Yamaha DX27 EN User Manual
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effects can be applied to the selected operators. A setting of 7 produces maximum
sensitivity and therefore maximum effect depth.
12: KEY VELOCITY
While the DX27 has no key velocity sensitivity of its own, its voice generators will
accept key velocity data from an external MIDI controller keyboard which does
have this feature. This function determines the sensitivity of each operator to
keyboard velocity sensitivity data from an external keyboard connected to the DX27
MIDI IN terminal (key velocity sensitivity = the harder you play a key, the louder
the note. Timbre variations are produced when keyboard sensitivity is applied to
a modulator).
The data range is from 0 to 7. At 0, key velocity sensitivity for the selected operator
is OFF. A setting of 7 produces the highest sensitivity, and therefore the greatest
effect. If KEY VELOCITY is set to other than 0, the volume produced when DX27
keys are pressed will decrease.
13: FREQUENCY RATIO
These parameters determine the actual frequency of each operator. For operators
which function as carriers, this determines the actual pitch of the sound produced.
For operators functioning as modulators, this determines the harmonic spectrum
of the sound produced.
Each operator can be set to any of 64 different frequency ratios, as follows:
DX27 OPERATOR FREQUENCY RATIOS
0.50
0.71
0.78
0.87
1.00
1.41
1.57
1.73
2.00
2.82
3.00
3.14
3.46
4.00
4.24
4.71
5.00
5.19
5.65
6.00
6.28
6.92
7.00
7.07
7.85
8.00
8.48
8.65
9.00
9.42
9.89
10.00
10.38
10.99
11.00
11.30
12.00
12.11
12.56
12.72
13.00
13.84
14.00
14.10
14.13
15.00
15.55
15.57
15.70
16.96
17.27
17.30
18.37
18.84
19.03
19.78
20.41
20.76
21.20
21.98
22.49
23.55
24.22
25.95
These frequency ratios have been carefully chosen as the most useful for voice
programming. A ratio of 1.00 sets the selected operator to standard pitch—a pitch
of 440 Hz will be produced when the A3 (A above middle C) key is pressed. A
ratio of 0.50 produces a pitch one octave lower, and a ratio of 2.00 produces a
pitch one octave higher than standard pitch, and so on. The fractional ratios-1.73,
for example—produce extremely complex waveforms when combined with operators
set to other ratios, permitting the creation of an unlimited variety of sound effects
including extremely realistic bells, explosions, etc. Even ratios are useful for creating
musical instrument sounds. It is possible to combine a modulator set to a fractional
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