Direct recording of digital audio signals

[audiodef]

I was just reading "Principles of Digital Audio" (I've read the third edition and was reading the sixth edition for the first time) when I was struck by a thought.

After I picked myself up and reported the thought to the police for assault and battery...

Most of my synths are digital. Be they analog modeling or otherwise, just before the audio outs, the signal is already digital. The signal goes through a D/A converter, travels to my mixer, where it is then re-sampled by Ardour when I record.

Is it just me, or is there a completely unnecessary step in here? Is there any way to simply send the already digitized audio signal to Ardour and bypass the need to re-sample a signal that was already a sampled signal to begin with? Or is my understanding of digital synth technology completely off (if it is, please be gentle!).

[Blue Hell]

Sure, could do that ... for instance the capybara has digital I/O only and needs an external converter to get analog auudio from it (or it can render to a file) ... also audio interfaces tend to have digital I/O more and more ... but there would be some syncing issues for an all digital solution, like you'd probably want a central clock to sync up all devices involved (or otherwise you'd still have to resample to iron out speed differences ... also with consumer grade digital audio clock loops are quite interesting ).

It's just not very practical right now I think as people tend to have loads of analog stuff.

[Antimon]

Some synths and stuff have S/PDIF jacks, which are digital. As Jan says there are sync issues, and you run into them quickly.

E.g. if I want to hook up my Line6 Pod X3 to the computer using S/PDIF, I have to change the sync settings on the sound interface for my computer so that the Pod is master. Otherwise I get regular spikes in the sound as the Pod loses sync and realigns.

Then, when I turn off the Pod I have to remember to turn the sync back to using the computer as a master, or there is no sound. I spent quite some time (on several occasions) in the beginning being frustrated at my computer for being completely silent before realizing that it was slaved to S/PDIF with no master around.

Also, I've heard stories about synths (I think it was the Origin) that use some standard clock frequency on the S/PDIF (e.g. 44.1 kHz) which is lower than what is used in the D/As that are connected to the analog outputs (e.g. 96 kHz), meaning that resolution is actually lost when transferring sound digitally rather than as analog sound.

So the idea about sending sound digitally is a great one, and it's sometimes possible, but there are enough practical hurdles to make you want an analog alternative around - for now.

/Stefan

[audiodef]

What's the Pod? iPod?

Maybe this is an idea I can take with me to grad school in audio tech. Assuming I get in, of course.

[Antimon]

Line6 Pod - guitar amp simulator and stuff.