The DRUM! Glossary Of Electronic Percussion
VIRTUAL INSTRUMENTS: Virtual instruments are software versions of synthesizers. Rather than being physical, they are recreated inside software. Many virtual instruments were designed to replicate well-known physical machines. Others offer features and flexibility that simply wouldn’t be possible on a “real” instrument. Virtual instruments can run as free-standing applications or as plug-ins for DAWs.
OSCILLATOR: On any type of synthesizer, the oscillator is the first step to sound creation. Once a sound is produced by the oscillator, other components of the synthesizer are used to further shape and modify the tone. Oscillators may create musical wave shapes (such as sine wave, square wave, or triangle wave) or play sampled sounds.
SAMPLES: Samples are nothing more than digital recordings of sounds. A sample can be a single snare drum hit, a trombone glissando, or a looped drum groove. Depending on the ability of your synthesizer, you might be able to play different samples based on your stroke strength. This is an example of multisampling.
MULTISAMPLING: For nearly all acoustic instruments, playing soft or playing loud changes much more than just the volume. The quality of the attack, the exact tone of the sound, and the speed and character of the decay are all affected by the playing dynamic. When an instrument is multisampled, the performer’s playing velocity can determine which digital recording will correspond to certain dynamics. Two common ways to achieve this are velocity switch and velocity fade.
VELOCITY SWITCH: A velocity switch would occur when, for example, MIDI volumes of 1–44 play one sample, and velocities of 45–127 play a second sample. Depending on the flexibility of your hardware or software, you may be able to program dozens of different velocity switches.
VELOCITY CROSSFADE: A velocity crossfade occurs when a more gradual change occurs between samples. For example, as you play stronger and stronger, one sample would fade out while another sample fades in. Sounds can fade out completely or fade further into the background. Again, it might be possible to arrange dozens of velocity crossfades within a multisample.
LFO: An LFO is an acronym for a Low Frequency Oscillator. LFOs are often used in electronic instruments to provide vibrato, movement between stereo positions, and changes in tone color. LFOs provide a fluctuation in a sound in order to make it appear more natural or more unique.
ENVELOPES: An envelope in electronic music is not something to hold a letter, but something to hold a sound. In order to describe an envelope, it might be a good idea to think of the volume of a sound over time. A wood block has a very quick and loud attack that decays over a very short time. A cymbal struck with a soft mallet has a slower attack than the woodblock, yet has a much longer decay over time. In electronic music terms, these two instruments have a different envelope.
ADSR: The ADSR envelope is the most basic in electronic music. It is another acronym for Attack, Decay, Sustain, Release. The attach portion of the envelope is a value of how quickly the sound begins. The decay portion is the way a sound might change right after the initial attack. The sustain part is how long (and usually how loud) the sound is sustained — think about the sound of an organ or a long tone on a trumpet. The release is a value of how quickly a sound dies out after the gate time is reached.