When using ES-9 as mixer, controlled by Faderfox EC4, I have come across this little bonus:
The levels of ones different eurorack voices can vary quite a bit, and you do not have a gain per channel. But Faderfox’s Low and High values come in VERY handy.
As starting point, I limit all channels to 110, as I found that if they all go to max, the stereo out will clip. Then if there is a very loud voice, I go lower with that, and very soft voice can go to max.
Also I have found it really nice to set a Low (minimum) value, as the lowest values do extremely little. My standard Low value is now 15, and what it does is, that the min to max throw of the encoder is much more comfortable.
Oh, and one little EC4 tip: If you use more than one group, in settings, set encoder press to Group. This way you just have to press an encoder to go to another group, which is very sweet when one of your groups is your main mixer. Just a click, and you are back to your mixer.
And finally (but off topic): Having the EC4 totally opens up the FH-2. I just got one more FHX-8CV instead of my Divkid Ochd, and now I can “custom fit” the LFOs it produces to perfectly fit the destinations: Sync or no sync, bipolar or unipolar. And the FH-2 LFOs even have the wonderful ability to blend the waveforms, so you can have i.e. just a little bit of random flutter in your sine wave.
Between the ES-9 and FH-2, my Faderfox now controls about 100 parameters.