Driving-point independence reveals isolated resonances, while overlap makes vibration patterns location-dependent

Evidence

One way to tell whether a given peak in power or admittance is an isolated resonance is to drive the system at the resonance frequency from different locations. As long as the locations are not too close to a nodal line of the resonant mode, an isolated resonance springs to life as the same pattern of vibration (mode) over the whole object, independent of the driving point. If, however, the modes are strongly overlapping, the combination of them that is generated varies from one driving point to the next. The pattern of vibration will depend on the driving point. — Eric J. Heller, Why You Hear What You Hear- An…, 1152

Categorization

• SEED: A diagnostic principle applicable anywhere resonance pools exist — acoustics, electrical networks, structures — worth an accessible piece on how listening position changes what a room sounds like.