It's possible to adjust the volume level for each pad in a kit of the TD-4KP. Here's how.

1. Choose a desired kit to edit.

2. Press the MENU button.

3. Press SEL down to select "2 MIXER.".

4. Press OK.

5. Hit a pad that you'd like to change the volume of.

6. Turn the +/- dial to adjust the volume.

7. Repeat Steps 5 and 6 for any remaining pads if desired. 

8. When you're finished, press MENU. The new setting is saved in the kit automatically