Field Story
Subwoofer Phase War at the Amphitheater
An outdoor amphitheater deployed four subwoofers in a line array, but seats in rows 12-18 heard almost no bass below 120 Hz. Transfer function measurement revealed a 22 dB null at the crossover frequency caused by phase cancellation between the main tops and subs. Correcting the sub delay by 4.2 ms and flipping polarity on the outer pair restored flat response across all seats.
Outdoor AmphitheaterSpectrum Analyzer Measurement per AES-2id
TL;DR
The spectrum analyzer is a fundamental tool in AES-2id system alignment, providing real-time visual feedback of the system frequency response. During the alignment process, the RTA shows the combined effect of the electronics, speakers, and room on the reproduced spectrum. AES-2id practitioners use the spectrum analyzer for gain structure verification, EQ adjustment monitoring, and coverage uniformity assessment. SonaVyx RTA mode with configurable smoothing (1/1 to 1/24 octave) and multiple averaging modes gives you the real-time feedback needed for efficient system tuning per AES-2id methodology.
RTA in AES-2id Alignment
The real-time analyzer is your primary visual feedback tool during AES-2id system alignment. While the transfer function provides more detailed and accurate data, the RTA gives immediate visual confirmation during hands-on adjustments.
Gain Structure Verification
- Send pink noise at nominal level through the system
- The RTA should show approximately flat response (within 3 dB per octave band)
- Identify any gross deviations that indicate hardware problems before detailed tuning
- Compare the RTA at multiple positions to assess coverage uniformity
EQ Monitoring
- Display the RTA while making EQ adjustments on the processing
- Use 1/3-octave smoothing for parametric EQ adjustment visualization
- Switch to 1/12 or 1/24 octave to see the effect of narrow notch filters
- Compare against a stored reference trace to track changes
Smoothing Selection
Different smoothing levels serve different purposes during alignment. Use 1/1 octave for overall tonal balance, 1/3 octave for parametric EQ, and 1/12 to 1/24 octave for identifying room modes and feedback frequencies.
Common Mistakes
- Tuning the system based on RTA alone without using transfer function for precise analysis
- Using too fine a smoothing setting, chasing room modes with EQ
- Not accounting for the logarithmic nature of pink noise energy distribution
- Measuring too close to the speaker where direct field dominates
SonaVyx Tools
Use the SonaVyx RTA/spectrum analyzer for real-time monitoring. Switch to the transfer function for precise alignment measurements. Check levels with the SPL meter. Identify problems with the problem detector. Get AI-powered EQ recommendations from the diagnostic engine. Follow the PA tuning workflow for structured alignment.
Standard Reference
AES-2id:
Try It Now
Open this measurement tool in your browser — free, no download required.
Last updated: March 19, 2026