triangle wave |
fundamental + odd harmonics, amplitude of nth harmonic is 1/n2 |
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Time varying Additive synthesis |
Reflects the characteristics of a larger range of ‘real’ sounds. Involves changing synthesis parameters over time using signal modifiers. |
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Square wave |
fundamental + odd harmonics, amplitude of nth harmonic is 1/n |
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Sawtooth Wave |
fundamental + all harmonics, amplitude of nth harmonic is 1/n |
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Triangle wave |
fundamental + odd harmonics, amplitude of nth harmonic is 1/n2 |
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Time varying Additive synthesis |
Reflects the characteristics of a larger range of ‘real’ sounds. Involves changing synthesis parameters over time using signal modifiers. |
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Shepard Tone |
Phenomenon that gives rise to the sound of a constantly rising or descending pitch using additive synthesis. A complex sound that contains partials separates by octaves. This relationship is always maintained however their amplitudes fade in and out over time. Sine wave oscillators could be used to represent the time varying partials. Envelopes could be used to change the relative amplitudes of the partials over time. |
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Parameters required for additive synthesis |
Many oscillators and modifiers can be needed to synthesise complex sounds Inharmonic or noisy parts of sounds are not easy to represent using sinusoids. |
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Subtractive synthesis |
Uses filters to shape the spectrum of a rich source of sound. Instead of synthesising sounds one wave at a time another way is to modify already complex sounds. Assumes the behaviour of an instrument can be modelled by two main components: Excitation source (oscillator) Resonator (filter or bank of filters) |
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Subtractive synthesis |
Uses filters to shape the spectrum of a rich source of sound. Instead of synthesising sounds one wave at a time another way is to modify already complex sounds. Assumes the behaviour of an instrument can be modelled by two main components: Excitation source (oscillator) Resonator (filter or bank of filters) |
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Excitation source |
Vocal cords vibrate as air is expelled through the throat |
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Subtractive synthesis |
Uses filters to shape the spectrum of a rich source of sound. Instead of synthesising sounds one wave at a time another way is to modify already complex sounds. Assumes the behaviour of an instrument can be modelled by two main components: Excitation source (oscillator) Resonator (filter or bank of filters) |
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Excitation source |
Vocal cords vibrate as air is expelled through the throat |
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Resonator |
The vocal tract acts as a filter shaping the source waveform. |
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Subtractive synthesis |
Uses filters to shape the spectrum of a rich source of sound. Instead of synthesising sounds one wave at a time another way is to modify already complex sounds. Assumes the behaviour of an instrument can be modelled by two main components: Excitation source (oscillator) Resonator (filter or bank of filters) |
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Excitation source |
Vocal cords vibrate as air is expelled through the throat |
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Resonator |
The vocal tract acts as a filter shaping the source waveform. |
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Fricatives |
Steady airflow through constricted tract |
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Subtractive synthesis |
Uses filters to shape the spectrum of a rich source of sound. Instead of synthesising sounds one wave at a time another way is to modify already complex sounds. Assumes the behaviour of an instrument can be modelled by two main components: Excitation source (oscillator) Resonator (filter or bank of filters) |
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Excitation source |
Vocal cords vibrate as air is expelled through the throat |
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Resonator |
The vocal tract acts as a filter shaping the source waveform. |
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Fricatives |
Steady airflow through constricted tract |
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Plosives |
Build up of pressure then sudden release |
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Filter types |
Low pass High pass Band pass Band reject |
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Filters in series |
Can achieve sharper responses |
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Filters in series |
Can achieve sharper responses |
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Filters in parallel |
Can achieve complex responses. |
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Channel vocoder |
Sims to extract the spectral shape of one sound then impose it on another. Consists of two stages: analysis and resynthesis. |
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Filters in series |
Can achieve sharper responses |
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Filters in parallel |
Can achieve complex responses. |
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Channel vocoder |
Sims to extract the spectral shape of one sound then impose it on another. Consists of two stages: analysis and resynthesis. |
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Analysis stage |
Source input is passed through a bank of bandpass filters each with a specific frequency/ Q Each filter is tuned to a specific frequency and bandwidth. The output of each filter is routed to an envelope follower Each EF generates a smooth time-varying value proportional to the energy in each filter band. |
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Filters in series |
Can achieve sharper responses |
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Filters in parallel |
Can achieve complex responses. |
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Channel vocoder |
Sims to extract the spectral shape of one sound then impose it on another. Consists of two stages: analysis and resynthesis. |
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Analysis stage |
Source input is passed through a bank of bandpass filters each with a specific frequency/ Q Each filter is tuned to a specific frequency and bandwidth. The output of each filter is routed to an envelope follower Each EF generates a smooth time-varying value proportional to the energy in each filter band. |
