How to obtain a value for a variable in a codebox

oddson · 2 Aug 2012

streamin x; streamin y; streamin z; streamout out;

out = x>y & z;

Not sure what you mean by 'obtain a value in a code box'. But the above gives z as output when input x is greater than input y.

distante · 3 Aug 2012

I mean, if for example, I put 0.7 in a float box (that is obtained from a knob), so I want to use that 0.7 as a variable in the code box to do equations or so.

*Edit*

Oh! I see, I can use streamin, thanks 😀

Following your example, the ">" operator generate a mask don't? so, If x>y is false then out will be 0 ?? 😊

oddson · 3 Aug 2012

distante wrote: ...Following your example, the ">" operator generate a mask don't? so, If x>y is false then out will be 0 ?? 😊

Yes??

I first wrote it as if x>y then z and if x<=y then x but decided you weren't asking for that... if you were then

... out = x + (x>y) & (z - x);

distante · 3 Aug 2012

Great thanks again, Takes a little bit to understand the Mask thingy,

As I said, I'm trying to do a simple hard limiter, but I din't take in consideration that the signal is bipolar, so I pass from -1/ 1 to 0/- 1 and check if the signal vs my threshold, but I think is the wrong approach because when I go back to -1/1 the signal gets weird

streamin SignalIn; // señal de entrada streamout SignalOut; // señal de salida streamin Ceiling; float Temp;

//interpolo -1|1 to 0|1 // simplemente sumo uno y divido entre 2

Temp = (SignalIn + 1)/2;

Temp = Temp>Ceiling & Ceiling; Temp = Temp + (Temp>Ceiling) & (Ceiling - Temp); // vuelvo de 0|1 a -1|1 // Resto uno y multiplico por 2

Temp = (Temp *2) -1;

SignalOut = Temp;

trogluddite · 3 Aug 2012

distante wrote: Takes a little bit to understand the Mask thingy,

Yes - especially if, like I was, you are used to having 'If..Then..Else' type commands in other languages! The key is just to remember that... Value & False = 0; Value & True = Value; So in this case, if Size is within the celing, we get... Size = Size + (FALSE) & (Ceiling - Size) ---> Size = Size + 0 ---> Size = Size If Size is greater than the ceiling... Size = Size + (TRUE) & (Ceiling - Size) ---> Size = Size + Ceiling - Size ---> Size = Ceiling.

distante wrote: take in consideration that the signal is bipolar,

When it comes to an audio signal (+/-1), large negative numbers are equivalent to large positive numbers in terms of how 'loud' the signal is. So to find the signal level for a limiter (or compressor/overdrive etc.) what you really need is the 'size' of the peaks, regardless of whether they go up or down - the distance from zero, so to speak.

The code box has a couple of functions that are very useful for this... abs() - gets the 'absolute' value, i.e. it removes the minus sign from negative numbers. sign() - finds if a number is positive (returns 1) or negative (returns -1).

To use these for your comparator function, the code would look something like this...

streamin In; streamin Ceiling; streamout Out;

float Size; float Direction;

Size = abs(In); //Distance from zero Direction = sign(In); //Positive or Negative

Size = Size + (Size > Ceiling) & (Ceiling - Size); //Keep Size within the ceiling Out = Size * Direction; //Restore the sign so that the sample 'points' the right way.

Note that, currently, this is just a hard clipper, rather than a limiter - because there are not the attack and decay times that would even out the reaction time for a smoother sound. For those kind of functions, this little code snippet can provide the beginnings...

Size = abs(In); Direction = sign(In) Over = Size - Ceiling; //How far above ceiling Over = max(0,Over); //Over never less than zero (i.e. can be 'over' but not 'under') //NB: max(x,y) returns whichever is the biggest of two numbers Size = Size - Over; Out = Size * Direction;

This does exactly the same thing, but the 'Over' variable now tells you how far beyond the threshold the signal is - monkeying around with this number is then the key to all kinds of dynamics control.

distante · 3 Aug 2012

Thanks a lot oddson, following your tips and codes I have now a mono hard clipper, for now is all I need (protection for digital clipping).

I wrote down all the limiter/compressor considerations thought, I will need them later.

I'm on my way to pass this to a stereo Hard Clipper!

😀 thanks again ! 😀