How do you apply Key/Arp in the Matrix?

[pkskySynth]

What is a good demonstration for applying the Key/Arp output on the Matrix? I've tried omitting it from some of the presets and I am not hearing any difference.

[DrJustice]

Key tracking for the filter cutoff is the prime example. Some synths even have a dedicated key tracking knob for this because it's the most ubiquitous use of key tracking.

Other typical uses are key tracking for envelope times, e.g.to get shorter times for higher notes. With the uF, another good use of it is to apply key tracking to the oscillator parameters to control the timbre across the key range (that "timbre" as in the sound quality, not necessarily the Timbre knob).

Sometimes the key tracking can be subtle - it's often used precisely for quite subtle things. And sometimes it can be masked a bit and thus hard to "detect" directly - e.g. when velocity and key tracking both control the filter cutoff.

[pkskySynth]

I think I've come to understand that the effect of the Key/Arp is something best observed when considering the whole range of the keyboard. If you just go up and down a few keys, this is not a dramatic change when the whole range is not observed on the keyboard. The whole range is six octaves and if you range a destination from an Arp ranging over the the complete range, the effect is a little more observable.

I'm still a little confused about how you apply pitch as a destination when pitch is the first thing observed when pressing a key or applying an arp. Pitch as a destination from the LFO is much more dramatic.