Overview

This paper defines several speaker-array systems based on a sampling-theory approach:

• Planewave-Based Angle Panning (PBAP) consists of at least one linear speaker array implementing an approximation to Far-Field Wave Field Synthesis (FFWFS).

• Polygonal PBAP (PPBAP) uses multiple PBAP arrays to define an interior acoustic space which is preferably polygonal in the 2D case. Thus, multiple line arrays are combined to form a polygonal listening area, such as a square, rectangle, octagon, etc.

• Truncated Polygonal PBAP is a variation on PPBAP which trims each line array down to the polygon side it includes. In the limit of many polygon sides, a circular array is obtained, giving the simplest form of Vector-Base Amplitude-Panning (VBAP) (Pulkki, 2001,1997) in which only one speaker (the one closest to the desired angle) emits each source.

• Huygens Array (HA) is a generalized approach allowing sources and speakers/microphones to be placed anywhere on the listener-side of the source(s). In this case, sampling-based insights provide guidance for what to expect, and how to avoid artifacts by maintaining a valid (nonuniform) sampling grid.

• Various straightforward extensions to 3D are discussed.

• Multiband arrays and integrations with VBAP, stereo, and subwoofers are discussed.

When conditions for sample-based reconstruction are not met, we transition as gracefully as possible to some form of Vector Base Amplitude Panning (VBAP) (Pulkki, 2001).

A benefit of extending VBAP to PBAP is providing a larger ``sweet spot,'' since the quasi spherical waves emanating from VBAP speakers become upgraded to approximations of sampled plane waves in PBAP, and plane waves are the same for all listeners to within a delay. In other words, it is well known that point sources, such as ideal speakers used for ordinary stereo, produce listening levels that are sensitive to listener proximity, while a soundfield composed of a plane wave from each far-field source gives a constant level versus position for each source.