[PD] making puredata headphone-safe

[Hans-Christoph Steiner]

On Aug 29, 2011, at 12:19 PM, Martin Peach wrote:

> On 2011-08-29 11:52, Hans-Christoph Steiner wrote:
>>
>> On Aug 23, 2011, at 3:43 PM, Martin wrote:
>>
>>> On 23/08/11 03:29 PM, Stephen Lavelle wrote:
>>>> I've managed to hurt my ears twice over the past two days when  
>>>> using
>>>> PD w/ headphones. Even at lowest system volumes, it seems that
>>>> Terrible Things can happen. Are there any precautions that I can  
>>>> take
>>>> to make it feel less like I'm taking my life into my hands when I
>>>> have to use headphones?
>>>>
>>>>
>>>>
>>>
>>> Try making a [noise~] connected directly to a [dac~] and set the
>>> headphone volume so you can live with that. Nothing will ever be
>>> louder than that.
>>
>>
>> Hmm, I don't think that's actually true in all cases. On a MacBook  
>> Pro
>> running Mac OS X, I've had the volume set to one above mute, but had
>> massive feedback from LPC patches that were very very loud. [noise~]
>> would be very comfortable at that volume setting. I think some  
>> platforms
>> do the output mixing in the digital domain, so my min volume would be
>> [*~ 0.01], so that this would still make a very loud sound:
>>
>> [noise~]
>> |
>> [*~ 999999]
>> |
>> [*~ 0.01] (i.e. the Apple output mixing)
>> |
>>
>> In this particular case, the sound output actually gets shutdown
>> entirely, so you have to reboot to get sound output again.
>>
>
> That make no sense. How can you have two sounds at the same level  
> going into a mixer that come out at different levels? Or do you mean  
> that a squealing sound is perceived to be louder than white noise?  
> Maybe you could demonstrate with a patch?
>
> Martin
>
> "If it seems like magic your assumptions are wrong." Martin Peach

I am taking a biologist's approach here: I've observed this happening  
multiple times in the wild, now I have to figure out why.  Its very  
reproducible, I've taken the field mice into the lab and seen them  
reproduce ;)  Take Ed Kelly's fun LPC cross-synth example, in ekext/ 
examples/lpc-cross-synthesis.pd.  Put some loud samples into it and go  
crazy with the parameters and... MELTDOWN!  I've never heard my  
computer make a louder sound...  I knew that this patch has some  
feedback aspect to it, so I was doing my standard practice, having the  
volume very low.

.hc

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