Phase Analysis per AES-2id

TL;DR

Phase analysis is the heart of AES-2id system alignment. The phase response of the transfer function reveals timing relationships between frequency components that determine whether speakers sum constructively or destructively at the crossover. AES-2id practitioners use phase to align subwoofers with mains, match multiple speaker zones, and optimize crossover filter settings. SonaVyx transfer function displays unwrapped phase with group delay, providing the information needed to achieve the tight phase matching (within 45 degrees through the crossover region) that separates professional alignment from amateur EQ adjustments.

Phase in System Alignment

Phase analysis reveals the timing behavior of the system across frequency. While magnitude shows how loud each frequency is, phase shows when each frequency arrives. Both must be optimized for a well-tuned system.

Crossover Alignment

At the crossover frequency, both drivers must be in phase for constructive summation
Phase difference greater than 90 degrees causes destructive interference (dip at crossover)
Target: less than 45 degrees phase difference through the crossover region
Use delay and polarity adjustments to achieve phase alignment

Sub-Main Alignment

Measure phase of subwoofer system alone at the crossover frequency
Measure phase of main system alone at the same frequency
Adjust sub delay until both phases match within 30 degrees at crossover
Verify with combined measurement showing constructive summation

Group Delay

Group delay is the negative derivative of phase with respect to frequency. Constant group delay means all frequencies arrive at the same time. Large group delay variations indicate timing problems that cause smeared transient response.

Common Mistakes

Ignoring phase and focusing only on magnitude response
Using delay to fix a polarity problem (or vice versa)
Not measuring phase at the crossover frequency specifically
Confusing wrapped and unwrapped phase displays

SonaVyx Tools

Use phase analysis in the SonaVyx transfer function. Check polarity with the problem detector. Monitor levels with the SPL meter. View impulse timing with the IR tool. Get AI alignment recommendations from the diagnostic engine. Follow the PA tuning workflow.

Subwoofer Phase War at the Amphitheater