Let me guess - you played a chord and while it was still ringing you reached down and twisted the Contour or Presence knobs and didn't notice much happening. The two tone controls are intended to be fine-tuning controls. We recommend setting them to noon and then just forgetting about them until you get to know the pedal and start wishing for slight tone modifications. But here's a good way to immediately hear what they are doing: For the Presence control, continuously play the high E and B string together while sweeping the control. You should hear the control sweeping through the upper presence frequencies. For the Contour control, continuously play the low E string with a slight bit of palm muting while turning the control. You'll hear how the bottom gets thicker or thinner. Another thing to try is set both to their extremes - Set the Presence at maximum and set Contour to minimum. Play a bit. Now set Presence to minimum and Contour to maximum. Play a bit more. Once you really get to know Groovy Wizard, I trust you'll appreciate the subtle fine-control you have over the frequencies.