Adding pads to Roland TD-12 and TD-20

Simplified Instructions for expanding the TD-20 (or TD-12) with an external trigger

• Make sure the pads plugged into your external trigger are set to channel 11.
• On the external trigger, set the head and rim notes to notes that are logical and easy to remember (ie head:40 and rim:41). Do this for boths pads (different notes for each of course).
• Press "Pattern" on the TD-20, then scroll up using the jogwheel until "Part" appears above the F2 key (if it isn't already there of course).
• Press F2 (Part), then F3 (Perc).
• Select the kit you want then press F5 to edit.

You are now in the "Percussion Set Edit" screen.

• Press F2 (edit).
• Go to "perc note" and select the note you assigned to the head or rim (depending on what you want to use).

You will need to do this for each head and rim of each pad you want to use. When you're done you can press List in the Percussion set edit screen to choose what instrument you wish to assign to your pads head or rim.

You can also change the settings for each instruments Volume, Panning, Pitch, Decay, Reverb, Chorus, and CC.

All editing for the pads plugged into your external trigger is now done on the TD-20 (except for trigger settings like sens. threshold etc.).

Source: VDrums.com Forum