guitar rig: how do they do it?

[ncc]

Hello,
I tried the demo of this new software based amp modeller and I like the
sound of it but this is not my point here.
http://www.nativeinstruments.de/index.php?guitarrig_us

It is similar to amplitube and other amp simulators but the cool thing about this product is a pedal board which I have not tried but the description of the product says it has:
- four pedal switches
- 1 expression pedal
- no MIDI, no USB, no special control between the pedalboard and
the computer, just the audio into the soundcard.


The only way I can imagine this working is if they modulate non-audible high frequency (control-signal) over the guitar sound and decode the data in their software.  Does it make sense?
Is there any other way to get this pedal working. I am thinking that
I would like to use the same technique for my DIY pedals providing it is
not too much trouble.

ncc

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[Athin]

:idea:  if the effect is mono they use the 'left' channel of the signal   :lol:

[ncc]

I don't know for sure. I only tried the demo with the
guitar directly in the computer, however this is a
good point, I didn't  think of that.

One channel for control the other for the guitar. that would work.
Thanks for the reply,

ncc

[loki]

I don't know for sure. I only tried the demo

I tried downloading the demo too, but when i try opening it, there's an error message that says the program can't open because my CPU doesn't support SSE or Altivec  :?  :?
What's your CPU?

[Mike Burgundy]

Using the other audio channel makes sense. A guitar signal is mono (unless you have a Rick or something), and it doesn't matter if the processor then makes it stereo by applying different (degrees of) effects to the tow different output channels.

[ncc]

loki,
Too bad it doesn't work for you.
My CPU is a just a regular 1Gig Pentium, pretty much obsolete
my today's standard but I have a good soundcard,
a soundblaster Audigy.

The spec only talks about the speed, 700Mhz minimum.

ncc

[loki]

loki,
Too bad it doesn't work for you.
My CPU is a just a regular 1Gig Pentium, pretty much obsolete
my today's standard but I have a good soundcard,
a soundblaster Audigy.

The spec only talks about the speed, 700Mhz minimum.

ncc

well that's odd... i have an Athlon XP 2200 and an Audigy 2  :?  :?
i'll try to email the company and ask them what can be wrong
thanks anyway

[RDV]

I think Windows XP is the way. Or a Mac.

RDV

[ncc]

Loki,
Your computer is twice as fast as mine, I would think it should work
even better & no delay. That's strange. I hope they help you figure out
how to test the demo sofware. There are lots of cool features in the package.
(The app is stand alone, has a metronome, tuner, recording/ mp3 playback, etc)


Athin, Mike,
You were right. I researched a little more and the documentation confirms it; "All parameter data is transmitted from the foot controller to the computer via a second dedicated audio channel, making Guitar Rig a completely MIDI-free solution without any setup hassles."

Soon or later, someone will put a scope on the control channel and we'll find out how complex or how simple the communication protocol is.

Thanks guys,

ncc