Yamaha SY35 Owner's Manual (getting Started) - Page 45

LFO MIDI Modulation Multi Pan Preset Vector 42 LFO stands for "Low Frequency Oscillator." This is the oscillator, usually with a frequency variable from about 0.1 to 20 hertz, that is responsible for creating the periodic variation in tremolo, vibrato, chorus, phasing, and other modulation type effects. "MIDI" is an acronym standing for "Musical Instrument Digital Interface." MIDI allows musical instruments, sequencers, signal processing devices, computers, and other devices to communicate and control each other via a simple cable connection. The introduction of MIDI has revolutionized the music field, making control of the music production process easier and more efficient than ever before. In synthesizers, the term "modulation" usually means to vary the amplitude or frequency of a sound in accordance with some other signal. This "other signal" is most commonly the output from the synthesizer's LFO (described above), although in Yamaha FM synthesis (also see above) it can also be the signal from a modulator operator in an FM algorithm. Although normally a prefix, as in "multi-talented," the term "multi" on its own has come to refer to multi-timbre setups in the synthesizer world. A multi is usually a group of 8 or 16 voices that can be played simultaneously either from the instrument's keyboard, sometimes in split-keyboard configurations, or via MIDI. For MIDI control each voice receives on a different MIDI channel number, allowing multi to be handled as multiple tone generators by the controlling sequencer or computer. Multis also allow a number of parameters to be programmed individually for each voice: volume, pitch, effects, etc. The word "pan" is derived from the "pan pot" controls found on mixing consoles, which is in turn derived from "panoramic potentiometer." A pan control or parameter determines the position of a specific sound - e.g. an element of a voice or a drum instrument - within the output stereo sound field. Panning to the left means that more of the corresponding sound is delivered via the left channel than the right channel, and vice versa. The listener then hears the sound at the appropriate position between the stereo speakers or headphones. A "preset" can be any unit of data - a voice or multi (see above), for example - that is pre-programmed by the manufacturer and provided with a synthesizer. Presets make life easier for beginning synthesizer users as well as performance-oriented players who simply want to select a sound and play without having to do any programming of their own. The quality of the presets included with an instrument is therefore critical to the value of the instrument. Mathematically speaking, a "vector" is a physical quantity with both magnitude and direction. This applies in a similar way to vector synthesis in that the vector control controls the magnitude and direction of a quantity that can be pitch or level.