Coincident room modes create audible frequency peaks that extra resonances must balance

Evidence

Coincident modes are also another way of creating a perceptually noticeable frequency response peak, and the Bonello criteria do further stipulate that there should be no modal coincidence within a third-octave band unless there are at least three additional noncoincident resonances to balance the two that are coincident. As an example of the calculation of mode frequencies, let us calculate some for a typical living room. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1982

Categorization

• DEFINE: Clarifies ‘coincident modes’ as a distinct acoustical phenomenon with its own perceptual consequence.