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Resynthesis stage |
An excitation signal is passed through an identical bank of band pass filters to the analysis stage. The amplitude of the output signal from each filter is controlled using the value generated by EF. |
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Filters in series |
Can achieve sharper responses |
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Filters in parallel |
Can achieve complex responses. |
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Channel vocoder |
Sims to extract the spectral shape of one sound then impose it on another. Consists of two stages: analysis and resynthesis. |
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Analysis stage |
Source input is passed through a bank of bandpass filters each with a specific frequency/ Q Each filter is tuned to a specific frequency and bandwidth. The output of each filter is routed to an envelope follower Each EF generates a smooth time-varying value proportional to the energy in each filter band. |
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Resynthesis stage |
An excitation signal is passed through an identical bank of band pass filters to the analysis stage. The amplitude of the output signal from each filter is controlled using the value generated by EF. |
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Excitation signal |
Normally a harmonically rich waveform |
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Advantages of channel vocoder |
The ability to separately control source and excitation signal Alter pitch of speech independently of articulation Apply filter response of voice, guitar, to synthesised sounds. |
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Sound |
An air pressure variation that our ear/brain system decodes Sound propagates outwards from a source in a wave like motion through the air. |
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Filters in series |
Can achieve sharper responses |
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Filters in parallel |
Can achieve complex responses. |
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Channel vocoder |
Sims to extract the spectral shape of one sound then impose it on another. Consists of two stages: analysis and resynthesis. |
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Analysis stage |
Source input is passed through a bank of bandpass filters each with a specific frequency/ Q Each filter is tuned to a specific frequency and bandwidth. The output of each filter is routed to an envelope follower Each EF generates a smooth time-varying value proportional to the energy in each filter band. |
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Resynthesis stage |
An excitation signal is passed through an identical bank of band pass filters to the analysis stage. The amplitude of the output signal from each filter is controlled using the value generated by EF. |
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Excitation signal |
Normally a harmonically rich waveform |
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Advantages of channel vocoder |
The ability to separately control source and excitation signal Alter pitch of speech independently of articulation Apply filter response of voice, guitar, to synthesised sounds. |
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Sound |
An air pressure variation that our ear/brain system decodes Sound propagates outwards from a source in a wave like motion through the air. |
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Periodic |
When a wave varies according to a repeating pattern |
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Filters in series |
Can achieve sharper responses |
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Filters in parallel |
Can achieve complex responses. |
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Channel vocoder |
Sims to extract the spectral shape of one sound then impose it on another. Consists of two stages: analysis and resynthesis. |
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Analysis stage |
Source input is passed through a bank of bandpass filters each with a specific frequency/ Q Each filter is tuned to a specific frequency and bandwidth. The output of each filter is routed to an envelope follower Each EF generates a smooth time-varying value proportional to the energy in each filter band. |
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Resynthesis stage |
An excitation signal is passed through an identical bank of band pass filters to the analysis stage. The amplitude of the output signal from each filter is controlled using the value generated by EF. |
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Excitation signal |
Normally a harmonically rich waveform |
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Advantages of channel vocoder |
The ability to separately control source and excitation signal Alter pitch of speech independently of articulation Apply filter response of voice, guitar, to synthesised sounds. |
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Sound |
An air pressure variation that our ear/brain system decodes Sound propagates outwards from a source in a wave like motion through the air. |
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Periodic |
When a wave varies according to a repeating pattern Definite pitch Vowels |
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Aperiodic |
If there is no repeating pattern the waveform is described as _________ Sound more noisy Consonants |
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Sine wave |
The simplest waveform. Single frequency tone that is the building block of all other waveforms (pure tone) |
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Frequency m |
The smallest repetition of a periodic waveform is called a cycle. ______ is the number of cycles that occur per second (Hz) As the length of a cycle increases the number of cycles per second decreases. VV |
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Period (p) |
Time taken to complete a cycle (specified in seconds or ms) Is proportional to frequency (f): p = 1/f f = 1/p |
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Period (p) |
Time taken to complete a cycle (specified in seconds or ms) Is proportional to frequency (f): p = 1/f f = 1/p |
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Wavelength |
Distance from any point on a wave to the same point on the next wave along. Normally measured from crest to crest and specified in meters. |
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Period (p) |
Time taken to complete a cycle (specified in seconds or ms) Is proportional to frequency (f): p = 1/f f = 1/p |
