the MnM key tracking thingy is a sweet tool. you can apply any parameter to it and it will change it over 128 steps on the midi keyboard. HPF and LPF are default locked in parameters.
“The Key Tracking is connected to the note index from the last key pressed. For example, if C-1 was pressed, the key tracking value will be low, and if C-8 was pressed it would reach almost its maximum value.
There are two additional parameters on the Key Tracking controlling if the high pass and/or low pass filter should automatically track the pitch. See page 30 for more information on the filter.”
so the higher up you go on the keyboard the higher the HPF, so it’s shaving off lower frequencies.
turn it on or off to the taste of what sound you’re trying to achieve.