In this post, I had already described my experience how positive the complete new setup or optimization of my TM FX setup went: https://forum.rme-audio.de/viewtopic.php?id=36025

Here I would like to add useful information how to best integrate external effects units so that they can be used both for the DAW as external FX or for a guitar amp.

The routings for the different use cases can be stored and recalled quickly and user-friendly in TotalMix FX Snapshots.

My main “Use Cases” for the Lexicons are as follows:
#1 – PCM81 for guitar because of modulation effects
#2 – PCM91 for mixing/mastering, but also for guitar
#3 – Both Lexicons (PCM81+91) for Cubase as external FX

For each use case, you will find a screenshot of TotalMix FX in “matrix view”. There you have the complete routing overview of all hardware outputs (aka “Submixes”) of a particular snapshot. In the screenshot, I documented the essential routing settings for the respective “Use Case”.

Here you can see now clearly, how few changes are only necessary to achieve the desired functionality.

This small documentation also answers the questions of many users, how to integrate external FX best. You just have to adjust the routing accordingly.

How to route the external FX for the DAW is shown in Use Case #3. The last screenshot shows the setup of the external FX in my DAC (Cubase 12 Pro in this case). DAWs like Cubase can then determine the latency due to the external effect, so there is then full latency compensation for the external FX so that all tracks are time-synchronized.

In conclusion, I can simply say that my cleanup efforts were fully worth it. The Matrix View now offers me a great overview because I first removed all routings and then implemented only the required routings.

Matrix View has become very helpful for debugging. You can see certain things faster than in the mixer view.
You can't say one is better than the other, both views complement each other in a nice way.

Use Case 1 – PCM81 for Amp / PCM91 for DAW

Use Case 2 – PCM91 for Amp

Use Case 3 – Both PCM's as external FX for DAW

Cubase 12 Pro - Audio Connections - External FX

Note: the latency for external FX is quite high because I forgot to set FX to 100% dry during Cubase latency measuring. The current values are 1.5 and 2.02ms for PCM81 and PCM91.

Finally, “matrix view” & “only required routings” made it possible to check and document routings efficiently.