[PD] making puredata headphone-safe

[IOhannes m zmoelnig]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 2011-08-24 02:33, Chris McCormick wrote:
> On Tue, Aug 23, 2011 at 06:48:05PM -0400, Martin Peach wrote:
>> An [osc~] multiplied by 5555 will sound louder  
>> but it won't actually be louder than an osc multiplied by one (the  
>> amplitude at the output will still be between 1 and -1).
> 
> I think it actually depends on your sound card whether or not this is true with Pd. I might be mistaken but I am pretty sure some sound cards will let you output abs(x) > 1. Hmmm actually this doesn't make sense to me if the driver is accepting a 16 bit signed int. Can someone confirm whether this is the case?

finally someone!

to clarify:
imho, you should never! assume that
[dac~] is equivalent to
[clip~ -1 1] -> [dac~]

whether or not your output signal will be clipped to -1..+1 is entirely
depending on your "sound infrastructure" (i'm mainly talking about
software here; depending on whether you use "portaudio", "mmio", "alsa",
"jack" and whatnot, your signal might be "converted" to some fixed point
format (mostly 16bit signed integers) or a floating point format just
before it leaves Pd.
in the former case, you will eventually experience clipping. in the
latter case less so.

after that, it is up to your "sound infrastructure" what to do with the
signal, and it might well boost it or clip it or whatever, before it
delivers to the hardware, which again might speak whatever format (e.g.
16bit unsigned int) that might impose clipping.

finally, your signal might get clipped at a number of places
will eventually get "clipped" (or distorted similarily) by your
amplifiers and/or your speakers.


if you do get clipping, then
[osc~ 440] ->  [*~ 440]
will usually sound more annoying (and louder) than a "loud 440Hz tone",
as you get plenty of harmonics.


> 
> Incidentally, if I recall correctly, Miller told me that he uses a set of small, cheap speakers when doing experimental stuff so as to save ear damage. At least I think it was Miller.
> 

for what it is wort, we have a huge red button labeld "panic" that
allows to mute all the 24 speakers in our CUBE, just in case your patch
goes havoc and you have innocent audience in the room.


fgmasdr
IOhannes
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/

iEYEARECAAYFAk5UplEACgkQkX2Xpv6ydvRa1ACdEDPyWLRydZtLM+GmsekmEpht
80EAnRh+K4xDs8cxp8ZO/mzf3Hs5Z012
=JzW1
-----END PGP SIGNATURE-----

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 3636 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://lists.puredata.info/pipermail/pd-list/attachments/20110824/d956fbb4/attachment.bin>