Loudspeakers

For as long as there have been loudspeakers there has been disagreement about how they should radiate sound. At one extreme are those who maintain that a loudspeaker should radiate over as narrow an angle as possible in order to minimise room contribution; at the other, those who believe that natural sound can only be obtained with omnidirectional loudspeakers that radiate sound with equal intensity to all points of the compass. Duevel attempts this by aiming both bass/mid unit and tweeter across a tapering conical radiator [see inset picture].

However, as it happens, neither ideal is easy to achieve, and most loudspeakers fall between the two stools. At low frequencies, where the wavelength of sound is long, sound diffracts around the cabinet and the radiation is omnidirectional. At higher frequencies, as wavelength shortens and the dimensions of the radiating diaphragm and cabinet become more significant, sound is progressively 'beamed' along the forward axis. In recent decades, nobody was a more ardent campaigner for wide speaker directivity than the late Siegfried Linkwitz [HFN Mar '16], who believed that the spectral content of the speaker's direct sound and that of early room reflections should match. But 'omni' speakers remain the exception rather than the rule. KH