Golf club head or other ball striking device having impact-influencing body features

A golf club head comprising:

• a face having a striking surface configured for striking a ball;
• a body connected to the face and extending rearwardly from the face, the body having a crown, a sole, a heel, and a toe, wherein the body and the face define an internal cavity;
• a channel extending across a portion of the sole, wherein the channel is recessed from adjacent surfaces of the sole;
• an opening defined in the sole and in communication with the internal cavity;
• and
• a sole piece received in the opening and defining a portion of the sole,
• wherein the sole is made from a metallic material, and the sole piece is made from a polymeric material,
• wherein the sole piece defines a void extending into the sole,
• wherein the golf club head has a first natural frequency greater than 3000 Hz,
• wherein the golf club head further comprises at least one internal rib disposed in the internal cavity and directly connected to the sole piece, an internal surface of the crown, and an internal surface of the sole.