Combined quasi-anechoic and in-room equalization of loudspeaker responses

This paper presents a combined approach to loudspeaker/room response equalization based on simple inroom measurements. In the first step, the anechoic response of the loudspeaker, which mostly determines localization and timbre perception, is equalized with a low-order non-minimum-phase equalizer. This is actually done using the gated in-room response, which means that the equalization is incorrect at low frequencies where the gate time is shorter than the anechoic impulse response. In the second step a fractionaloctave resolution minimum-phase equalizer is designed for correcting the low-frequency part of the response, based on the in-room response pre-equalized with the quasi-anechoic equalizer. This second step, in addition to correcting the room response, automatically compensates the low-frequency errors made in the quasianechoic equalizer design when using gated responses.