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Wavelength |
Distance from any point on a wave to the same point on the next wave along. Normally measured from crest to crest and specified in meters. |
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Amplitude |
Describes the amount of air pressure change. Sounds with greater _______ produce greater changes in pressure so will sound louder. In a digital system ______ are normally quantised to a fixed range of values between -1 and 1. Precision of this quantisation depends upon the bit depth used. Higher bit depth = greater precision. |
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Period (p) |
Time taken to complete a cycle (specified in seconds or ms) Is proportional to frequency (f): p = 1/f f = 1/p |
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Wavelength |
Distance from any point on a wave to the same point on the next wave along. Normally measured from crest to crest and specified in meters. |
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Amplitude |
Describes the amount of air pressure change. Sounds with greater _______ produce greater changes in pressure so will sound louder. In a digital system ______ are normally quantised to a fixed range of values between -1 and 1. Precision of this quantisation depends upon the bit depth used. Higher bit depth = greater precision. |
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Measures of amplitude |
All samples in a digital audio signal are themselves amplitudes (instantaneous amplitude) However it is useful to have other general measures of amplitude for longer periods of time Peak amplitude RMS amplitude |
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Period (p) |
Time taken to complete a cycle (specified in seconds or ms) Is proportional to frequency (f): p = 1/f f = 1/p |
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Wavelength |
Distance from any point on a wave to the same point on the next wave along. Normally measured from crest to crest and specified in meters. |
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Amplitude |
Describes the amount of air pressure change. Sounds with greater _______ produce greater changes in pressure so will sound louder. In a digital system ______ are normally quantised to a fixed range of values between -1 and 1. Precision of this quantisation depends upon the bit depth used. Higher bit depth = greater precision. |
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Measures of amplitude |
All samples in a digital audio signal are themselves amplitudes (instantaneous amplitude) However it is useful to have other general measures of amplitude for longer periods of time Peak amplitude RMS amplitude |
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Units of amplitude |
Often better compared using ratios than their difference. To facilitate comparisons we often express amplitudes in logarithmic units called decibels. Given an audio signal with a linear amplitude in dB can be calculated using dB = 20 x log10a/a0 ao is a low reference amplitude |
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Controlling amplitude |
In the digital domain this involves simple multiplication of a value with an audio signal sample by sample. |
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Phase |
Describes a point within a waveform as degrees, radians or as normalised value The staffing point on a waveform on the y axis is know as it’s initial phase (0 degrees) |
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Antiphase |
Two waves of the same frequency are combined with each other 180 degrees out of phase causing destructive interference. |
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Antiphase |
Two waves of the same frequency are combined with each other 180 degrees out of phase causing destructive interference. |
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In phase |
Two waves of the same frequency whose cycles exactly coincide are combined causing constructive interference. |
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Antiphase |
Two waves of the same frequency are combined with each other 180 degrees out of phase causing destructive interference. |
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In phase |
Two waves of the same frequency whose cycles exactly coincide are combined causing constructive interference. |
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Duty cycle |
Describes the relationship between the positive and negative parts of the cycle of a wave. A square wave is symmetrical - half the cycle is positive whilst the other half is negative. If we changed this proportion then we would be changing the ________ |
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Partials |
Single frequency components making up a sound Any of the sine waves by which a complex tone is described. |
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Phase Modulation |
Carrier phase is changed by a modulator (not frequency) similar to FM without undesirable side effects |
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Phase Modulation |
Carrier phase is changed by a modulator (not frequency) similar to FM without undesirable side effects |
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PM Advantages |
A DC offset in a ___ modulator does not shift the frequency, it shifts the phase. This allows you to chain together many operators without worrying about pitch drift. The modulation index does not depend on the frequency of a carrier and modulator. The modulation index can be specified directly as modulator amplitude. |
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Harmonic series |
Made up of harmonic partials. Each harmonic has an integer relationship with the fundamental frequency. |
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Harmonic series |
Made up of harmonic partials. Each harmonic has an integer relationship with the fundamental frequency. |
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Instruments |
Most consist of either: Mostly harmonics with small degree of inharmonicity Large degree of inharmonicity but still perceived as being pitched (perc) Unpitched will have many inharmonic partials and no fundamental frequency (Cymbals, tam tams) |
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Sound synthesis |
Process of creating sounds from a network of electronic hardware components or software Widely used in music production for creating unique sounds and recreating instrument sounds. Uses in applications e.g. text to speech software, train station pa, prosthetic voices. |
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Sound synthesis |
Process of creating sounds from a network of electronic hardware components or software Widely used in music production for creating unique sounds and recreating instrument sounds. Uses in applications e.g. text to speech software, train station pa, prosthetic voices. |
