• Registered: 2021-09-17
  • Posts: 13

Topic: Send FX AD/DA Conversion and Loopback Trick

I am trying to set up my studio with the UCX II and have two questions.

1. I have some hardware send effects and want to set up a chain with my UCX II and a Samson S-Patch Plus patchbay. I just watched these videos by RME: https://youtu.be/ApwZyRTTmc0
https://youtu.be/jlRQbV2LcFg

Can you tell me why anyone would record that way instead of splitting the signal before recording it with something like a patchbay?
If we record like suggested in the videos you effectively are converting the analog signal to digital and back to analog just to record and convert it again? Or do RME interfaces allow analog pass-through?

2. While trying to simplify things I came across this video: https://youtu.be/l6XCiyVfnUk?t=235

If I use the suggested trick (loopback on the SPIDIF output and all channels turned up, even if only one is currently used) will I introduce noise? In theory, it sounds messy to me. I am assuming that all the channels that are turned up and are connected to hardware that is not in use could introduce some kind of noise to the recording. Is anyone recording this way and can share some experiences?

Thanks for your help!

2 Reply by ramses (edited by ramses 2024-03-03 08:32:17)

  • ramses
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  • Registered: 2012-10-14
  • Posts: 12,112

Re: Send FX AD/DA Conversion and Loopback Trick

I am using two Lexicon PCM as external FX.
In Cubase easy to implement as an external effect.

You only need to support this a little by configuring the proper routing.
As an additional routing task in TotalMix you only have to take care to route audio from the application
(from SW playbacks) to the HW outputs where the external FX is connected to.

Then Cubase can perform a ping to calculate the latency for the external plugin. If you have a FX with Delay or Reverb then you need to set the FX section to "bypass", otherwise you get too high latency values.

I am using in my guitar setup the UFX III as
- parallel effect loop for two Marshall's (stereo setup, because of the Lexicon PCMs working to 98% only in stereo)
and
- to assign the two Lexicons (PCM 81 and 91) either for Guitar or DAW or for both (PCM81 for guitar, PCM91 for DAW) by TM FX routing

Once the routing is fine and the definition of the two external FX in the DAW, it is super practical, that you can use the external FX like a VST in the DAW ... you can use it either as send or as insert.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • ramses
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Re: Send FX AD/DA Conversion and Loopback Trick

Ah, I found it now ...

The implementation in Cubase and TM FX routing, see here:
https://forum.rme-audio.de/viewtopic.ph … 00#p192400

As an option: clean-up routing in TM FX and to use only the required flows.
This makes checking of routing easier … Esp. if you want to use the matrix view for that purpose.
Not really required, but a nice and useful exercise …
https://forum.rme-audio.de/viewtopic.php?id=36025

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • Registered: 2021-09-17
  • Posts: 13

Re: Send FX AD/DA Conversion and Loopback Trick

Thanks for your response but it is not the answer to my questions. In short:

1. Is splitting the signal before recording for external effects not better than converting it four times?

2. Do you introduce noise to a recording if the inputs that are not in use but connected to instruments are active?

  • ramses
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  • Registered: 2012-10-14
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Re: Send FX AD/DA Conversion and Loopback Trick

To be honest, I didn't understand your use case exactly for lack of a simple drawing.
I hoped that my information would at least help you a little further as far as the integration of external FX is concerned.
A small diagram would probably have helped to make the whole thing easier to understand in terms of audio flows.
And I don't always have the time or inclination to scribble something down myself.
You'll just have to wait for people who work in a similar way and understand what you mean directly.

to 2. I am muting not used analog and instr inputs. The metering or Digicheck will show you any noise.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • Registered: 2016-06-14
  • Posts: 990

Re: Send FX AD/DA Conversion and Loopback Trick

Hi

For using more than one hardware effect on the same original (dry) signal, you simply can make an old school analog chain. So going directly from efx nr.1 output to input of efx nr.2 and so on. The last efx unit output you connect to the audio interface input.

Yes, when using a particular analog output for efx send, you have to be very careful with the TotalMix routing. For example mic inputs without something connected and with open gain can cause lots of hiss! So make always sure to have closed all unused input and software playback channels on this specific submix.

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