The VH-12 Hi-hat's open/close range is called "Offset" in the TD-20. Offset is a crucial adjustment that should be done periodically so the VH-12 functions correctly. Use the following procedure to adjust the Hi-hat Offset:
1. Loosen the clutch of the top Hi-hat pad, then let it rest on the bottom hi hat.
2. Press and hold the KIT button and then press TRIGGER - the trigger button will flash momentarily. After a few seconds the trigger button will stop flashing, the Offset value will stabilize and the adjustment will be complete.
3. Press KIT to exit, then re-adjust and tighten the Hi-hat clutch.
Tip: If desired, you can further adjust and customize the Offset settings and other Hi-hat parameters to match your playing style. Refer to page 46 in the TD-20 manual.