I have a grid controlling two sliders which control the cutoff frequency and resonance of a filter i have made. I also want to be able to turn the cutoff frequency up and down by holding down z and x and change the resonance using . and ;.

So far I have used the key and select objects and made it so that when you press the desired key it adds or takes away the respective value for the slider.

The problem with this is that it only moves one increment when you touch the key and doesn't output the same message when you hit the key again, so you cant get around the problem by tapping the key alot.

What I am looking for is an object that continuously outputs its received data when a key is pressed and stops outputting the data when the key is released.

Does anyone know of one that exists?

Thanks in advance for your help!

I looked at something like that briefly, and it seems that you'd have to first get your OS to turn off the key repeat so you don't receive a bunch of rapid keydown-keyups if you hold it down.

Other than that, you should be able to do that through some fairly simple programming - just make an abstraction that will keep track of and increment the slider's value when it receives a bang, make another abstraction that outputs bangs when it sees you've pressed a certain key and stops when you release it, and wire them together.

First of all thanks for that mate!

That makes perfect sense except that when i hold down a key it doesnt send out a rapid bunch of key-downs and key ups.

It only sends out the number attached to the key object when i press the key once, and doesnt send out a stream when i old it down.

If i can make it send out a stream of key down I can make it change the slider for every keydown value and to stop moving it when it receives the key up.

So how do i change my OS so that in pd when i attach the key object it continally outputs the number of the key i am holding down?

check out [keyname], [key], and [keyup] if you haven't already, what do these give you for outputs?

yeah as slvmchn says, you need to get both the key down and key up strokes.

i think [key] and [keyup] is the easiest way.

so.. what you do, using key 113 (q) as an example, is this:

[key 113]
|
[1 (
|
[metro 50]

and then, into the same metro:

[keyup 113]
|
[0 (

the speed of your metro is the speed at which bangs are output.

Works now thankyou very much! had to use the select object but works perfectly now!

My next problem is how to modulate my cutoff frequency with an lfo?

An osc~ outputs signal and i dont know how to get that to modulate a control value, anyone know?

Thanks in advance!!!

[osc~] [metro]
| |
[snapshot~]
|
[$1 10(
|
[line]
|
[expr a * $f1 + b] (to scale to the right range)
\
[lop~]

I completely understand the first bit but wat happens in the expr a*.. box, that doesnt make sense to me!

Sorry for being dumb and new to puredata but if i know what that means i will be so happy!

and why do you put $1 10 in the message box?

Sorry, if you explain it to me like im a complete dunce i will probably understand!

Thanks again

expr evaluates a mathematical expression. $f1, $f2, ..., refer to the values coming in on the expr's inlets. You should substitute appropriate values so for a and b so you get the values you want instead of the 0 through 1 coming out of the osc~.

The [$1 10( going into the [line] is so that the values will ramp smoothly, since snapshot~ will only give you values as often as the metronome ticks and will therefore be a little jumpy. Actually, instead of [$1 10( you should put [$1 where x is the same number you used for the metronome's creation argument.

I managed to get it working by rescaling the 0 and 1 that the osc~ outputs and used the mtof object to convert this into a cutoff frequency.

The problem with this is that it is not 100% accurate for what I am trying to do.

I want to have maximum cutoff at 10k for the hi pass but obviously not the low pass because that would make it impossible to leave the signal unaffected.

I need to know the best way of logarithmically scaling the cutoff frequency, basically i need an equation to scale 0-1 to 20-20000 logaritmeically.

any ideas?

Thanks alot by the way this has really helped!