This is a common language which enables any MIDI-equipped electronic instrument to be linked together
MIDI-equipped instruments connect to each other using standard MIDI cables (5-Pin DIN plugs on each end)
To generate sound by generating electrical signals which decides what note is to be played and how loud it will be. The moment when a note is pressed a 'Note On' message is sent, when it's released a 'Note off' message is sent. The 'Note on' message contains the velocity (the speed on the note pressed, affected by how hard it was hit) which affects the volume of the note played.
A MIDI synthesiser has two wheels which are mounted onto the keyboard. Two general effects used would be Pitch bend and Vibrato. they work by creating electrical signal which will create the sound.
MIDI have access to up to 128 controls patches (0-127) and these enable program change information to be transmitted and can be used to switches effects.
Quantise is a common feature used to be able to correct timing issues and notes get pushed to the closest subdivision of a bar. it can be used to create a swing fill or there are many other features like humanise which can change the velocity and timing of the inputted notes on a Piano roll and will make it sound more realistic, as quantise can make the sound seem too robotic.
Slide 2
Subtractive Sythnesisers
This is a method which allows partial parts of an audio signal to be attenuated by filters to alter the timbre of the signal.Some features found on a subtractive synthesiser will be: Low-Pass: Removes frequencies above the cutoff frequency. Makes waves sound darker or muddier.
High-Pass: Removes frequencies below the cutoff frequency. Makes waves sound brighter.
Band-Pass: Lets a narrow band of frequencies centered around the cutoff frequency through.
Notch / Band-Reject: Removes a narrow band of frequencies centered around the cutoff frequency.
Slide 3
Oscillators: generates
the basic signal, and will generally be rich in harmonics. many
synthesisers will have more than one oscillator.
Filter section: Used to alter the basic signal by
filtering portions of the frequency spectrum. Many
synthesizers use a single filter, and that can be used on all
oscillator signals. Multioscillator synthesizers give multiple
filters, allowing each oscillator signal to be filtered differently.
Amplified section: Controls the level of the signal. The envelope
(amplifier feature) is broken down into several components which provide
level control
for the beginning, middle, and end portions of the sound. More complex
synthesizers have multiple envelopes
Modulation:
Modulates the signal-generating and processing components. It can come
as a machine-based (automatically generated by a
synthesizer component) or manually activated by using the
modulation wheel e.g. An LFO (low frequency oscillator) which creates
waveform that modulates the signal.
Slide 4
Synths timbres
Timbre is 'the character or quality of a musical sound or voice as distinct from its pitch and intensity.'Synths can change the timbre of a sound by Additive synths which can change the waveform of a sound (Sawtooch, Triangle, Square waveform etc.) and give a signal a different soundModulation will change the amplitude and the harmonics. Some examples of features that do this is LFOs and Vocoders which allows the change of the harmonic and signal structureEnvelopes gives access to change the attack, decay, sustain and release of the instrument.
Caption: : An example of ADSR and how it manages different elements of a sound
Slide 5
Global parameters
Glide: the amount of time it takes a note to slide up
or down to another note pitch. It can help make wind instruments or ones that use glides to sound more realistic.
Bender: This is also know as the Pitch bend wheel and it moves up or down bending the pitch (the oscillator frequency) up or down. It comes with an upper and lower limit of one
octave but this can vary. This
setting is useful for instruments such as live electric guitars.
Voices: Synthesizers
have a limit to the number of notes that can be produced
simultaneously (polyphony). The Voices
parameter sets an upper limit to the number of notes that can be played
at a given time.
Unison: Used
to “stack” voices—with the unison voice being heard one octave above
the frequency of the played note. Because two voices are being used when
you play a note, unison has two effects—it makes the sound richer and
fuller, and it halves the polyphony.
Trigger Mode: How the polyphony of the instrument is handled there is more than the available amount of voices. It can create many different sounds such as legato. Trigger mode responds to your playing technique.
Slide 6
Filters
Logic offers many different features for filtering which allows manipulation of the sound.The parameters on a filters are:
Threshold parameter: if the input level exceeds this level it triggers the envelope or LFO, which dynamically modulate the filter cutoff frequency.
Envelope parameters: How the filter will modulate the cutoff frequency over time
LFO parameters: How the filter cutoff frequency modulates by the LFO
Filter parameters: Controls the tonal color of the filtered sound.
Distortion parameters: Distort the signal both before and after the filter.
Output parameters: Set the level of both the dry and effect signal.
An LFO is a modulation source that produces a repeating signal.
The most important parameters for programming an LFO are waveform,
frequency, destination, and amplitude. The term rate is often used in
place of frequency, and depth is used in place of amplitude.
The frequency of a low-frequency oscillator is, by definition, low. Some
LFOs can produce signals having a frequency as low as 0.02 Hz (one
cycle every 50 seconds). The upper frequency limit for many LFOs is
around 20 Hz. Some LFOs can produce frequencies above 20 Hz, but when
that type of signal is used for modulation, the result is a buzzy sound
that covers up the individual cycles of the LFO waveform.
