
PX7 FM SYNTHESIZER
7
Algorithm
An algorithm is basically an operator connection diagram which defines how the six sinewave oscillators are
interconnected. An operator can either be connected and used as a sound generator (carrier) or as a modulator. In
PX7 a carrier is shown with a filled background and a modulator is shown with a dark background with a frame. The
carriers are always routed directly to the Output in the diagrams. The picture below shows the connection principle in
algorithm 22 as an example:
Connections in algorithm 22
The PX7 features the same 32 algorithms as the original classic Japanese FM synth. Below are diagrams of the 32
different algorithms in PX7:
D Select the desired Algorithm by clicking the up/down buttons.
A diagram of the selected algorithm is displayed above the Algorithm selector.
Operators 1, 3, 4 and 5 are carriers (as indicated
by their filled backgrounds). They are connected
straight to the audio Output.
Operators 2 and 6 are modulators.
Operator 2 frequency modulates Operator 1.
Operator 6 has a feedback loop and frequency
modulates Operators 3, 4 and 5.
Note that even though Operator 6 is shown with
three separate output connections, it’s the same
modulation signal in all three outputs.
Modulators
Carriers
Feedback loop
Audio output
OUTPUT OUTPUT
4
5
1
2
1
2
3
6
4
5
1
2
3
6
OUTPUT OUTPUT
5
1
2
3
6
OUTPUT
4
5
1
2
3
6
OUTPUT OUTPUT
4
3
5
6
OUTPUT OUTPUT
321 4 5 6 7 8 9 10 11 12 13 14 15 16
4
OUTPUT
1
2
3
4
5
1
2
4
3
5
6
OUTPUT
1
2
4
3
5
6
OUTPUT
1
2
4
3
5
6
5
6
5
6
5
6
OUTPUT
1
2
3
4
5
6
1
2
4
3
5
6
4
5
1
2
3
6
OUTPUT
4
5
1
2
3
6
1
2
3
6
4
OUTPUT
1
2
3
4
OUTPUT
1
2
3
4
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
OUTPUT
1
2
3
4
5
6 6
OUTPUT
4
5
1
2
3
6
OUTPUT
4
5
1
2
3
6
OUTPUT
1
2
3
6
OUTPUT
4
5
OUTPUT
5
1
3
6
4
2
OUTPUT
5
1
3
6
4
2
OUTPUT
5
1
3
6
4
2
OUTPUT
5
1
3
6
4
2
OUTPUT
5
1
3
6
4
2
OUTPUT
5
1
3
6
4
2
5
1
3
6
4
5
6
4
2
OUTPUT
5 5
1
3
6
4
2
OUTPUT
1
3
4
2
OUTPUT
1
3
2
5
6
6
5
OUTPUT
1
3
4
2
4
1
3
2
OUTPUT
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