Keylab MkII 61 Keyboard Velocity curve explanation:

[brianbrook]

Velocity Curve: Three settings are available: Linear (Lin), Logarithmic (Log), or
Exponential (Exp)

The default is set to Linear, if I want to change this so when I hit the keys harder I can get more output which setting should it be? Other words I can't find any info on Log or Exponential in the manual?

[mscman]

All three modes you describe have the effect of making the sound louder the harder you hit the keys. The difference is how much harder you have to press them to make it really loud/soft.

Linear mode means that it's a 1:1 ratio between how hard you hit the key and how loud it is.

An exponential curve (exp mode) means that the curve gradually gets steeper. This has the effect of the overall sound being fairly soft unless you're really pounding on the keys.

A logarithmic curve (log mode) means the curve starts very steep, then gradually flattens out. This means that you don't have to press very hard to get a loud sound, but it doesn't get much louder than that as you hit harder.

They give these different options because different players have personal preferences over how the velocity curves affect their expressiveness while playing. I would suggest trying all three with different sounds and find what works best for you.