FM and Ring Modulation Flashcards
Define FM synthesis ?
Modulating the pitch of an oscilator with another oscillator that is producing a frequency in the audible range
What are the two most important parameters when utilising FM synthesis ?
The frequency of the modulator oscillator and the range (depth/amount) of the frequency modulation on the carrier oscillator.
How would you set up adjustable frequency modulation (in Reaktor/modular environment) if there was no dedicated FM input and control on the oscillator ?
You would route a modulator oscillator through a VCA and the VCA output into the modulation input of the carrier OSC, then you would increase the pitch modulation amount for that modulation input and use the level (output/amplitude) of the VCA to increase/control the modulation amount
In Reaktor’s Bento Box Oscillator what are the three modes for FM synthesis ?
Linear, Exponential and Linear through zero (LTZ)
In Reaktor’s Bento Box Oscillator which FM mode should you use for making ‘musical’ patches (i.e. bass, lead etc. rather than FX) and why ?
LTZ (Linear through zero) mode should be selected for more musical patches as it will retain the fundamental pitch being played and only adds harmonic frequencies above the fundamental (partials) and no inharmonic frequencies
In FM synthesis what determines the amount and amplitude of sidebands in the carrier signal ?
The amplitude of modulation being applied by the modulator oscillator to the pitch (frequency) of the carrier oscilator
If using an oscillator/synth that is not dedicated to FM synthesis what two things would need to be set/selected in order to create hamonic sidebands for a musical sound?
Both the carrier and modulator oscilators need to be set to pitch-tracking and the modulator frequency needs to be set to an integer ratio of the fundamental of the carrier’s pitch (i.e. 2:1, 3:1, 4:1 etc)
In order to create hamonic sidebands in FM synthesis when Ratios are not available in the synth, name the amount of semitones you would need to set the pitch of the modulator oscilator above the pitch of the carrier oscilator in order to achieve the following four integer ratios:
2:1, 3:1, 4:1, 5:1
2: 1 = +12 semitones (one octave)
3: 1 = +19 semitones (one octave plus perfect fifth)
4: 1 = +24 semitones (two octaves)
5: 1 = +28 semitones (two octaves plus major third)
How do you add a Multiply primary module in Reaktor ?
Right click on the background in structure view and select Maths, and then Multiply
How would you setup basic Ring Modulation with two oscillators in Reaktor ?
In the structure view, add two oscilators. Then add a Multiply primary module and connect the outputs of the oscilators to the inputs of the multiply module and connect it’s output to the input of a VCA/mixer etc.
In order to create musical, tonal sounds with Ring Modulation what two interval types should the oscilators be seperated by ?
Combinations of perfect fifths and octaves
When utilising Ring Modulation what two ways of modulating the sound create evolving musical tones ?
Modulating the waveshapeof one of the oscilators (e.g. saw to square) and the interval between the two oscilators (e.g. between a fifth apart and an octave apart)
What is the most basic way to use the FM input on a filter and what is the benefit of doing so?
If a filter has a dedicated FM input it can be used to control the filter cutoff frequency, leaving the other modulation inputs on the filter available for use - with LFOs or the Modhweel for example
