Abstract: Duplex pneumatic valves are provided for use in regulating the flow of air from a wind chest through an orifice to a pneumatic work chamber such as an organ pipe. The duplex valves comprise a principle valve having a rear surface and a seating surface seatable on the orifice and at least one venting channel in the principle valve means communicating with each of the seating and rear surfaces, thereof, and an initial valve having a seating surface seatable on the venting channel at the rear surface of the principle valve means. Methods for controlling the flow of air into, for example, an organ pipe are also disclosed employing the duplex pneumatic valves of this invention.