I've picked up a new stereo cabinet and am concerned about ventilation.

Cabinet is approx 3' tall x 2' wide x 2 ' deep. Has a glass door at the front and two holes for wires at bottom (in the back).

Contains an RR2150 (at top), CD multi-changer (middle), and Apple Airport, surge protection, wires (bottom).

I've noticed that the ~3" gap above the RR2150 does get noticeably warmer than ambient if left running with the glass door closed.

I'm thinking of drilling a hole (or two) for ventilation at the top (in the back). Maybe adding a fan in there to move the air around.

Wondering if anyone had any guidance about their own cabinets and/or ventilation?

Thx.