Too much me in the mix

[Filote]

Perhaps this will be helpful:  The software for my Zoom  UAC-8  (Mix Efx) gives me an on screen mixer which enables each of the 8  non-midi input channels with a circular knob-like control for the channel gain, which impacts directly upon the level sent to the output.  It also features slider controls for each channel's input, and I can eliminate the input in my JKZ headphone mix by running the slider down all the way (or on the slider grid, to -00).  This is helpful not only for JKZ, but for home recording as well, because  rolling down the input volume permits me to match the volume of already recorded tracks to which I am adding  an additional track. without impacting the output level for that track which becomes part of the recording, and can still be mixed up or down as necessary when perfecting the recorded mix.

Additionally, I can discretely choose and  change the output (Main Out includes input, but Line Out does not).  To sum up, try to figure out if your MOTU lets you regulate input volume down to no presence, or see if you have a choice of outputs that does not include present input.

Thank you for the suggestion, I appreciate it! Sounds like the equivalent software for MOTU is called CueMix.

In CueMix, there is a section called "Inputs" which have trim pots per channel, like your circular knobs; and in a section called "Mixes", there are volume faders, possibly like your sliders, 1 for each of the 8 outputs(I think they're for outs, but maybe for ins). I have them all turned down; yet I still get system volume per input channel when the trim pots are set to zero, and increase in volume when I turn them up.

The master volume knob, called "Monitor Level", behaves differently depending on what I set it to: If controlling Main Outs, all system sound is cut out when it's turned down. In this setting (Main Outs), the master volume knob on the hardware interface mirrors this behavior. But if Monitor Level in CueMix is controlling "Stereo", then system sound is audible (slightly louder than in Main Outs). In this setting (Stereo), the knob in the software and on the hardware do nothing to change volume up or down. The per-channel trim pots on the inputs behave the same in either mode (Main Outs or Stereo): the volume is still present when the trim is turned all the way to zero, but increases when turned up.

So I guess I don't understand the routing of CueMix, and only a little bit of it's relation$p to the hardware. There are settings in a mini-app called "MOTU Audio Setup", where you can assign things like Default Stereo in/out, Phones assign, Main Out assign, Return assign, etc; which may affect the routings, but it's a mystery to me. 

I wish the manual made more sense! It's a legacy product (Has worked since 2012), so I kind of doubt I'll get support from MOTU. I've posted in "MOTUNation" forum and searched the MOTU support website, hoping for some guidance. Thanks again!