GR-20: Selecting Guitar or Bass Mode.
If your GR-20 is updated to the latest version, it's possible to use it with a bass guitar equipped with the Roland GK-3B Pickup. To obtain the best tracking results with this application, you must select "Bass mode" in the GR-20. Use the following steps to select Guitar or Bass mode:
Note: The Factory default for this mode in the GR-20 is set for guitar.
1. Power on while holding the SENS button.
2. Release SENS, and then turn the VALUE dial to select the desired setting; Choose "Gt" when using Guitar. Choose "Bg" when using bass guitar.
3. Press EXIT to save the new setting.
Tip: After choosing the correct mode, be sure to adjust the sensitivity for each string.