Re: [chuck-users] Filters blowing up: any news?

1 Apr 2010


      I found a great way to blow up RezonZ today.  Give it a freq value  
beyond the sample rate.
Noise n => Resonz z => dac;
1.0 => z.Q;
Std.mtof(440) => z.freq;//whoops!!! -- gave mtof a cps value instead  
of a midi value.
This gets REALLY loud on a Mac.
Hope this gets looked at.  In the meantime watch your ears.
Later.
Kurt
........................................................
http://www.kurtKotheimer.com
.......................................................


On Mar 1, 2010, at 4:48 PM, Tomasz Kaye's brain wrote:
...
Hi Robert. Thanks for the pointer, that's very useful.
I'd stayed away from RezonZ until now because I thought it would be  
wisest to begin by using filter types I already knew (or thought i  
knew) from other environments: LPF BPF and HPF.
I saw that RezonZ doesn't have the runaway tendency of the other  
three when plugged into the test patch (and now I think I understand  
the significance of the line in the RezonZ ugen documentation:  
"keeps gain under control independent of frequency").
I'll have a try at getting RezonZ act as a rough approximation of  
the other three filter types (any further pointers anyone can offer  
in this direction would be great), and try again to do some reading  
around musical applications of biquad filters, though filter-related  
writing tends to make my head hurt :)
On Mon, Mar 1, 2010 at 9:00 PM, Robert Poor  wrote:
Tomasz:
I use SndBuf => ResonZ => Envelope => DAC frequently in live
performances.  Even though the center frequency and Q of the ResonZ
are controlled by pitch bend and modulation wheel (respectively), I've
never had any problems with stability.  Am I missing something?  :)
- Rob
...
About the filter problem: does it mean that currently no one is  
using chuck
for classic sutractive synthesis patches like:
Oscillators -> Filters (cuttof driven by an ADSR) -> Amplifier  
(Level driven
by an ADSR) ?
Are people just not doing this kind of routing in ChucK yet, or  
are there
workarounds that avoid the filters going unstable when modulated  
in this
way?
(Sorry to keep on about this, but I'm really keen to keep using  
ChucK if at
all possible)
2010/2/17 mike clemow 
...
OT:
2010/2/16 Andrew C. Smith 
...
Seems that ChucK can crash brains, not just computers!
Chuck's filter code is actually written in Sumerian.  The Goddess
Asherah
...
created Chuck to erase peoples' minds and make them worship her.   
The sound
is actually a nam-shub and if you hear it, you will lose your  
wits and start
mumbling Sumerian syllables...
(sorry, i couldn't help this outburst.  i finished the book just  
a few
short weeks ago.  ;)
-Mike
...
Actually, my other solution was to run the audio through Jack
and into
...
Logic, where I can do a much better job of controlling the  
volume. This
actually doesn't distort (since the distortion comes at the dac  
level), and
changes the sound entirely. Anyway, just an option.
-Andrew
On Feb 16, 2010, at 5:03 PM, Kassen wrote:
2010/2/16 Stefan Blixt 
...
If you do SinOsc s=> dac and the 100.0 => s.gain, are you then
able to
...
blow a speaker on a Mac laptop even if it's main volume is  
turned down?
That's the curious thing to me, how the filter messes up so  
badly it makes
my MacBook's speaker scream even though the volume is almost  
down to zero.
100? Try something like this value for a output; 242210436022272.0
That's a actual recorded output of .last(). I'm not sure what  
would
happen if something of that volume would be played back on real  
speakers;
there is probably a UN convention against that kind of thing ;-).
From what I understand of the situation you wouldn't blow the  
speaker. If
Apple was smart they put in a pre-amp that's slightly smaller
...
...
...
maximum load of the speaker yet slightly over-speced for the  
output of the
dac to keep repairs down. But yes; apparently you will can get a  
very high
volume even though the (software) fader is down.
This is what we know.
Then from that I speculated (and unless something more credible  
comes by
I think it's a good theory) that Apple is doing everything in  
float (with
virtually unlimited headroom for practical applications),  
setting the master
volume with a floating point multiplication, and handing the  
resultant value
to the dac where inevitably it will be turned into a plain  
integer. In this
case that integer will be the highest volume the poor little dac  
can take.
If that's not it I can't imagine why +/- some 15 digit number  
would have a
higher amplitude than +/-1, as a final output, post master fader.
This is cheap compared to tweaking the voltage on the final  
hardware amp
(which would always preserve the full bit-range) and probably  
sounds a lot
better than going integer and throwing away a lot of bits at low  
volume, but
it fails to take into account that we may not just turn the  
volume down for
a more pleasant listen but also to protect our ears. Combine
...
...
...
potentially very sensitive studio or DJ headphones and you have  
a situation
that may lead to hearing damage. I know that my own pro DJ
...
...
...
output a lot more volume than my mid-range earbuds at the same  
volume
setting for a headphone jack.
IMHO this would be a oversight by Apple and I'm a bit surprised
...
...
...
hasn't been a storm of practical joke mails aimed at OSX users  
featuring
videoclips embedding floating-point audio. I'd offer at least a
...
...
...
output limiter like what has been proposed for mp3 players. I  
don't believe
in those for protecting children's ears through mandatory  
regulation because
of the differences in headphone output volume, but for user-set
2010/3/1 Tomasz Kaye's brain :
than the
that with with
headphones will
there
optional
protection
...
...
...
it might be a good idea. Of course ChucK is a bit more likely to  
cause this
sort of issue than the average off-the-shelf audio player.
Here is the original topic if you'd like to try to reproduce the  
findings
so far; http://electro-music.com/forum/viewtopic.php?t=37921
Yours,
Kas.
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http://semiotech.org
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Re: [chuck-users] Filters blowing up: any news?

Kurt Kotheimer