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

Tue Mar 2 08:22:50 EST 2010

@mike again. I made a little video showing the max equivalent of the
principle I'm hoping to be able to apply in ChucK: http://vimeo.com/9852367

On Tue, Mar 2, 2010 at 11:19 AM, Tomasz Kaye's brain <tomasz.brain at gmail.com
> wrote:

> @mike
>
> I'm not sure about Supercollider, but in max, i generally use the svf~
> object: a state variable filter with separate outputs for LPF HPF BPF and
> band stop. It doesn't blow up when you modulate its cutoff or resonance
> inputs, so it's very straightforward to plug into subtractive synthesis
> patches. I'm looking for a similarly 'tolerant' filter ugen (or collection
> of ugens) in ChucK.
>
> 2010/3/1 mike clemow <michaelclemow at gmail.com>
>
> Curious...
>>
>> Is there a difference between the way that filters blow up in, say,
>> Supercollider than there is in Chuck?  Because my understanding is that
>> those algorithms just...  blow up, if you push on them too much.  Am I wrong
>> here?  It wouldn't be the first time...
>>
>> ;)
>>
>> Mike
>>
>> 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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>>>>> chuck-users at lists.cs.princeton.edu
>>>>> https://lists.cs.princeton.edu/mailman/listinfo/chuck-users
>>>>>
>>>>>
>>>>>
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>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> http://michaelclemow.com
>>>> http://semiotech.org
>>>>
>>>>
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>>
>>
>> --
>> http://michaelclemow.com
>> http://semiotech.org
>>
>>
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