Frequency, phase, and impulse responses are mathematically interchangeable descriptions of linear behavior.

Evidence

Performance measurements of audio devices fall into two general categories: linear and non-linear behavior. Linear characteristics are those that do not change with sound/signal level: magnitude vs. frequency (a.k.a. frequency response) and phase vs. frequency (a.k.a. phase response). These two can be mathematically transformed into the time-domain impulse response (a.k.a. transient response). The data are interchangeable. — Toole, Floyd E, Sound reproduction- the acoustics and…, 103

Categorization

• DEFINE: Establishes the linear/non-linear distinction central to all loudspeaker measurement discussed later.