David Schuyeteneer wrote:
> 
> Can someone please explain me very clear and exactly what those
> weird A -, K - and I - RATES are ??? 

A-rate in Csound means audio rate, ie generated soundfile sample rate.
Sample rate in a digital sound file decides the sound quality.
Common values are: 44100 Hz (CD rate), 22050 Hz (usually ok when testing
an instrument), or 8000 Hz (web .au files - only good for speech)

It might be added that the sample rate also determines the highest 
representable pitch in a digital sound, namely half the sample rate.
Sample rate (sr) of 44100 can thus theoretically represent up to 
22050 Hz pitches - just above the highest pitch anyone can hear 
under the best conditions at any time in their life.
You'll find a section on this topic eg in most sampler manuals,
in help files for sound programs etc.

K-rate means "Control" rate. The ear cannot detect most musical changes
(like pitch change) at a very high rate. Csound saves computing time by
updating many variables at a slower rate. For most purposes 1/10th or 
even 1/100th of audio rate will do fine. At lower rates the stepping in
the variable changes will be too annoying.

I-rate is for init time. This is not properly a rate, it's for setting
a variable to an initial value when an instrument begins playing.


Regards,

	re