Electronic Music Interactive, 2nd edition

Glossary

daisy chain: a type of configuration for a MIDI system where MIDI data is transmitted from one instrument to the next, to the next, and so on.
data byte: one of two types of bytes in the MIDI protocol. Data bytes have numerical values ranging from 0 to 127 and specify additional information about what is to be done and often come in pairs. Data bytes are always preceded by a status byte and are identifiable because their first bit is always "0".
decay: the second stage of a four-stage envelope, but may have other meanings depending on context.
destructive interference: when the amplitude of one wave or frequency combines with the amplitude of one or more waves or frequencies to create a decrease in amplitude.
digital recording, digital sample: a generator module in the synthesis process which outputs a sound that has been previously recorded.
digital recording: a way of documenting the fluctuating voltages of an analog signal over time by taking measurements of the instantaneous amplitudes in the analog signal at equally spaced time intervals. The measurements of the amplitude are usually thousands of times per second with 44,100 times per second being a standard rate.
digital sampling: the process of converting an analog representation of sound to a digital representation of sound by taking measurements of the instantaneous amplitudes at equally spaced time intervals. These amplitude measurements are usually taken thousands of times per second.
digital synthesizer: an instrument that produces digital representations of sound, which the user may design. Presumably these "synthesized" sounds will be subsequently converted to an analog signal, and then to acoustic energy so that we may hear them.
digital to analog converter (D/A converter, also DAC): a device which takes the series of stored numbers, the digital representation of sound, and changes it back to an analog signal.
duty cycle: in describing square and rectangle waves, the percentage of the waveform that occurs above the zero axis. A square wave always has a 50% duty cycle, while rectangle waves have a duty cycle other than 50%.
electroacoustic transducer (transducer): a transducer is a device that converts one type of energy to another type of energy.
electronic music: used to refer to any type of music composed with any electronic instrument or device and that are played back through loudspeakers. "Electro-acoustic music" is often used to mean the same thing. In some instances, electronic music is used to describe a particular class of "electro-acoustic music" that does not use any prerecorded or sampled material.
envelope: the non-periodic, time-variant shape output by an envelope generator.
envelope generator: a time-variant controller that outputs a non-periodic, time-variant control signal which induces changes in other synthesis modules. The shape of the output control signal is called the envelope, and can be defined by specifying times and levels in each of the envelope stages.