[chuck-users] Filter screaming: danger to hearing

[David M]

I'm aware that this is what happens what a filter is set at a negative
value, and I guess from this example that the same thing happens at high
filter values. (Maybe the value is looping?) I've never noticed this problem
when the filter is keep > 0 and < 10000, so I think you can avoid it like
that until a fix is given. But yes, the resulting sound is always at max
volume.

On Sat, Nov 28, 2009 at 11:09 AM, Tomasz Kaye's brain <
tomasz.brain at gmail.com> wrote:

> Hello all. I know that Kassen already posted to the list about (what
> seems like) a filter instability problem in certain situations. But
> after a conversation with him it seemed that I hadn't conveyed the
> full nature of the problem clearly, so in this post will try to do
> that.
>
> To recap, here's some code from Kijjaz that demonstrates the problem:
>
> PulseOsc osc => BPF filter => blackhole;
> 20000 => filter.freq;
> 0.5 => filter.Q;
> for(int i; i < 100; i++)
> {
>    <<< "osc: ", osc.last(), " filter: ", filter.last() >>>;
>    samp => now;
> }
>
> The value output by the filter keeps rising.
>
> I ran into this problem while i had a similar patch connected to dac
> instead of to a blackhole. I was wearing headphones, but i took the
> usual precaution of turning my macbook volume to the lowest level
> above 0 before running the patch. To my alarm, the resulting screaming
> sound came through my headphones at top volume anyway. It turns out
> that when set to any of the volume gradations above 0, the screaming
> happens at effectively full volume on my macbook.
>
> So the point of this extra post is to emphasise that (at least for mac
> users) the filter screaming issue is currently quite dangerous for
> hearing/speakers, even if you take (imo) normal sensible precautions
> before running a patch.
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>



-- 
David M
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