Room impulse response measurements cannot be made with true perfect impulses from practical sources.

Evidence

The measurement of the impulse response of a room is an important case where perfect impulses are hard to generate. Unfortunately, a loudspeaker cannot produce impulses with high enough power. Balloon pops, hand claps, explosions, and electric sparks may be used to generate impulse-like sounds, all of which have some less than ideal properties, such as low repeatability and directional patterns deviating from the perfect, omnidirectional one. A high-power pulsed laser can also be used to generate impulses for acoustic measurements (see the example plot in Figure 2.20). Laserinduced pulses are repeatable and have an ideal omnidirectional pattern, although the cost of the device is, naturally, much higher, and using such devices is hazardous (Gómez Bolaños et al., 2013). — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 490

Categorization

• DEFINE: Explains why impulse response measurement is hard: real impulse sources are imperfect.
• ADDENDUM: Acoustic room-measurement techniques pair naturally with the sonic-worldbuilding themes of the articles about sound and place.