[PD] Feedback discussion

Mathieu Bouchard matju at artengine.ca
Wed Sep 16 19:20:42 CEST 2009

On Wed, 16 Sep 2009, Derek Holzer wrote:

> As I said already, I'm not interested in predictability. Analog 
> nonlinearity is interesting to me, much more so than digital 
> pseudo-randomness.

I wonder what you mean by nonlinearity... it seems that there are wholly 
different definitions of it. Because I wonder why you compare those two 
things, and not also compare with digital nonlinearity and/or analog 

> But my main interest is in being able to maintain a live performance in 
> the midst of all this unpredictability.

That must take a lot of nerve... I hope that the audience can feel that 
you're dealing with impredictability.

> When digital stuff fails, it tends to fail catastrophically--in other 
> words NO SOUND. Game over.

I know what you mean. It might be because decisional processes are 
inherently digital, so, naturally, decisional processes is a thing people 
want to do with computers (because they can't do it with anything else), 
and then decisions always have an either-or aspect to them, which excludes 
gradual failing by necessity.

But if you mean hardware failures, then also yes, the large majority of 
digital crashes fail catastrophically, though the weirdest non-crashing 
hardware failure I have ever had was with trying to run GridFlow on a K7 
computer that had a really bad heatsink. In a wave propagation simulation, 
large garbage values would sometimes pop out of nowhere and replace a 
small or zero value. Because the wave propagation is a feedback effect, 
you'd see the computation error propagate itself as a wave across the 
screen. It was interesting, but for many other reasons (occasional hard 
freezes and data corruption) I had to add some extra cooling:


(And a few weeks later I defenestrated the whole box.)

> The "errors" that I get from analog instabilities are much more 
> interesting than anything I've managed to predictively compute.

Ah, that's another difference that is not a basic analog-digital 
difference. I play a lot with digital instabilities and I also play with 
digital stabilities that I haven't tried to predict.

Top-down processes use reason to predict and produce, whereas bottom-up 
processes start provoking a good source of interesting stuff and then sort 
through whatever come out of it. Naturally, finding and provoking a good 
source of interestingness are activities that also can benefit from reason 
and intuitions and a taste of adventure, all at once. In a top-down 
perspective, an error is something that you didn't want upfront, whether 
in a bottom-up perspective, an error is something that you don't want 
after it's done.

  _ _ __ ___ _____ ________ _____________ _____________________ ...
| Mathieu Bouchard, Montréal, Québec. téléphone: +1.514.383.3801

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