Fm In Brief - Yamaha FS1R Owner's Manual

FM In Brief

Briefly, FM synthesis is based on arranging operators — individual oscillators which can function as both modulators
and carriers — in "algorithms" capable of producing the desired sound. the most simple algorithm (algorithm 1 in
the FS1R) simply add the output of all 8 operators together, with no modulator-carrier relationships. This algorithm is
ideal for synthesizing simple "additive" sounds — like some organ voices, for example.
Much more complex harmonic spectra can be produced by using algorithms in which one or more operators
function as modulators, modulation the output of their respective carrier operators. In algorithm 6, for example,
operator 1 modulates operator 2, operator 3 modulates operator 4, and operators 5 through 8 are unmodulated.
Algorithm 2, on the other hand, includes a modulator "stack" in which operator 1 modulates operator 2, which in turn
modulates operator 3, which in turn modulates operator 4.
Note that in all three algorithms introduced above, operator 1 includes a feedback loop which allows a specified
portion of the operator's output to be fed back to its own input for even greater timbral complexity. Since each
operator has its own amplitude EG, a virtually unlimited spectrum of responsive, musical voices can be produced.
FM Synthesis Parameters
The following parameter groups and parameters are essential for basic FM synthesis. Refer to the parameter
descriptions for details:
• EDIT [VOICE] mode COMMON/Others/...................................................Page 58
• EDIT [VOICE] mode OPERATOR/Osc/.....................................................Page 62
• EDIT [VOICE] mode OPERATOR/EG/ ......................................................Page 66
• EDIT [VOICE] mode OPERATOR/Sns/ .....................................................Page 68
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