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Analogue synthesiser |
________ circuitry to generate sound |
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Sound synthesis |
Process of creating sounds from a network of electronic hardware components or software Widely used in music production for creating unique sounds and recreating instrument sounds. Uses in applications e.g. text to speech software, train station pa, prosthetic voices. |
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Analogue synthesiser |
________ circuitry to generate sound |
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Digital synthesiser |
Computer generated sound |
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Sound synthesis |
Process of creating sounds from a network of electronic hardware components or software Widely used in music production for creating unique sounds and recreating instrument sounds. Uses in applications e.g. text to speech software, train station pa, prosthetic voices. |
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Analogue synthesiser |
________ circuitry to generate sound |
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Digital synthesiser |
Computer generated sound |
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Hybrid synthesiser |
Both analogue circuitry and computer generated sound. |
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Monophonic synthesiser |
Only plays one note at a time |
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Polyphonic synthesiser |
Can play multiple notes at the same time. |
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Oscillator |
Generates a wide variety of waveforms. |
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Analogue oscillator |
Generates sound using electrical components |
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Digital oscillators |
Use different strategies: Wavetable Real-time |
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Wavetable oscillator |
A single cycle of a waveform is stored in a memory buffer called a wavetable. Each sample value in the buffer has an index value which ranges from 0 to n. Computer reads the sample values stored at each index position in turn at the sampling rate. Once it reaches the end of the table it loops back to the start producing a periodic output. |
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Wavetable oscillator |
A single cycle of a waveform is stored in a memory buffer called a wavetable. Each sample value in the buffer has an index value which ranges from 0 to n. Computer reads the sample values stored at each index position in turn at the sampling rate. Once it reaches the end of the table it loops back to the start producing a periodic output. |
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Interpolation |
Estimates what the sample value would likely be if it were there. |
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Wavetable oscillator |
A single cycle of a waveform is stored in a memory buffer called a wavetable. Each sample value in the buffer has an index value which ranges from 0 to n. Computer reads the sample values stored at each index position in turn at the sampling rate. Once it reaches the end of the table it loops back to the start producing a periodic output. |
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Interpolation |
Estimates what the sample value would likely be if it were there. |
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Methods of interpolation |
Linear, cosine, cubic, spline, hermite |
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Wavetable oscillator |
A single cycle of a waveform is stored in a memory buffer called a wavetable. Each sample value in the buffer has an index value which ranges from 0 to n. Computer reads the sample values stored at each index position in turn at the sampling rate. Once it reaches the end of the table it loops back to the start producing a periodic output. |
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Interpolation |
Estimates what the sample value would likely be if it were there. |
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Methods of interpolation |
Linear, cosine, cubic, spline, hermite |
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Real time oscillators |
Involve real time computation of the waveform Rather than read the value of a wave from memory the required value is calculated. |
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Wavetable oscillator |
A single cycle of a waveform is stored in a memory buffer called a wavetable. Each sample value in the buffer has an index value which ranges from 0 to n. Computer reads the sample values stored at each index position in turn at the sampling rate. Once it reaches the end of the table it loops back to the start producing a periodic output. |
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Interpolation |
Estimates what the sample value would likely be if it were there. |
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Methods of interpolation |
Linear, cosine, cubic, spline, hermite |
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Real time oscillators |
Involve real time computation of the waveform Rather than read the value of a wave from memory the required value is calculated. |
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Wavetable synthesis |
Uses multiple wavetables containing different waveforms. A technique employed in many modern day synths as it is capable of creating harmonically rich time-varying sounds. |
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Wavetable oscillator |
A single cycle of a waveform is stored in a memory buffer called a wavetable. Each sample value in the buffer has an index value which ranges from 0 to n. Computer reads the sample values stored at each index position in turn at the sampling rate. Once it reaches the end of the table it loops back to the start producing a periodic output. |
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Interpolation |
Estimates what the sample value would likely be if it were there. |
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Methods of interpolation |
Linear, cosine, cubic, spline, hermite |
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Real time oscillators |
Involve real time computation of the waveform Rather than read the value of a wave from memory the required value is calculated. |
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Wavetable synthesis |
Uses multiple wavetables containing different waveforms. A technique employed in many modern day synths as it is capable of creating harmonically rich time-varying sounds. |
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Wavetable crossfading |
