Loudspeaker and Headphone Handbook, 3rd Edition

 

14	Headphones
	C. A. Poldy

14.1 Introduction

The first difference that comes to mind when comparing how loudspeakers and headphones produce a sound signal at the ear is that in one case the ear is immersed in a propagating sound field, and in the other it registers the SPL (sound pressure level) in a leaky pressure chamber. ‘Since the ear drum is essentially a pressure detector, pressure gradient, particle velocity and other effects do not influence the final sound image.’ This is a daring claim, since much research has been performed dealing precisely with this point, for example such elusive phenomena as ‘the missing 6 dB between LS (loudspeaker) and HP (headphone) listening’, and whether bone conduction plays a role in hearing external ...