[PD] channels and dac

[Derek Holzer]

Howdy,

Atte André Jensen wrote:
> Nikola Jeremic wrote:
> 
>> first set the number of channels you need with jack
>> run pd with jack-audio
>> make object
>> [dac~ 1 2 3 4 5 6 7 8
> 
> That's possible. However what I'd like to do is to simply run "pd" 
> (without -channels) and then be able to somehow *in a pd patch* select 
> how many channels to use.

Well, without any flags defined by the starting command or the saved 
settings, then PD would start with two channels (stereo) and adding more 
with the [adc~] or [dac~] would have no effect.

> 
>> it depends on your patch... more processing - more cpu :) so i belive 
>> more channels - more cpu
>> corect me if im wrong
> 
> I believe the same as you, but I'd like to know :-)

I can tell you for sure that extra channels add extra CPU, due to PD 
maintaining connections with the audio drivers. I notice this when, for 
example, I use my Hammefall DSP with -channels 18 instead of -channels 2 
or -channels 8 or whatever. Some audio drivers are "greedier" than 
others, so switching between them can show you a difference in load.

Of course, you can always test these things yourself ;-)

best,
d.

-- 
derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
---Oblique Strategy # 67:
"Emphasize the flaws"