Sound intensity is a vector describing the directional flow of sound energy.

Evidence

Sound intensity I [W/m2], as a physical measure, is defined as the sound power through a unit area, describing the flow of sound energy. Mathematically speaking, it is a vector - it has magnitude and direction, as will be further discussed in Section 14.4.7. Sound intensity level LI is defined as where the reference I0 = 1 · 10−12 [W/m2]. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 210

Categorization

• DEFINE: Defines sound intensity as vectorial flow of energy through a unit area, distinguishing it from scalar pressure.