Yamaha DX7 Product Manual - Page 48

The display should look like this. Play several brief

notes

10. Now use [DATA ENTRY] to turn the sync OFF

Again, play the same brief note several times, and

listen to the pitch each time. You'll hear the initial

pitch of each note change slightly as the randomly

timed notes interact with the regularly oscillating

LFO. With less exaggerated settings, leaving the LFO

Sync OFF will cause minor changes from note to

note that result in a more natural simulation of an

acoustic instrument.

Then adjust

[DATA ENTRY] so

the display looks like

this, and again play several brief notes

The two amplitude modulation functions, LFO [AMD]

and [MOD SENSITIVITY-AMPLITUDE], work similarly

to the pitch modulation depth and sensitivity, except that

the amplitude sensitivity can be programmed separately

for each operator. The SAX-BC1 voice in the Master

Group is a good example of the use of LFO amplitude

modulation, where the breath controller can be used to

change the level of several operators.

To see how the amplitude modulation works, lets turn

off the pitch modulation temporarily and turn on the

amplitude modulation.

11. Turn LFO Sync ON again by pressing [SYNC] and

the [ON] button. Then set the pitch modulation

depth at 0 by pressing [PMD] and pulling down the

[DATA ENTRY] slider.

12. Press [AMD] and bring the amplitude modulation

depth up to a high value (from 50 to 99), and play a

note on the upper section of the keyboard. (Remem-

ber that the Keyboard Level Scaling has "rolled off"

this sound on the lower part of the keyboard). Notice

there is no amplitude modulation yet. You need to

"open the gate" for each operator that you want the

modulation to affect.

And adjust the

[DATA ENTRY]

controls to see this

13. Press [MOD SENSITIVITY-AMPLITUDE] and then

press [OPERATOR SELECT] to set Operator 2 as

the current operator. Then use [DATA ENTRY] to

bring up the sensitivity to a maximum of 3. Play a

note, and listen to the timbre change. This modula-

tion will be very pronounced, so you'll probably

want to lower the sensitivity to about 1. The timbre

changes because the LFO is modulating the modula-

tor which produces the harmonics.

And the display should look like this

to select OP2, and adjust

[DATA ENTRY]

to 3 first, then

to 1

Now lets see what happens when you modulate the

carrier's level.

14. Press [OPERATOR SELECT] as needed to select

operator 1, and then adjust its amplitude sensitivity

to the maximum (3). Play a note in the upper part of

the keyboard, and hear the wide deviations in vol-

ume. The wide deviations in volume occur because

the LFO is being applied to change the output level

of the carrier through which

all the sound in the

stack must travel.

Now reduce the sensitivity to 1.

and

adjust

[DATA ENTRY] to

maximum (3) then (1)

15. The amount of amplitude modulation is probably

still much too high, but we may want some ampli-

tude modulation SENSITIVITY for use by an external

modulation source (like the wheel or breath control-

ler). Therefore, leave the sensitivity settings alone.

Instead, press [AMD] and use [DATA ENTRY] to

bring the amplitude modulation depth down to

about 10 (very little depth compared to the maxi-

mum

of

99).

And adjust the

[DATA ENTRY]

controls to see this

16. Add some pitch modulation depth (it should be at

zero) to obtain a pleasing frequency variation for

some interest. Press [PMD] and set it to 15. Then

press [DELAY] and set it to 55, press [SYNC] and

turn off the key sync, and press [SPEED] and reset

it

to 27.

Now reset all these

parameters for a

more natural

sound

43

Yamaha DX7 Product Manual - Page 48

Turn LFO Sync ON again by pressing [SYNC]

Page 48 highlights