Re: Real-time category

[Stefan Tiedje <Stefan-Tiedje@addcom.de>]

Matthias Grob wrote:
>> I think if you just deliver a dc (a switch with a battery), even to an 
>> audio interface which does not pass dc itself, you should easily 
>> detect this loud click and use it as a trigger.
> 
> sure, I had not understood audio trigger this way. Interesting idea... 
> the foot switch would send such an audio trigger at each pedal press to 
> transmit its exact timing and in parallel send the MIDI command to give 
> the trigger its meaning? And then hope that the MIDI command arrives 
> first...
> It would require its own specific Audio/MIDI interface so the user would 
> not even notice that one audio channel is spent for this!
> Did you plan or even do this or did it just come up here? :-)

For my personal needs I never needed that precision and would rather 
keep my audio ins for musical input, but I've done a lot realworld 
problem solving and I am sure its possible to make it run with an 
afternoon... (you guessed right, it just came up here)

> ok, the time stamp may be a lot more acurate than the execution. 
> Depending on what the MIDI event means, its delay can be corrected with 
> the timestamp (do you do that?) or not. For example the loop lenght can 
> be corrected with the time stamp of the two Record commands, but we want 
> the old loop to shut up immediately at StartRecord, so the time stamp 
> does not help, so the time from the interrupt to its interpretation in 
> the audio app plus the fade out time counts, correct?

If you want to shut up something, you'd always want to fade it out, fade 
out is way less critical than triggering in terms of timing. Usually 
you'd even add some reverb, or have a pretty long fade time (magnitudes 
longer than usual response time) to let it feel more natural.
By the way, start recording and stop playback are completely independent 
in my software loopers, they could be triggered by the same event 
though. The timestamp idea should just explain how you could deal with 
information in general. You would definitly need this technique if you 
network several computers, as networks are optimized for throughput and 
not for realtime applications.
For my live setups with one computer I never needed timestamping yet, 
but I will introduce this into my next projects, for just keeping an 
order and information about events in general. It will certainly improve 
the overal timing as well.

Stefan

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         Stefan Tiedje
         Klanggestalter
     Electronic Composition
               &
         Improvisation

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