Microphone directivity shapes how reverberant a convolved signal sounds

Evidence

If the impulse response of a target room is readily available, the most faithful reverberation method is to convolve the input signal with the impulse response. The result corresponds to the imaginary case where the input signal to be reverberated is applied to the loudspeaker in the measurement room and the listener listens to the signal recorded using the microphone used in the measurement. Note that the directional responses of the microphone and the sound source used in the measurement affect the result. For example, the reverberation effect will be considerably different if the directivity of the microphone is changed. An omnidirectional microphone captures the reverberation from all directions equally, while a directional microphone facing towards the source significantly suppresses sound arriving from the reverberant field. If these responses are used in convolving reverberators, the omnidirectional response will be perceived as much more reverberant than the directional response. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1957

Categorization

• DEFINE: Clarifies why impulse-response-based convolution captures a specific mic/source pair rather than a neutral room.
• XREF: connects to: Microphone configuration determines whether sound origin location can be recovered — Almo Farina, Soundscape Ecology: Principles,…, 1978