PD-7, PD-9: Differences between the PD-7 and PD-9 April 12, 2023 08:47 Updated Follow The only difference is the size. PD-9 is 10" diameter and PD-7 is 7.5". Another difference, not affecting performance, is the texture of the pad. Related articles PD-9: Specifications TD-02, TD-07, TD-17, TD-27, TD-50, TD-50X: Pad Compatibility Chart PD-7: Specifications SPD-SX PRO: Which external pads and pedals are supported? BT-1: Selecting the Pad/Trigger Type for the input within the V-Drums module (BT-1 SENS)