Yamaha DX7 Product Manual - Page 64

DX SYNTHESIZER GLOSSARY ADSR This is an acronym for "Attack-Decay-Sustain-Release" Break point In the DX7, the operator output level and in the DX synthsizers may also be programmed to have 59 which, in turn, refers to the four controls provided on a con- the envelope rates may be scaled to increase or decrease delay in that it may not begin sounding the note until ventional synthesizer's envelope generators. While the DX synlhesizers can simulate ADSR-type EGs, the DX EGs are more complex. ADSR EGs have 4 variables, whereas DX EGs have 8 variables. as notes are played across the keyboard. With the key- some time after the key is depressed (this is a different board level scaling in particular, almost any note may be type of delay than the modulation delay). In a broader chosen as the starting point for a boost or cut curve to sense, delay may describe a signal processing effect either side. This starting point is knon as the "break which is used to produce echo (i.e., analog delay or After Touch The DX7 keyboard has pressure transduc- point." The break point for keyboard rate scaling is not digital delay units). ers beneath the keys that permit the player to alter the sound based on how hard the key is pressed after it "bottoms out." This aspect of touch sensitivity is known as After Touch. It may be used to apply LFO modulation to the pitch or amplitude, or to alter the envelope generator bias, depending on the way the DX7 FUNCTION mode is programmed, and depending on the programmed values within the particular voice. Algorithm An algorithm is an arrangement of operators. It is roughly the equivalent of a "patch" in an older style, modular synthesizer. The DX7 has 32 different algorithms. adjustable, and falls below the lowest note on the keyboard. Carrier When an operator is at the bottom of a stack within an algorithm, where it contributes directly to the output of the synthesizer, it is considered to be a carrier. There is no difference between a carrier and a modulator in that both are operators; their relative arrangement within the algorithm is what differentiates the two. Cartridge In the DX7, there are two types of nonvolatile voice storage. One way to store a voice is on the internal memory, which, while it is electronic, is not erased when power is turned off due to an internal EDIT mode This mode permits you to program individual parameters of a voice (such as the envelope, operator frequency, keyboard scaling, and so forth). EDIT mode may be entered by pressing [EDIT/COMPARE]. EEPROM This is an acronym for "Electrically Erase able, Programmable, Read Only Memory" The RAM cartridges contain EEPROMs which store the voice data. There are no moving parts nor any batteries in an EEPROM; the data is stored by means of an electric current that "burns a pattern" in the memory, and erased by a different electric current, both of which arc supplied by the DX7. AMD This is an abbreviation for "Amplitude Modulation Depth." Increasing the AMD value applies more LFO modulation to the operators, which causes their output levels to go up and down according to the set LFO speed and waveform. AMD will have an effect only if the Amplitude Modulation Sensitivity is set higher than 0 for individual operators. battery. The other voice storage medium is the cartridge. There are two types of cartridges, RAM and ROM (see these definitions). Cartridge Form This is an abbreviation for cartridge format. Formatting a RAM cartridge on the DX7 erases all voices and instead sets the 32 memory locations to the "initialized voice" (see INIT). ROM cartridges cannot EG This is an abbreviation for "Envelope Generator" An envelope generator is the circuit which creates the "shape" of a note - the rates at which it turns on and dies away and the intermediate levels. The DX7 has 6 primary EGs, one to shape the output level of each operator, plus another EG which changes the pitch of all 6 operators. Amplitude This refers to the output level of an operator. Amplitude may or may not be related to "volume," depending on whether the operator whose amplitude is being varied is a modulator or a carrier. When the amplitude of a carrier is changed, the "volume" or output level of the synthesizer changes. When the modulator amplitude is varied, the timbre of the voice changes, and, subjectively, the volume may also change (loudness depends on timbre as well as level). Attack This is the beginning of a sound or the initial be formatted. CRT In the DX7, CRT is an abbreviation for "cartridge." (In most other situations, CRT stands for "Cathode Ray Tube," Current operator In the EDIT mode, this is the operator whose parameters are displayed, and which you can program with the DATA ENTRY controls. Even when several operators are turned ON, you can only adjust or examine one at a time, the "current operator." Envelope This is the overall "shape" of a note in terms of its output level. When you play a note. typically the sound rises to some level, then falls to another level, and, when you release the key, falls to zero level - although there are many exceptions. The specific rates at which the levels change, and the intermediate and final levels, together define the envelope. In the DX7, envelopes may apply to carriers (which change the volume of the sound), to modulators (which change the timbre) or to the pitch (which changes the frequency of transient of a musical note. In the DX synthesizer enve- Decay In a typical musical note, the initial fading of the note). Envelopes are programmed with the EG lopes, L1 generally determines the maximum level of sound after the attack. (envelope generator). the attack, while Rl determines how rapidly the note reaches L1. Rl can thus be considered the attack rate. In a conventional synthesizer, there is no attack level (L1); it is always at maximum (equal to 99 on the DX), and the attack time is adjustable. The DX envelope's attack time is indirectly set by the attack rate since, if the level is made higher at a given rate, it will take more time to reach that level. If L1 and L2 are zero, however, then R3 and L3 determine the attack time and level, while R2 sets the turn-on delay; Rl should be at 99. Default The "default" values for programmed parameters are the values which the synthesizer automatically selects if not otherwise programmed. This primarily applies to the initialized voice or the cartridge format voices. Delay In the DX synthesizers, it is possible to program a voice so that its built-in LFO modulation does not begin as soon as you play a note, but after a certain time. That time span is known as "delay," An envelope Feedback In general, feedback is the return of the output from a circuit to the circuit's input. The DX7 allows for feedback from the output of an operator back to its input, or to the input of an operator higher up in the same "stack" of the algorithm. All 32 algorithms have feedback paths, but there is feedback only if the voice is so programmed. Feedback may be set to any of 8 levels from 0 (no feedback) to 7 (maximum). The effect of feedback is similar to the use of an additional modulator, though not precisely the same.