This is frightening - if I were a musician reading this I'd be frightened to ever use Appe software in a serious project.
(Of course, we do't know what happens in Windows under the hood either. The only way you can truly know what you're getting is to use an open-source OS.
cheers Miller
On Sun, Dec 29, 2013 at 12:12:04PM -0500, Martin Peach wrote:
On 2013-12-29 10:08, Alexandre Torres Porres wrote:
here's the deal, if I have a square wave in Pd running at 1 -1 peak to peak, then you say that should be my maximum output, right?
Thing is that if I give it an extra boost (say, multiply it by 2) I can clearly listen an increase in loudness. Hence, something in my system is allowing some headroom to be output.
I got a macbook air from 2010 running 10.7.5... if Pd is not responsible for this, maybe my hardware + Mac OS is?
Yes it's a Mac-specific issue. On Win7 I get no difference above 1.0. The Apple audio driver is responsible for "clipping" values outside of [-1.0..1.0] as they arrive from possibly multiple applications. The docs state that clipping can be done in a "soft" way, so I suspect that the default driver (for the headphone output) is doing some sort of compression. Possibly if you use an external interface this won't happen (?).
(see for example https://developer.apple.com/library/mac/documentation/DeviceDrivers/Conceptu... ) Martin
here's the patch, try yourselves and tell me what you get please.
Cheers
#N canvas 653 26 257 182 10; #X obj 79 97 dac~; #X obj 85 41 square~ 440; #X floatatom 125 72 5 0 0 0 - - -; #X obj 85 70 *~; #X connect 1 0 3 0; #X connect 2 0 3 1; #X connect 3 0 0 0; #X connect 3 0 0 1;
2013/12/21, IOhannes m zmölnig zmoelnig@iem.at:
On 2013-12-21 14:58, peiman khosravi wrote:
However, it's probably wise to clip the signal before sending it to dac~. Entirely for health and safety reasons!
this really depends...a clipping sine will have loads of high frequencies that might be equally damaging to your audience.
if you want to be safe, use math to make sure that your signal won't exceed -1..+1 before sending to the [dac~].
or use a limiter (zexy has a handy one).
fgmrdsa IOhannes
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