The appearance of FM (Frequency Modulation) sound generation was a major turning point in the history of synthesizers. Its metallic and sharp sounds, most notably electric piano and synth bass, have been loved by all music creators since 1980 up to the present time. The volca fm perfectly reproduces the sound engine of the classic digital synthesizer that made the world aware of FM synthesis. Its six operators and 32 algorithms provide complete compatibility, and it can even load files in the SYS-EX/SYX format of the Yamaha DX7.
In the second case we just add together the two simple FM spectra, but in the first case we get a more complex mixture involving all the sums and differences of the modulating frequencies. These sum and difference tones ("intermodulation products") are not limited to FM. Anynonlinear synthesis technique produces them. Being non-linear, it must have something that involvesa power of its input other than 0 or 1; if we feed in sin a + sin b, for example, that term will producenot just (sin a)^n and (sin b)^n, but all sorts of stuff involving sin a * sin b (in various powers),and this produces things like cos(a+b) and cos(a-b).For a less impressionistic derivation of the spectrum, see Le Brun,"A Derivation of the Spectrum of FM with a Complex Modulating Wave". The result can be expressed:
ADSR envelopes are often used to control the volume of a sound, although they can be used to control almost anything inside a modular synthesizer. For example, the same envelope could control a resonant low pass filter, making a cool sweeping and wooshing effect evolve as we play each note.
Envelopes like the one pictured here are called , so named for their four stages: and . When we put an ADSR envelope module in a synthesizer, we specify exactly what is to happen during each stage of the envelope after an "on" gate signal is received. For example, the envelope pictured above has an attack stage that lasts 250 milliseconds, where the level increases to 1. After that, it has a decay stage lasting 200 milliseconds where the level decreases to 0.7. During the sustain stage, the level stays at 0.7 for as long as the envelope generator is receiving an "on" gate signal. Sustain stages do not have a specified duration. When the gate signal changes to "off," we enter the release stage, where the level takes 200 milliseconds to drop to 0.
- Ableton Live has it's own…frequency modulation capable synth,…aptly named Operator.…In this movie we'll see how we can use…FM synthesis to program some tones on Operator.…The first thing you'll notice with Operator…is that there are four possible oscillators…to choose from.…Oscillator A, B, C, and D.…These are, by default, wired in series…so that oscillator A is modulated by oscillator B.…Oscillator B is modulated by C,…and oscillator C is modulated by oscillator D.…
The text of this article is accompanied by illustrations, audio examples, and links to working demonstrations in . PureData is a powerful, free, cross-platform, open source music synthesis tool. It's a good idea to read this article with PureData open in the background, building and learning as you go.
This article is a (relatively) brief introduction to the principles of music synthesis. Each of the basic components of synthesizers are explained, along with descriptions and examples of how these components are chained together to make interesting sounds. The principles discussed are not unique to any specific synthesis platform, but are applicable to music synthesis in general.
Modulation means using one signal to affect another signal. A simple example of Frequency Modulation synthesis (FM) consists of one oscillator (the MODULATOR), modulating the frequency of another oscillator (the CARRIER). This procedure produces additional frequencies called SIDEBANDS which form symmetrically around the original frequency of the CARRIER. For example, here is a simple FM patch:
Using you will apply FM synthesis techniques to create the effect of the 9 partials of the Bell using only 2 operators: the carrier operator and the modulator operator. The sideband frequencies which are produced in the FM patch are the equivalent of the partials in the Additive Synthesis Bell. Here is the SYD patch for a simple FM bell patch
Another type of module frequently used to control other modules is the , or . An LFO is just like a normal oscillator, it can have any waveform and amplitude we specify, but it has a very low, sub-audio frequency, producing a very slowly oscillating signal generally used to control other modules within a synthesizer. For example, an LFO might move the volume level of a VCA up and down, creating a tremolo effect. LFOs are like little robots that turn knobs back and forth for you.