Dipole surrounds only worked for one row of listening positions

Evidence

The large difference between the direct sound and the listening window curves indicates that the null is very narrow, meaning so it is effective only for a single row of listeners with their heads in a line 90° perpendicular to the side wall. These loudspeakers must be located at ±90° to that row of listeners. Much of the sound energy that is radiated reflects off the front and rear walls of the room, which are poor locations for enhancing spatial effects, see Figure 7.4(b). Small acoustically damped domestic rooms cannot support a diffuse sound field of any magnitude so that is not a factor. — Toole, Floyd E, Sound reproduction- the acoustics and…, 829

Categorization

• XREF: Connects to the broader theme in this book and the reader’s ‘One Square Inch’ work about sound fields in small rooms - diffusion requires large acoustic spaces.