Phase Alignment

In any system with multiple speakers covering different frequency ranges (subwoofers, mains, fills, delays), the acoustic outputs must arrive at the listener position in a time relationship that produces constructive interference at critical frequencies — particularly the crossover points where two speakers share coverage. At a crossover frequency of 100 Hz (wavelength = 3.43 m), a 5 ms timing error between sub and main corresponds to 1.72 m of path difference — half a wavelength — producing complete cancellation at 100 Hz. Even 2 ms of misalignment at 100 Hz causes 72° of phase offset and noticeable comb filtering through the crossover region. The alignment procedure uses a transfer function measurement between the reference signal and the microphone. Each speaker is measured individually to determine its arrival time and frequency-dependent phase behavior. Delay is then added to the closer speaker (or earlier-arriving signal path) to synchronize arrivals at the target crossover frequency. Phase alignment is frequency-specific. Two speakers may be perfectly aligned at 1 kHz but misaligned at 100 Hz due to different propagation speeds through their respective crossover filters. Crossover filters (Butterworth, Linkwitz-Riley, Bessel) each have characteristic phase rotation that must be accounted for. A 4th-order Linkwitz-Riley crossover produces 360° of phase rotation at crossover — meaning both drivers are back in phase despite the steep filter slopes. The measurement point matters critically. Phase alignment at one position may not hold at other positions because different path lengths create different arrival times. The standard practice is to align at the most critical listener position (usually front-of-house mixing position or geometric center of the audience) and accept degraded alignment at other positions. SonaVyx displays phase response in transfer function mode with coherence-weighted confidence, enabling precise alignment at the crossover frequency.