Bipole but not dipole designs give surround channels needed coverage

Evidence

The challenge is to find loudspeakers with the necessary horizontal dispersion to cover the audience. In general, this is satisfied by bipole—bidirectional in-phase—designs. There are other variants with clever names, but most amount to no more than loudspeakers having very wide dispersion—a good thing in this case. Dipoles should be avoided. — Toole, Floyd E, Sound reproduction- the acoustics and…, 807

Categorization

• DEFINE: Draws the working distinction between bipole (bidirectional in-phase) and dipole designs for surround use.