Yamaha DX7 II FD Reference Manual page 10

De tune
In
fixed mode, the coarse and fine parameters specify the frequency of the operator in
Hertz (Hz). In ratio mode, the frequency of the operator depends on the key being played.
The coarse and fine parameters specify the interval between the operator and the standard
pitch associated with each key. For example, setting the coarse and fine parameters to a
value of 2.00 in ratio mode will cause the operator to sound one octave higher than the
standard pitch level of the keyboard. A setting of 0.50 causes the operator to sound one
octave lower than standard pitch.
Fixed mode values (in
Hz)
1.
OOOHz
Lowest fixed mode value.
1000
Hz
Highest coarse value
9
7 7
2
Hz
Highest fixed mode value.
Ratio mode values
0 . 50 Operator sounds one octave below standard pitch.
1 . 0 0 Operator sounds at standard pitch.
2. 00 Operator sounds one octave above standard pitch.
31.00 Highest coarse value (nearly 5 octaves above standard pitch).
61. 69 Highest ration mode value (nearly 6 octaves above standard pitch}.
Remember that doubling the coarse and fine parameter values raises the pitch of the
operator by one octave. In ratio mode, octaves below and above the standard pitch are
obtained at values of 0.50, 1.00, 2.00, 4.00, 8.00, and so on. The ratio value forming a
fifth with the standard pitch is obtained at 1.50 and the ratio value forming a third with the
standard pitch is obtained at 1.25.
The detune parameter provides a "super fine" frequency control for each operator. It is
used to shift the frequency of an operator by as much as 2 cents up or down (1 cent
=
1/lOOth of a semitone). This parameter is independent of the coarse and fine parameters.
- 7 Shift operator frequency down 2 cents.
0 Do not shift operator frequency.
+
7 Shift operator frequency up 2 cents.
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