Synthesisers

What is the definition of a synthesiser?

An electric sound generator capable of creating and manipulating synthetic sounds.

What are the two different types of synthesisers?

DAW plug-ins, vintage analogue equipment.

How does a synthesiser work? (Diagram)

What is the function of the oscillator?

Generates an initial sound, and allows you to choose a wave shape.

How can differing wave shapes be used to create different timbres?

Each wave shape has different harmonic content.

What are the 6 different wave shapes?

Sine wave

Triangle wave

Sawtooth wave

Square wave

Pulse wave

Noise

Describe the sound of a sine wave, and its uses.

Sound - pure tone

Uses - basic building block of sound

Diagram of sine wave

Describe the sound of a triangle wave, and its uses.

Sound - slightly harsher than a sine wave

Uses - flute-like sounds and pads

Diagram of triangle wave

Describe the sound of a sawtooth wave, and its uses.

Sound - even and edgy

Uses - strings, basses, pads and brass/dance leads

Diagram of sawtooth wave

Describe the sound of a square wave, and its uses.

Sound - Hollow and woody

Uses - clarinets, oboes and bass sounds

Diagram of square wave

Describe the sound of a pulse wave, and its uses.

Sound - nasal sounding

Uses - Reed instruments and basses

Has a variable pulse width/mark-space ratio

Diagram of pulse wave

Describe the sound of noise, and its uses

A noise generator creates a random signal.

White noise consists of all frequencies at an equal amplitude. Other colours of noise have different frequency distributions.

Uses - can be used to stimulate wind

On a synthesiser, what does the oscillator first allow you to do?

Select an octave.

This is often achieved by choosing between numbers like 4,8,16 and 32 - origins on organ pipes.

What are the two further tuning controls on an oscillator?

Coarse tuning - sets the pitch in semitones

Fine-tuning - measured in cents (100 cents in a semitone)

True or false, many synthesisers have more than one oscillator?

True.

Fine-tuning can be used to slightly retune multiple oscillators and create a chorus-like effect.

What does a synthesiser’s polyphony tell us?

How many notes it can play simultaneously.

A monophonic synthesiser can only play one note at once.

What is the glide/portamento control used to do?

Alter the amount of time it takes to slide between two overlapping notes.

What does changing the synthesiser’s pitch bend range control?

How many semitones the pitch bend wheel or MIDI data will bend a note up or down by

What is the function of the filter on synthesiser’s?

Removes frequencies from the initial signal to shape the sound.

What is a low pass filter?

Removes all the frequencies above the cutoff frequency

What is the cutoff frequency?

The point at which the filter begins to remove frequencies

Some synths also include what other two filters?

High pass filters and band pass filters (covered in EQ topic)

What is resonance in filtering?

Resonance adds a characteristic narrow boost of frequencies around the cutoff on a synth filter

What sort of sound does resonance make?

It accents a small range of frequencies and creates a ‘whistly’ sound that makes the signal close to the cutoff seem brighter and harsher.

What do high resonance settings lead to?

Self-oscillation.

This is where the boost of a specific frequency is so loud, the filter ‘creates’ a pitched note.

What is the amplifier in synthesisers?

This controls the sound’s volume.

Control signals such as envelopes and LFOs can be used to alter the volume over time.

What is the envelope generator in synthesisers?

This can be used to control the oscillator, filter and/or amplifier.

This depends on the specific synthesiser.

What are the 4 envelope stages?

Attack, decay, sustain, release

Explain Attack.

The time taken for the parameter up increase from 0 to the maximum level.

Explain Decay.

The time taken for the parameter to decrease to the sustain level.

Explain Sustain.

The level at which the parameter is held whilst the key remains pressed.

Explain Release.

The time taken for the parameter to decrease to 0, once the key is released.

Graph of the envelope stages.

What parameters can be controlled by an envelope?

Pitch, filter cutoff frequency, volume

What other two things does the envelope also do?

Creates a sound’s timbre, and creates a signal’s harmonic content.

This is part of what helps us to tell a piano apart from a violin.

What does LFO stand for?

Low frequency oscillator

What is the function of LFO?

Like an envelope, LFO is a control signal used to alter a parameter over time.

Most synthesisers can also use LFO to control different modules.

If controlling the oscillator, what can LFO do?

It can change the base pitch generated, creating vibrato.

Diagram of this

If modulating the filter cutoff frequency, what will LFO do?

It will periodically change this according to the LFO wave shape.

What is the rate in LFO?

The speed at which modulation takes place.

This can either be synced to a note value in a DAW or given an absolute value in hertz (often around 0.05Hz and 15Hz.

What is the depth in LFO?

How much the modulation affects the assigned element of the synthesiser.

The greater the depth, the wider the range of values for the modulated parameter.

What is the shape in LFO?

The type of waveform used to modulate the signal (eg sawtooth, square)

What is one of the most useful features of LFOs in a DAW?

The ability to sync the LFO to the main tempo of the project, creating effects that are in time with your track.

What are some historically important synthesisers from the 60s?

Moog modular (1965). Used in Switched-On Bach - Wendy Carlos.

Minimoog (1969). Used in Are Friends Electric? (lead line).

What is a historically important synthesiser from the 70s?

Sequential Circuits Prophet-5 (1977).

Used in Wonderful Christmastime - Paul McCartney and Take On Me - Aha (opening riffs).

What are the four historically important synthesisers from the 80s?

Roland Jupiter-8 (JP-8) (1981)

Do the rest

Do other electronic instruments

What is an arpeggiator in synthesisers?

A basic sequencer that plays or repeats a number of notes in a specific pattern.

What synths were these incorporated into?

Some analogue synthesisers.

Eg the Roland Jupiter 8

What are the benefits of arpeggiators on software synthesisers?

They can be synced to the project tempo, and you can select a note value.

Why are plug-in instruments on computers popular?

Convenience - they have the ability to produce sounds of their hardware equivalent to without having to purchase more than one synth.

Cheaper, and demand - Popular vintage synths are also hard to get hold of, and are often very expensive.

What have synth manufacturers achieved in recent years?

They have developed and released equipment that combines analogue technology and sounds with computer control.

What are the benefits of analogue synthesisers?

Analogue sound is arguably ‘warm’, compared to ‘harsher’ digital sounds. This is because of the ‘flaws’ of analogue technology - things like noise, distortion and tuning drifting.

CV/gate systems can sync analogue equipment together, converters exist to connect analogue synths to MIDI equipment.

More unique, less common sound. As others use the same presets and sounds on software synths.

‘Hands-on’ interface and permanently routed controls on analogue synths are superior to clicking buttons on software synths.

What are the benefits of software synthesisers?

Can be automated, MIDI controlled and easily sequenced.

DAWs allow you to easily sync LFOs/arpeggiators to a note value.

Better signal to noise ratio.

Wide variety of presets available at the touch of a button, convenient

You can create your own presets and share them on the internet, so social aspect.

Stay in tune reliably (it is common for analogue synths to go out of tune when they heat up).

Can have more envelope stages, types of waveform, oscillators and filter types.