Matched filter array (MFA) processing uses impulse responses (IRs) in its algorithm to provide high signal-to-noise and 3-D spatial selectivity. The spatial and frequency selectivity of the MFA is shown for an array of eight randomly placed microphones in a 0.7-s reverberant conference room. The IRs were measured using nine averages of a 16<th>383 sample maximum length sequence at a 16-kHz sample rate from a loudspeaker representing on- and off-focus conditions. The MFA response was formed offline by convolution of the time-reversed IR with an IR representing the incoming source position to each microphone, with a final summation over the array. Truncation of the impulse responses is applied to remove anticausal echo. The spatial selectivity of this array is on the order of 25 cm from the focus. The influence of the room transfer function on the frequency response of the MFA is shown. It is seen that the frequency focal volume immediately degrades off-focus for the high frequencies first and that the off-focus condition causes a time-delay in the array response. The influence of individual matched filters versus the array response on the spatial selectivity is explained. [Work supported by Intel and Texas Instruments.]