@dengemann, from your previous line comments : 

> Thinking about it for one moment I would prefer preset fmin/mid/max for better comparability + code decluttering.

Hmm. I agree about better comparability, i.e. making fmin/mid/max preset will emphasize that we are really looking at slightly different values. On the other hand I like it how not using any presets would allow the user to experiment with the frequency ranges, so I like it this way, wdyt?