A way of changing/ mixing between each of the wavetables |
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Wavetable oscillator |
A single cycle of a waveform is stored in a memory buffer called a wavetable. Each sample value in the buffer has an index value which ranges from 0 to n. Computer reads the sample values stored at each index position in turn at the sampling rate. Once it reaches the end of the table it loops back to the start producing a periodic output. |
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Interpolation |
Estimates what the sample value would likely be if it were there. |
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Methods of interpolation |
Linear, cosine, cubic, spline, hermite |
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Real time oscillators |
Involve real time computation of the waveform Rather than read the value of a wave from memory the required value is calculated. |
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Wavetable synthesis |
Uses multiple wavetables containing different waveforms. A technique employed in many modern day synths as it is capable of creating harmonically rich time-varying sounds. |
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Wavetable crossfading |
A way of changing/ mixing between each of the wavetables |
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Wavetable stacking |
Same principle as additive |
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Wavetable oscillator |
A single cycle of a waveform is stored in a memory buffer called a wavetable. Each sample value in the buffer has an index value which ranges from 0 to n. Computer reads the sample values stored at each index position in turn at the sampling rate. Once it reaches the end of the table it loops back to the start producing a periodic output. |
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Interpolation |
Estimates what the sample value would likely be if it were there. |
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Methods of interpolation |
Linear, cosine, cubic, spline, hermite |
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Real time oscillators |
Involve real time computation of the waveform Rather than read the value of a wave from memory the required value is calculated. |
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Wavetable synthesis |
Uses multiple wavetables containing different waveforms. A technique employed in many modern day synths as it is capable of creating harmonically rich time-varying sounds. |
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Wavetable crossfading |
A way of changing/ mixing between each of the wavetables |
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Wavetable stacking |
Same principle as additive |
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Modulation switching |
Alternating between each table |
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Wavetable oscillator |
A single cycle of a waveform is stored in a memory buffer called a wavetable. Each sample value in the buffer has an index value which ranges from 0 to n. Computer reads the sample values stored at each index position in turn at the sampling rate. Once it reaches the end of the table it loops back to the start producing a periodic output. |
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Interpolation |
Estimates what the sample value would likely be if it were there. |
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Methods of interpolation |
Linear, cosine, cubic, spline, hermite |
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Real time oscillators |
Involve real time computation of the waveform Rather than read the value of a wave from memory the required value is calculated. |
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Wavetable synthesis |
Uses multiple wavetables containing different waveforms. A technique employed in many modern day synths as it is capable of creating harmonically rich time-varying sounds. |
|
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|
Wavetable crossfading |
A way of changing/ mixing between each of the wavetables |
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Wavetable stacking |
Same principle as additive |
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Modulation switching |
Alternating between each table |
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Envelopes |
Functions of time that can be used to modify synth parameters or signals e.g. Amplitude Frequency Phase Duty cycle |
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Wavetable oscillator |
A single cycle of a waveform is stored in a memory buffer called a wavetable. Each sample value in the buffer has an index value which ranges from 0 to n. Computer reads the sample values stored at each index position in turn at the sampling rate. Once it reaches the end of the table it loops back to the start producing a periodic output. |
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Interpolation |
Estimates what the sample value would likely be if it were there. |
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Methods of interpolation |
Linear, cosine, cubic, spline, hermite |
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|
Real time oscillators |
Involve real time computation of the waveform Rather than read the value of a wave from memory the required value is calculated. |
|
|
|
Wavetable synthesis |
Uses multiple wavetables containing different waveforms. A technique employed in many modern day synths as it is capable of creating harmonically rich time-varying sounds. |
|
|
|
Wavetable crossfading |
A way of changing/ mixing between each of the wavetables |
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Wavetable stacking |
Same principle as additive |
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Modulation switching |
Alternating between each table |
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Envelopes |
Functions of time that can be used to modify synth parameters or signals e.g. Amplitude Frequency Phase Duty cycle |
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Sound modifiers |
Envelopes Filters LFOs |
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Low Frequency Oscillator (LFO) |
An oscillator outputting at a low frequency (<20Hz) Useful for changing synthesiser controls over time |
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Low Frequency Oscillator (LFO) |
An oscillator outputting at a low frequency (<20Hz) Useful for changing synthesiser controls over time |
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Filters |
Modify the frequency content of a single oscillators output or synthesisers output. Boost and cut certain frequencies, cut off frequencies beyond a certain point. |
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Bang message |
