Yamaha DX7 Product Manual - Page 28

HOW THE DX7 CREATES SOUNDS Breath Controller or Foot Controller) to turn notes up and down within the existing envelopes, provided you are also playing the notes on the keyboard. The more EG bias, the less amplitude is present when you play a note; the level increases when you add EG bias by advancing the Wheel. 7. When you've experimented with [MODULATION WHEEL-EG BIAS], turn it OFF, and try each of the 3 types of modulation with the other sources (Foot Control, Breath control and After Touch). Each of the above sources of modulation can be pro- grammed to function differently, so this is not neces- sarily a redundant system. For example, you might use the after touch to add pitch modulation, the modulation wheel to add amplitude modulation, and the breath controller to alter EG bias (blowing notes, provided you first hold down the key(s)) for a given voice. 8. After you've explored all the modulation functions, we recommend that you go through them and set them in a way that will be useful as you work through other sections of this manual. Therefore, please set the modulation as follows: CONTROLLER RANGE FUNCTION PITCH AMPLITUDE EG BIAS MODULATION WHEEL 50 ON OFF OFF FOOT CONTROL 51) ON OFF OFF BREATH CONTROL 50 ON OFF OFF AFTER TOUCH 50 ON OFF OFF (These settings are not ideal for all voices. If, for instance. you're playing the voice called "SAX - BC1", you will want to turn ON the Breath Controller EG bias, and perhaps set Us range to 99.) Operators The Yamaha DX Series FM digital synthesizers use pure tones (sine waves) that interact to create all the overtones needed for any voice. Each sine wave oscillator has its own envelope generator. The combination of the two is called an "operator." The primary functional circuit in the DX7 is comprised of the digital SINE WAVE OSCILLATOR plus a digital ENVELOPE GENERATOR with multiple inputs and just one output. This is called an OPERATOR. If you could look inside an operator (which is just a digital circuit), you might see a block structure that looks like this: When the output of one OPERATOR is "patched" to the input of another Operator, the result is a complex waveform. This is the essence of FM SYNTHESIS. Carriers, Modulators and FM The DX7 has 6 operators. When the output of one operator is connected to the input of another, modulation occurs. Harmonics are generated - up to a whole spectrum of frequencies that are the equivalent of a triangle wave or a sawtooth or a square wave, etc. - all from a pair of sine waves. Additionally, operator's sine wave outputs can be mixed together. The two processes, mixing and modulating (whereby the sine waves interact and produce complex sounds), are called FM synthesis.