What counts as a phase anomaly? Does the phase have to be perfectly flat, or just relatively smooth, free from abrupt shifts?As an acoustical engineer, I would argue that relative phase is a more important measurement over frequency response. Both acoustical and electrical phase anomalies are more perceptual to sound quality attributes, effecting amplitude, spatiality, and timbre. Fairly poor frequency response can sound good or bad, but poor relative phase never sounds good.