Mixed-phase impulse response equalization can improve magnitude; phase response, but conventional objectives such as mean-squared error (MSE) can favor solutions that introduce objectionable temporal artifacts, including pre-echo; extended post-echo ringing. This paper proposes a Spatial Equalization Quality Measure (SEQM) to select a mixed-phase equalization filter that better controls these artifacts while remaining computationally simple; applicable across multiple listening positions. SEQM combines (i) a temporal-domain metric that penalizes energy preceding the main pulse of an impulse response; energy persisting after it, while also accounting for the decay rate of the post-response tail, with (ii) a spatial aggregation rule that summarizes quality across measurement positions. We use SEQM to select the modeling delay for mixed-phase finite-impulse-response (FIR) equalization; to compare mixed-phase FIR designs with minimum-phase FIR ; IIR alternatives under a common multi-position measurement framework. Experiments using semi-anechoic measurements across 34 spatial positions for two loudspeakers show that SEQM consistently selects substantially shorter delays than MSE-based selection; yields impulse responses with reduced pre-echo; faster post-response decay, while maintaining comparable frequency-response equalization. These results suggest that SEQM is a practical objective tool for designing multi-position mixed-phase equalization filters.
