How To Re-amp with Eleven Rack and Pro Tools HD?

[Justin1524]

I'm a little confused on the best way to re-amp with Pro Tools HD. I'm using Eleven Rack and a 96 IO. Can someone give me a step-by-step including signal routing and when to change rig input to re-amp? Thanks.

Justin

[Justin1524]

bump

[Justin1524]

Anyone?

One thing that annoys me a little bit is that you can't send audio to Pro Tools HD over USB as you can with Pro Tools LE. Why doesn't Pro Tools HD recognize Eleven Rack as an audio device over USB? It's almost like Digidesign is crippling Pro Tools HD by not having this. Why? Because you can't send both a dry guitar mono signal and a rig processed stereo signal entirely in the digital domain as you can with Pro Tools LE in Pro Tools HD. You can only send your rig processed stereo signal digitally by AES/EBU or S/PDIF and then have to send your dry signal via analog. Am I wrong about this?

In any case. I'm interested in what the best way to configure Eleven Rack and the 96 IO would be. Right now I have AES/EBU input and outputs from my 96 IO. So what's the best way to get a dry, unprocessed signal in? Should I take Output 1 L or Output 2 R and go right into the 96 IO line input? Should I use a balanced cable? Please advise.

[TDigi]

Justin, you can use the option with the digital outputs to send both the dry guitar (L channel) and processed guitar (R channel) at the same time into your 96 I/O digital input. This is the user option "digital output" with the setting made for "Split In/Out". Set the Eleven Rack to be clocked "external" and the digital input to be AES/EBU (in the user option for Digital Clock/Input). Your Pro Tools session could have a mono track for recording the dry guitar signal on the AES/EBU left channel, and another mono track to record the processed guitar signal on the AES/EBU right channel. Then to re-amp, route the dry guitar track back into the Eleven Rack digital input (set the rig input user option to be the digital input L) and set the digital output user option to be "rig outputs" to hear just the processed signal on the digital L/R outputs when re-amping. Hope this helps!

-Toby Dunn
Avid/Digidesign Engineering Mgr for Eleven Rack

[Justin1524]

Thanks Toby -

That's an interesting way to do it, but not quite as elegant as the way demonstrated in your video using Pro Tools LE. I can see how recording mono guitar tracks live is preferred by many but I kind of like the idea of recording a stereo processed track and a dry mono guitar signal at the same time.

So assuming I'm fine with leaving the digital domain, I assume I could also take one of the analog outputs for my dry signal correct?

Also, I'm just curious, is there a good technical reason why the Pro Tools HD software can't recognize the Eleven Rack as an audio device and route audio via USB like it does in Pro Tools LE? This just seems like a feature that should be there.

Thanks!

[TDigi]

Right, you could take one of the "output to amp" outputs set to be at the rig input (user options "outputs to amp"), and connect it to an analog input on your 96 I/O to get the dry guitar signal (along with the stereo digital output carrying the full processed guitar rig). The Pro Tools HD architecture is not set up to easily integrate audio streams from USB or Firewire (the audio clocking is done thru the TDM system along with peripherals such as the 96 I/O, so it is somewhat difficult to use another audio driver to properly synchronize the audio streams coming in from a different source such as USB). Good luck, I hope you are enjoying the Eleven Rack!

-Toby

[sunburst79]

Not to hijack the thread but can you possibly post a comprehensive guide for using the 11Rack with the 002 and 003? Since we cant clock though AES.

[Chris Townsend]

I'd like to add one other point to Toby's comment about interfacing USB with TDM. I think the main gotcha when interfacing USB with TDM is achieving a reasonable latency. You'd need to have at least a couple buffering stages to go from USB to host and then host to TDM (probably 128 sample buffer size at best, since that's the minimum RTAS on aux tracks buffer size). The latency would be around 5 or 6 milliseconds in the theoretical best case I could imagine, but double that might be more realistic in the real world. By the way, Toby's the main guy who wrote the Pro Tools HD streaming engine, so he knows what he's talking about.

[Chris Townsend]

I've gotten the best results sending the dry guitar over S/PDIF or AES and the main stereo rig output via the analog main outs. If you reamp the dry signal with a high gain amp the analog noise floor might be noticeable (beyond what's already there from the guitar itself). Using digital, of course, adds no noise beyond what was there to begin with. With the M2 Lead, for instance, you could easily add more than 100dB gain, which is a very extreme scenario compared to any other normal recording situation I can think of. (100dB of gain will expose the noise floor of even the best converters in the world. On the other hand an electric guitar has quite a bit of noise to begin with, so it won't always matter.) In the case of the rig output, the guitar signal has already been gained up by the amp model and distortion pedals, so the noise floor of the analog outputs is negligible by comparison.

[Justin1524]

Thanks for the reply Chris, that thought didn't occur to me and it's a good one as I'm sure the main XLR outputs direct to the 96 IO would provide the best quality analog connection. I also appreciate the reply about USB latency, it's a shame though because surely that would add value to the product for HD users. Could I get you to comment on the electronics quality in general of the Eleven Rack. For example, how is the quality of the onboard mic preamp?

Hat's off on a great product and congrats to you and your team!