The A/D INPUT has a GAIN Control on the front panel this is to match the input sensitivity to the output level of the Source. If the Source is a microphone expect to have to increase this GAIN stage significantly. When the Source is an electronic Keyboard, as you are using, you will need a only a moderate amount of assistance from this GAIN. The Gain setting is critical and is set with the front panel Knob.

The VOLUME parameter found within each Performance allows you to use as much of the properly gain staged signal to match the level of the MODX.

You can have the MODX memorize a Volume settings for the input device —Or— you can globally bypass this so that your settings for the Audio Input does not change per Performance. Below is additional info on Gain Staging and the Global A/D setting:

Please see this post for the details on Gain Staging: MODX A/D INPUT Headroom

Extra Credit: A/D Input signal can be mixed as apart of the Motion Control Synthesis Engine. An external synth or module under MODX MIDI control that is also routed through the AD Input can become assigned MODX Insertion Effects, it can be routed to the System Effects, it’s Volume can be controlled by the Super Knob... it becomes a KBD CTRL Part with many of the features and benefits of internal MODX sounds. This is why the VOLUME you see within the Performance is there... that is not the INPUT GAIN... Input gain is set so that maximum will not distort... this PART VOLUME is the musical balance. It’s maximum will never distort because you’ve set the Gain properly.

Also available if NOT using the Motion Control Synthesis Engine, you Set the A/D INPUT so that one setting is “global” — this will apply across all Performances. Here’s how Setup the GLOBAL A/D INPUT:

On the HOME screen tap the “FX” on the very top line of the screen. Here you will find the GLOBAL A/D parameter.
When On, the setting you make for the AD INPUT will be maintained through all Performances.

Global A/D
Determines whether the volume for the A/D Part changes when you switch the Performances.
When this parameter is ON, the volume for the A/D Part stays the same, and other parameters related to the A/D Part do not change. When set to OFF, the volume changes according to the volume set in each Performance, and other parameters related to the A/D Part change accordingly.
The Global A/D settings are not stored.
Settings: Off, On

Thanks for the reply, Bad Mister. I have read about the Gain, Volume, and post-eq output db offset for the AD signal. I believe I have correctly 'gain-staged' my Nord signal coming into the MODX. What I'm trying to achieve is a constant "perceived volume" from the Nord irrespective of whatever Performance I have selected on the MODX, (i.e. a lot of the time I'm just playing the NORD and don't care about the settings on the MODX). So.... what I'm trying to achieve requires that the Performance AD Audio I/O "Volume" setting has to be the SAME for any Performance that might be current in the MODX. (Don't want any routing thru the MODX effects for this Still not sure I'm asking the right question; I can probably figure this out with some testing. Anyway, thanks again for the input.

On the HOME screen tap the “FX” on the very top line of the screen. Here you will find the GLOBAL A/D parameter.
When On, the setting you make for the AD INPUT will be maintained through all Performances.

Global A/D
Determines whether the volume for the A/D Part changes when you switch the Performances.
When this parameter is ON, the volume for the A/D Part stays the same, and other parameters related to the A/D Part do not change. When set to OFF, the volume changes according to the volume set in each Performance, and other parameters related to the A/D Part change accordingly.
The Global A/D settings are not stored.
Settings: Off, On

Ah, excellent; that's what I was looking for - a global setting. Thanks again!!