Yamaha Vintage DX7 Special Edition ROM Operation Manual Download

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"live" after you exit the FUNCTION mode by pressing

one of the [MEMORY SELECT] buttons (internal or

cartridge). The [DATA ENTRY] controls only change

the last used parameter prior to pressing the [MEM-
ORY SELECT] button. This feature can be useful as an
additional live performance control. For example, you

might go into the EDIT mode and select [LFO

SPEED]. Then go back to the PLAY mode and you can
play any voice you like and change its LFO speed by

moving the [DATA ENTRY] controls. Similarly, you can

go into FUNCTION mode and adjust [MASTER

TUNE], then go back into PLAY mode and use [DATA

ENTRY] to tune a voice. One application of this charac-

teristic is to achieve simulated "doppler shift" with the

train bell or whisltle (Doppler effect is the increase in
pitch that occurs as two objects move closer togther at a
rapid rate, and the decrease in pitch as they move
apart).

One of the most important parameters to access dur-

ing performance is the POLY/MONO mode selection.

You can exit FUNCTION mode after first pressing
[POLY/MONO], and then toggle between these modes

while playing various voices.

The ability to change the last selected FUNCTION

parameter is particularly useful for changing the

portamento characteristics. For example, you can enter

FUNCTION mode and adjust the [PORTAMENTO

TIME], then play a voice and alter that time as you play.

A very useful "trick" relies upon the difference in por-

tamento that occurs between polyphonic and mono

modes. As explained here, you can use [DATA

ENTRY] to switch between fingered portamento with a

mono keyboard (useful for a Fretless Bass voice), and no

portamento with a polyphonic voice (Electric Piano, for

example).

1. Wire a standard phone jack so its tip is shorted out to

its sleeeve (jumper from tip to sleeve). Insert this plug

in the Portamento Foot Switch jack on the back of the
DX7. It has the same effect as though you plugged in

a foot switch but did not step on it.

2. Enter FUNCTION mode. press [POLY/MONO], and

set the instrument for MONO operation.

3 Press [PORTAMENTO MODE] and select "FIN-

GERED PORTA". You'll notice that fingered porta-
mento is not sensitive to the portamento foot switch,
so it will work even though the shorted jack is

present.

4. Press [POLY/MONO] again before leaving FUNC-

TION mode so that the [DATA ENTRY] slider or

[ON] and [OFF] buttons will toggle the keyboard

between polyphonic and mono operation.

5. Press [MEMORY SELECT] (internal or cartridge) to

enter the PLAY mode.

When you select a voice like the Fretless Bass, push

up [DATA ENTRY] or press [>] to set the DX7 to

MONO mode. You can now use fingered portamento
(holding one key while pressing and releasing
another) to achieve a pitch bending glide to the next

note, or play notes sequentially to avoid portamento.

If you select another voice, such as Electric Piano, pull

down [DATA ENTRY] or press [<] to return to poly-
phonic operation; since the portamento jack is
shorted, there will be no portamento on that voice. If
you want, you can use a foot switch in the Porta-
mento jack, in which case the portamento would be
active in POLY mode when you step on the pedal.

If you don't want to accidentally have a parameter

change whenever you're in PLAY mode, select a non-

critical parameter before you exit the FUNCTION
mode. From FUNCTION mode, for example, you

might press [BATT CHECK] before going into PLAY
mode. This will avoid accidental, unexplained

changes while you are playing.

Reference Sources on FM Synthesis

FM digital synthesis, of the type used in the DX syn-

thesizers, was pioneered by Dr. John M. Chowning and

his associates at Stanford University in the early 1970's.
A number of research papers have been published, and
offer the technically-inclined reader ample opportunity
to understand the theory and mathematics of FM syn-

thesis.

John M. Chowning, "The Synthesis of Complex Audio
Spectra by Means of Frequency Modulation," Journal
of the Audio Engineering Society Vol. 21,

7 pp 526-

534 (Sept. 1973); reprinted in Computer Music Jour-

nal, Vol. 1,

1, pp 46-54 (April 1977).

John Grey, "An Exploration of Musical Timbre," PhD

Dissertation, Dept. of Psychology Stanford University

(Feb. 1975); distributed through the Dept. Music, Tech.

Rep. Stan-M2.

James A. Moorer, "The Synthesis of Complex Audio

Spectra by Means of Discrete Summation Formulas,"