Fundamental message type in Max This message tells max objects to execute Normally trigger an objects action when routed to the hot inlet The hot inlet is the left |
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Events |
Max objects communicate by sending each other messages through patch cords. Messages are sent in response to an action by the user or because the event was scheduled to occur. This model of programming can be classed as event driven programming |
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Flow of the program is determined by events such as |
Mouse clicks, keyboard clicks, midi controller input, sensor input, timed events. |
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Max Scheduler |
Runs in the background waiting to detect/ deal with events Refreshes 1000 times per second by default Max waiting time before an event is processed is 1 ms for this control rate |
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Event priority |
All events in max are treated equally. First event in queue is the first to be processed. |
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Event priority |
All events in max are treated equally. First event in queue is the first to be processed. |
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Event priority issue |
When there are many events occurring in a short period of time. |
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Event priority |
All events in max are treated equally. First event in queue is the first to be processed. |
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Event priority issue |
When there are many events occurring in a short period of time. |
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Event priority solution |
Introduce an overdrive option which prioritises events. |
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Event priority |
All events in max are treated equally. First event in queue is the first to be processed. |
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Event priority issue |
When there are many events occurring in a short period of time. |
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Event priority solution |
Introduce an overdrive option which prioritises events. |
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Low priority events |
Mouse clicks, computer keyboard |
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Event priority |
All events in max are treated equally. First event in queue is the first to be processed. |
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Event priority issue |
When there are many events occurring in a short period of time. |
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Event priority solution |
Introduce an overdrive option which prioritises events. |
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Low priority events |
Mouse clicks, computer keyboard |
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High priority events |
Timed events MIDI events |
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Metro object |
Used as a starting point for timed actions It generates a bang message at regular intervals |
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Audio software applications using automated actions. |
Tempo, sequencing. |
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Audio software applications using automated actions. |
Tempo, sequencing. |
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Absolute fixed time (ms) Relative to transport tempo (quarter note, dotted note, triplet) |
Time intervals that metro uses |
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Global Transport |
Max global timing feature. Can sync with other software such as Abelton live or rewire Located in extras menu |
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Timing limitation |
Rate at which timing objects output an event is limited by the scheduler. |
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Message ordering |
Max objects process data in an order that’s dependent on their spatial positioning in a patch and connections. The message ordering rules are: 1. Right to left or bottom to top for vertically aligned objects. 2. All actions on a branch are completed before the next branch is activated. |
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Software bug |
An error in a computer program or system that produces and incorrect or unexpected result. |
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Software bug |
An error in a computer program or system that produces and incorrect or unexpected result. |
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Debugging |
Requires a programmer to observe and interact with a running system in order to gain insight into the process taking place. |
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Software bug |
An error in a computer program or system that produces and incorrect or unexpected result. |
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Debugging |
Requires a programmer to observe and interact with a running system in order to gain insight into the process taking place. |
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Debugging tools in max |
Stop your program at any point in a patch Observe values passing through patch cords Move through your program one step at a time |
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Software bug |
An error in a computer program or system that produces and incorrect or unexpected result. |
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Debugging |
Requires a programmer to observe and interact with a running system in order to gain insight into the process taking place. |
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Debugging tools in max |
Stop your program at any point in a patch Observe values passing through patch cords Move through your program one step at a time |
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Watchpoints |
Allow us to control/ observe working patch |
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Software bug |
An error in a computer program or system that produces and incorrect or unexpected result. |
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Debugging |
Requires a programmer to observe and interact with a running system in order to gain insight into the process taking place. |
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Debugging tools in max |
Stop your program at any point in a patch Observe values passing through patch cords Move through your program one step at a time |
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Watchpoints |
Allow us to control/ observe working patch |
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Watchpoint break |
Enables a program to be paused at a specific point |
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Software bug |
