Loudspeaker signals can be computed as virtual microphone signals with first-order directional patterns.

Evidence

First-order microphones have been available for decades, and we use as an example of how to compute signals for loudspeakers. The channels are matrixed that is, added together with different gains. Thus, each loudspeaker signal can be considered as a virtual microphone signal having first-order directional characteristics. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1859