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

Robert Poor rdpoor at gmail.com
Mon Mar 1 15:00:04 EST 2010


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

2010/3/1 Tomasz Kaye's brain <tomasz.brain at gmail.com>:
> 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 <michaelclemow at gmail.com>
>>
>> OT:
>>
>> 2010/2/16 Andrew C. Smith <andrewchristophersmith at gmail.com>
>>>
>>> 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 <stefan.blixt at gmail.com>
>>>>
>>>> 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 than the
>>> 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 that with with
>>> 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 headphones will
>>> 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 there
>>> 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 optional
>>> 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 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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>>> https://lists.cs.princeton.edu/mailman/listinfo/chuck-users
>>>
>>>
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>>
>>
>>
>> --
>> http://michaelclemow.com
>> http://semiotech.org
>>
>>
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