[Faudiostream-devel] DSP questions

[Darren L. <dar...@sb...>]

This only obliquely relates to FAUST, so please forgive my being 
off-topic. However, the last time I asked questions on the Music-DSP 
list, I got brush-offs about "trade secrets", so I don't really bother 
with them anymore.

I found a screenshot on the Reaktor web site:

http://www.native-instruments.com/uploads/pics/2lpcellstruct_02.gif

I've been trying to figure out what the integrators are doing, when it 
suddenly hit me that they probably each have a different function they 
are integrating (no doubt double-clicking on them in Reaktor would 
reveal that). Now, numerically integrating inside of a computer is quite 
easy: all you need to do is add the current input to an accumulator 
variable and output the value of that variable every sample cycle.

I can't help but wonder if this structure is solving the differential 
equation for the filter in real time. Unfortunately, I'm only just now 
finishing the second of the calc sequence this semester (we've touched 
on differential equations), but I still think I could follow an explanation.

Also, if you were going to build a Reaktor-like application, what kind 
of basic building-block DSP routines would you like it to have? The 
arithmetic operators, of course (+. -. *, /), a single-sample delay 
line, a multi-tapped delay line, and a variable delay line are all 
givens I would imagine. To this, I've added an integrator. Anything else?

Thank you all for entertaining such a rank beginner.

Regards,
Darren Landrum
Wannabe-but-not-there-yet DSP expert :-)