12.5 Localisation of sound in the vertical plane
Much of our ability to localise sound in the vertical plane is due to the shape of the outer ear, in particular the pinna. The pinnae provide a monaural cue to localisation. The bumps and ridges on the pinnae produce reflections, and delays between the direct path and the reflected path make vertical localisation possible. Vertical localisation is seriously impaired if the convolutions of the pinnae are covered.