A synthesizer is an electronic musical instrument designed to produce electronically generated sound. Synthesizers create sounds through direct manipulation of electrical voltages, mathematical manipulation of discrete values using computers, or by a combination of both methods. Synthesizers typically have a keyboard which provides the human interface to the instrument and are often thought of as keyboard instruments. However, a synthesizer's human interface does not necessarily have to be a keyboard, nor does a synthesizer strictly need to be playable by a human.
An oscillator is an electronic circuit that produces a repetitive electronic signal, often a sine wave or a square wave.
Low frequency oscillation, often abbreviated to LFO, is a term that predominantly refers to an audio technique specifically used in the production of electronic music. In addition to the main oscillator(s) of a synthesizer, which is responsible for the creation of the audio signal itself, an LFO is an additional oscillator that operates at a comparatively lower frequency (hence its name) that modulates the audio signal, thus causing a difference to be heard in the signal without the actual introduction of another sound source. Most synths in Fruity Loops provide a LFO that can be adjusted to your liking. A low frequency oscillator can be routed to control a variety of different parameters, for example the frequency of the audio oscillator, the phase, panning, filter frequency, or the velocity of the synthesizer's output. For instance, when routed to pitch, an LFO serves to simulate vibrato, and when an LFO modulates amplitude (volume), it creates tremolo. On most synthesizers and sound modules, there are several different ways in which the user can alter the effect produced by the LFO. These may include a variety of different waveforms, a rate control, routing options, a tempo sync feature, and an option to control the amount by which the LFO will modulate the audio signal. Electronic musicians use LFO for a variety of applications, ranging from adding simple vibrato or tremolo to a melody, to more complex applications such as triggering gate envelopes.
* Attack time is the time taken for initial run-up of the sound level from nil to 100%.
* Decay time is the time taken for the subsequent run down from 100% to the designated Sustain level.
* Sustain level, the third stage, is the steady volume produced when a key is held down.
* Release time is the time taken for the sound to decay from the Sustain level to nil when the key is released. If a key is released during the Attack or Decay stage, the Sustain phase is usually skipped. Similarly, a Sustain level of zero will produce a more-or-less piano-like (or percussive) envelope, with no continuous steady level, even when a key is held. Exponential rates are commonly used because they closely model real physical vibrations, which usually rise or decay exponentially.
Although the oscillations in real instruments also change frequency, most instruments can be modeled well without this refinement. This refinement is necessary to generate a vibrato.
Fruity Loops - FL Studio - REsource
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