## 4 Operator FM

E8_Heterotic
Posts: 30
Joined: Wed Dec 19, 2018 4:05 am

### 4 Operator FM

This is a series of 10 modules. Each represents one of the 10 possible 4-operator FM algorithms/topologies. There is a volume control for each operator, as well as transposing and fine tuning of each operator. You can also control the waveform and duty cycle for each operator. The operators are labelled 1 through 4, with 1 always being an output for every algorithm and 4 always being a modulator. The 10 topologies are:

1 = 4>3>2>1
2 = (4+3)>2>1
3 = ((4>3)+2)>1
4 = 4>(3+2)>1
5 = 4>3>(2+1)
6 = 4>(1+2+3)
7 = (4+3+2)>1
8 = (4>2)+(3>1)
9 = (4>2)+(4+3)>1
10 = (4+3)>(2+1)

Here ">" means "modulates."

If you want to control ADSR on each operator, you can use an envelope generator and plug it into any one of the volume controls in the module(s).
4 Op FM.zip
4 Operator FM

nunrgguy
Posts: 23
Joined: Fri Oct 12, 2018 10:47 pm

### Re: 4 Operator FM

Thanks for posting these - really interested in this. However I can't for the life of me see how they work. They all seem to contain just a bunch of samplers that connect straight to the output? No waveforms in there and how does a modulator modulate a carrier. There's a metamodule in there too but not sure what that's doing?

E8_Heterotic
Posts: 30
Joined: Wed Dec 19, 2018 4:05 am

### Re: 4 Operator FM

nunrgguy wrote:
Wed Apr 03, 2019 1:34 am
Thanks for posting these - really interested in this. However I can't for the life of me see how they work. They all seem to contain just a bunch of samplers that connect straight to the output? No waveforms in there and how does a modulator modulate a carrier. There's a metamodule in there too but not sure what that's doing?
There are also 4 generator modules, labelled 1 through 4. The list I posted says what modulates what. All of the modulation is frequency modulation.

For example, algorithm 3 has generator 4 modulate generator 3, and then the sum of generators 2 and 3 modulate generator 1. The extra modules are so that you can separately tune each generator's frequency.

nunrgguy
Posts: 23
Joined: Fri Oct 12, 2018 10:47 pm

### Re: 4 Operator FM

Hi
Thanks for posting.
I understand perfectly how FM works that's not the issue. I've got 6 op and 4 op synths here and used to use a VZ1 which (on the phase of it....) was 8 op.
This is what I mean:
https://pasteboard.co/I8L06oD.png
That's algorith 4FM-1.
Every module is a sampler except for the metamodule (what is that doing?). All of the modules are routed straight through to the output via the amplifier, nothing modulates anything else (and all the algos are like that?). There are some codes in the pattern editor and a pattern that runs for a while at the bottom. I can't for the life of me see how this will operate as an FM synth? Where are the carriers and operators? There's nothing there to make a noise either or are you supposed to load single cycle waveforms into the samplers or something?

Cheers

E8_Heterotic
Posts: 30
Joined: Wed Dec 19, 2018 4:05 am

### Re: 4 Operator FM

nunrgguy wrote:
Fri Apr 05, 2019 10:27 pm
Hi
Thanks for posting.
I understand perfectly how FM works that's not the issue. I've got 6 op and 4 op synths here and used to use a VZ1 which (on the phase of it....) was 8 op.
This is what I mean:
https://pasteboard.co/I8L06oD.png
That's algorith 4FM-1.
Every module is a sampler except for the metamodule (what is that doing?). All of the modules are routed straight through to the output via the amplifier, nothing modulates anything else (and all the algos are like that?). There are some codes in the pattern editor and a pattern that runs for a while at the bottom. I can't for the life of me see how this will operate as an FM synth? Where are the carriers and operators? There's nothing there to make a noise either or are you supposed to load single cycle waveforms into the samplers or something?

Cheers
I don't understand. There are no sampler modules at all in any of the 10 FM operator modules. There are amplifiers, generators, and multisynths, but there is no sampler at all. The amplifiers are used to increase the FM depth beyond what one can get simply plugging one generator into another. The four generator modules are the green modules labeled with numbers. In the case of algorithm 1, for example, 4 modulates 3, which modulates 2, which modulates 1.

The generator modules are the operators. Audio rate output can be plugged into a generator module. The audio rate signal will modulate the frequency of the generator according to the "Freq. modulation by input" setting of the generator. In order to work, you must have the input signal and the generator playing at the same time. That's what the multisynth is for. You need to use the multisynth in order to play all the generators at once so that the full algorithm is used.

I don't see what sampler module you're talking about. There are 10 sunsynth files in the zip folder. Each is a metamodule which acts as a 4 operator FM synth with a particular algorithm.

Keres
Posts: 285
Joined: Mon Mar 21, 2016 9:41 am
Location: N. Tulsa Ok.
Contact:

### Re: 4 Operator FM

He has to be loading them.wrong... I just opened I e yo test it, works fine. Thanks!

Keres
Posts: 285
Joined: Mon Mar 21, 2016 9:41 am
Location: N. Tulsa Ok.
Contact:

### Re: 4 Operator FM

He has to be loading them.wrong... I just opened I e yo test it, works fine. Thanks!

nunrgguy
Posts: 23
Joined: Fri Oct 12, 2018 10:47 pm

### Re: 4 Operator FM

Maybe I'm loading them wrong but surely, irrespective of how you load something it should load the same? if I double click on one of the files how can sunvox be loading up what I've pasted in the screenshot I posted which was s what's loading into sunvox here. Is this a sunvox bug? How am I supposed to load them then?

Cheers

nunrgguy
Posts: 23
Joined: Fri Oct 12, 2018 10:47 pm

### Re: 4 Operator FM

Ah - I've got it, if you load from within Sunvox as a module it's all A-OK and editing the metamodule it shows all the correct components. Just wierd it loads of something completly different if you double click onit.

Thanks for the help. Now for some fun

philipbergwerf
Posts: 88
Joined: Sat Mar 17, 2018 4:23 pm

### Re: 4 Operator FM

Little technical question/sidenote: Why not use one amplifier and set gain to 10 instead of the megafier module? Nice work btw I am just learning by looking at the files...