[chuck-users] phase modulation and hard sync?

[Alexandre Torres Porres]

2017-06-03 15:01 GMT-03:00 Jean Menezes da Rocha <jean at menezesdarocha.info>:

> Unfortunately, my knowledge of SuperCollider is very limited and I don't
> feel like I'm able to translate your code.
>

Here's an attempt to make SC code clearer.

Here's the fm example I found in chuck, using sync = 2

////////////////////////////////////////////////////

SinOsc m => SinOsc c => dac; // modulator to carrier

400 => c.freq; // carrier frequency

201 => m.freq; // modulator frequency

1500 => m.gain; // modulation index

2 => c.sync; // FM synthesis (sync is 2)

while( true ) 1::second => now; // time-loop

////////////////////////////////////////////////////


And now for the SC equivalent


////////////////////////////////////////////////////

{var carrier = 400; // carrier frequency

var modulator = 201; // modulator frequency

var index = 1500; // modulation index

var m = SinOsc.ar(modulator) * index; // modulating signal

var c = SinOsc.ar(carrier + m); // frequency modulation (carrier +
modulating signal)

Out.ar (0, c ! 2)}.play

////////////////////////////////////////////////////


and now a phase modulation example in SC


////////////////////////////////////////////////////

{var carrier = 400; // carrier frequency

var modulator = 201; // modulator frequency

var index = 2pi; // modulation index

var m = SinOsc.ar(modulator) * index; // modulating signal

var c = SinOsc.ar(carrier, m); // frequency modulation (carrier +
modulating signal)

Out.ar (0, c ! 2)}.play

////////////////////////////////////////////////////


note, the SinOsc in SuperCollider takes frequency input as the first
variable in parenthesis, and phase (in radians) in the second.


cheers

2017-06-03 15:31 GMT-03:00 Alexandre Torres Porres <porres at gmail.com>:

>
>
> 2017-06-03 15:01 GMT-03:00 Jean Menezes da Rocha <jean at menezesdarocha.info
> >:
>
>> Alexandre,
>>
>> As far as I understand it, the .sync attribute is more like an
>> identifier, rather than a true numeric value (that is, 0 says you are
>> syncing frequency with frequency; 1 says that you are syncing phase with
>> frequency; 2 says you are doing true Frequency Modulation). As you are
>> telling that no value means no sound, one can infer that there is no
>> default value for that, and if you are feeding UGen => UGen, telling which
>> is your sync method is mandatory (but I can be mistaken, as usual).
>>
>
> there may be a default parameter, right? And that seems to be 0. If I have
> sync at "0", I hear no sound.
>
> Anyway, it doesn't seem like the sync parameter is able to do hard sync.
> It seemed that the "0" value would do that, but, as I said, I hear nothing.
>
> If phase input is linear in chuck, then the code from SuperCollider would
> be equivalent, but it is not. And even if it wasn't linear, I tried it with
> radian values and did not get the same results.
>
> I suspect it is not really doing phase modulation because it doesn't
> matter if I change the carrier frequency, and that is weird.
>
> well, I guess I'm repeating myself, sorry, just anxious in the hope of
> clarification.
>
> thanks
>
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