Abstract: This disclosure is directed to couplers which significantly reduce the production of noise when disconnected from a mating coupler, thus addressing a significant occupational safety problem in the field of compressed air couplings. Accordingly, one aspect of the disclosure provides a coupler which may be used to connect/disconnect an air hose subjected to high air pressure while suppressing or dampening the noise typically produced upon disconnecting the coupler. In some examples, a coupler is provided with a valve having axial passageways that facilitate the relatively free flow of air during normal operation that become partially occluded upon an action disconnecting the coupler to significantly reduce sound levels.