Language Problem

rogan

Hi all,

I'm writing a reverb package based on the Gardner reverbs found in <<The CSound Book>>, and I'm basically being held up by my own lack of understanding of chuck syntax.

I'm trying to implement nested allpass filters by adding a nesting function to my Allpass class (which I'll post when it's ready :) ). The problem is when I want to be able to nest any number of allpasses within my filter. I do this by trying to create an array of Allpass objects which I connect to one another. The problem in my code is that I don't instantiate my array of Allpass objects right, but I'm not sure how to actually do this correctly. Could somebody point me in the right direction?

Frostburn · Posted: Mon May 26, 2008 10:31 am Post subject:

ChucK doesn't support dynamic arrays yet. I could make an example that creates new arrays all the time but because ChucK doesn't yet have garbage collection either that's a bad idea. It's hard to write a correction when I don't know how you're classes are supposed work but I'll try to correct the nest function for you.

If you pass an Object to a function it's always a reference so the @ isn't necessary in the argument definition.

rogan · Posted: Mon May 26, 2008 10:51 am Post subject:

Thanks, Frostburn!

I went ahead and changed my nesting function last night, so that it either nests one or two allpass filters inside the main allpass (depending on how it's called). I'm not sure that I'll use more than two anywhere, but I always want to make my code as generic as possible.

I'll post my gardner reverbs tonight, after I've made a few modifications....

Inventor · Posted: Mon May 26, 2008 1:58 pm Post subject:

Hi rogan, are you related to the Japanese monster Rogan who battled Godzilla and lost? Of course you lost, nobody beats Godzilla! OK, I jest but every ChucKist must have a sense of humor, don't you think?

I am pleased to learn about your reverb work and it will be interesting to see your results. Please keep us posted and maybe even post some mp3's of your reverb software. Thanks and happy ChucKing!

rogan · Posted: Mon May 26, 2008 3:35 pm Post subject:

Hi all,

I've attached some preliminary work on Gardener Reverbs as presented by Hans Mikelson in <<The CSound Book>>. I'm running into the weirdest problem. I can't connect to my object with its "chuck" function (this is a method I borrowed from some of Frostburn's classes); instead, I get a nullpointer error ("NullPointerException: shred[id=1:combtest.ck], PC=[32]"). Can anybody see where I go wrong?

Here is my testing code

rogan · Posted: Mon May 26, 2008 3:37 pm Post subject:

Inventor, I must be a different sort of monster than the "other" Rogan. :)

Inventor · Posted: Mon May 26, 2008 3:47 pm Post subject:

Hey, as long as you can ChucK you're fine by me! : )

Frostburn · Posted: Tue May 27, 2008 1:02 am Post subject:

Nice to see someone doing class based UnitGens. Keep at it rogan. :)
Your syntax is a bit off... You are defining functions that crash ChucK by not returning what they are supposed to.
I started from scratch and made new allpass classes.

My knowledge of allpass filters and reverbs comes from around here. But I didn't read it too carefully so there might be some glaring errors in my implementation.

Attached is my take on the nested allpass design.

allpassexample.ck

Description:

Nested allpass implementation with UnitGen classes.

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allpassexample.ck

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rogan · Posted: Tue May 27, 2008 10:18 am Post subject:

Ah, interesting. I hadn't realized that my errors were coming from my NestedAllpass model. Thanks, Frostburn; it's always nice to have an extra pair of eyes. Once I had my stated return values correct, everything was fine. Also, those Allpasses should work the same as the ones I made.