An error in a computer program or system that produces and incorrect or unexpected result. |
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Debugging |
Requires a programmer to observe and interact with a running system in order to gain insight into the process taking place. |
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Debugging tools in max |
Stop your program at any point in a patch Observe values passing through patch cords Move through your program one step at a time |
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Watchpoints |
Allow us to control/ observe working patch |
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Watchpoint break |
Enables a program to be paused at a specific point |
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Watchpoint monitor |
Enables values to be monitored as they pass through a patch cord. |
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Visual programming benefits |
Code is represented by graphical objects Visual representation represents data flow directly Obtain instant sound feedback when developing software Quick to produce a working application - rapid prototyping |
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Visual programming benefits |
Code is represented by graphical objects Visual representation represents data flow directly Obtain instant sound feedback when developing software Quick to produce a working application - rapid prototyping |
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Visual programming cons |
Visual representations are larger than text so screen space is an issue. Challenging to manage complex programs or large data. Algorithms don’t always run as efficiently when compared to text coded version. |
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Visual programming benefits |
Code is represented by graphical objects Visual representation represents data flow directly Obtain instant sound feedback when developing software Quick to produce a working application - rapid prototyping |
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Visual programming cons |
Visual representations are larger than text so screen space is an issue. Challenging to manage complex programs or large data. Algorithms don’t always run as efficiently when compared to text coded version. |
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Text-based programming pros |
Capacity to customise / fine-tune software to a high level of detail Software can run very efficiently in some text based languages You know exactly what processing is going on |
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Visual programming benefits |
Code is represented by graphical objects Visual representation represents data flow directly Obtain instant sound feedback when developing software Quick to produce a working application - rapid prototyping |
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Visual programming cons |
Visual representations are larger than text so screen space is an issue. Challenging to manage complex programs or large data. Algorithms don’t always run as efficiently when compared to text coded version. |
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Text-based programming pros |
Capacity to customise / fine-tune software to a high level of detail Software can run very efficiently in some text based languages You know exactly what processing is going on |
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Text based programming cons |
More abstract, therefore more challenging to learn. Requires knowledge of the computer and it’s operation Need to know about compilation code libraries and other things. |
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Visual programming benefits |
Code is represented by graphical objects Visual representation represents data flow directly Obtain instant sound feedback when developing software Quick to produce a working application - rapid prototyping |
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Visual programming cons |
Visual representations are larger than text so screen space is an issue. Challenging to manage complex programs or large data. Algorithms don’t always run as efficiently when compared to text coded version. |
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Text-based programming pros |
Capacity to customise / fine-tune software to a high level of detail Software can run very efficiently in some text based languages You know exactly what processing is going on |
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Text based programming cons |
More abstract, therefore more challenging to learn. Requires knowledge of the computer and it’s operation Need to know about compilation code libraries and other things. |
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Max |
Uses the concept of modular synthesis where objects are connected with cords in a patch. Data flows through patch cords and in and out of objects in a sequence Each object processes data uniquely. The name of the object describes what it does. Objects can have different numbers of inlets, outlets and arguments. |
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Visual programming benefits |
Code is represented by graphical objects Visual representation represents data flow directly Obtain instant sound feedback when developing software Quick to produce a working application - rapid prototyping |
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Visual programming cons |
Visual representations are larger than text so screen space is an issue. Challenging to manage complex programs or large data. Algorithms don’t always run as efficiently when compared to text coded version. |
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Text-based programming pros |
Capacity to customise / fine-tune software to a high level of detail Software can run very efficiently in some text based languages You know exactly what processing is going on |
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Text based programming cons |
More abstract, therefore more challenging to learn. Requires knowledge of the computer and it’s operation Need to know about compilation code libraries and other things. |
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Max |
Uses the concept of modular synthesis where objects are connected with cords in a patch. Data flows through patch cords and in and out of objects in a sequence Each object processes data uniquely. The name of the object describes what it does. Objects can have different numbers of inlets, outlets and arguments. |
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Arguments |
Allow initial values to be set e.g. a delay of 250ms is set for the delay object below. Arguments are overwritten when a user sends data into an inlet. |
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