Newbie: generating sound using an equation

khaki

hi, i have no experience with PD and need a help how to:
generate sound using a specific equation in realtime. how woud you do that in pd?
i want to be able to change several parameters of the equation by mouse - in realtime. For example: the equation for calculating the amplitude of a sample might be something like this:
a = sin(x) / sin (y)
where x and y are the mouse coordinates.
I know there are objects like sin~ or cos~ in pd for creating oscilators, but i need to calculate the amplitude using more complicated expresions.

i suppose i need to calculate a number of samples into a buffer and then play the buffer, while calculating new saples, but i dont know how to do that in pd.

if you have an idea how to patch something like ive described, please give me a hint.
thanks a lot.

hardoff

>a = sin(x) / sin (y)
where x and y are the mouse coordinates. <

you'd have to move your mouse up and down at least 40 times per second to even make that audible. (frequencies lower than about 40hz are generally not picked up by human ears)

>i want to be able to change several parameters of the equation by mouse - in realtime.<

unless you have a 3d mouse, you're only going to be able to change 2 variables at any one time.

>I know there are objects like sin~ or cos~ in pd for creating oscilators<

there is no sin~ , it's called osc~

>but i need to calculate the amplitude using more complicated expresions.<

fm synthesis, at it's simplest looks like this:

[a (
|
[osc~]
|
[*~ b]
|
[osc~]

one oscillator oscillates the frequency of another, a = modulator frequency, b = carrier frequency

obiwannabe

Have a look at the attached patch.

As Hardoff syas, you cannot convert mouse movement directly to an audio signal as it is too slow. However if you first convert it to a signal and then interpolate it with a simple filter before scaling it you have something that can be used directly as a parameter in an audio rate equation. In this case the X axis changes frequency and the Y axis modifies amplitude.

This only works for one quadrant of mouse. In other words negative X and Y values are mapped back into the +/+ quadrant but with phase reversed.

http://www.pdpatchrepo.info/hurleur/mouse-scratcher.pd

nestor

@khaki said:

For example: the equation for calculating the amplitude of a sample might be something like this:
a = sin(x) / sin (y)

i think you guys missed the fact that he(?) is creating an amplitude. I'm assuming this would be an envelope for another signal?

Try this:

Using [HID] or [gemmouse] for your mouse input.

This will be "jumpy" though, the result is calculated in control time. For a signal try;

It might work?