Field Story
Echo Canyon: When Delay Towers Fight Each Other
A 15,000-seat sports arena installed delay towers at three distances from the stage. Audience members near the second tower heard a distinct echo because the delay was set 28 ms too short. Transfer function coherence dropped to 0.3 in the overlap zone. After measuring propagation delay with the delay finder tool and correcting each tower to within 1 ms, coherence improved to 0.85 and the echo disappeared.
Sports ArenaDelay Finder Measurement per ANSI S1.4
TL;DR
ANSI S1.4 measurement chain specifications affect the accuracy of delay finding through sample rate, detector response, and frequency bandwidth. The delay finder extracts propagation timing from the impulse response, and the quality of this extraction depends on the temporal and spectral characteristics of the measurement system. Understanding ANSI S1.4 specifications helps you evaluate whether your measurement chain provides adequate time resolution for the alignment accuracy required by your application. SonaVyx operates at 48 kHz with 24-bit resolution, providing timing accuracy well within ANSI S1.4 Class 2 requirements.
ANSI S1.4 and Timing Accuracy
The delay finder depends on the measurement system accurately capturing the time-domain signal. ANSI S1.4 specifications define the performance envelope within which this capture occurs.
Time Resolution
- ANSI S1.4 does not specify a sample rate, but the digital implementation determines time resolution
- At 48 kHz: each sample represents 20.8 microseconds
- Sub-sample interpolation can improve resolution to approximately 5 microseconds
- This translates to approximately 2 mm spatial resolution
Bandwidth and Impulse Shape
- The system bandwidth determines the sharpness of the impulse peak
- Wider bandwidth produces sharper peaks and more accurate delay detection
- ANSI S1.4 frequency response tolerances affect the impulse shape slightly
- For delay measurement, the effect is negligible within Class 2 tolerances
Detector Bypass
Delay measurement requires access to the raw time-domain signal, not the time-weighted detector output. ANSI S1.4 detector specifications (Fast, Slow) are not relevant for delay finding, which operates on the unprocessed impulse response.
Common Mistakes
- Assuming that the sample rate limits practical delay accuracy (placement precision usually dominates)
- Using a weighted signal for delay measurement instead of linear/Z
- Not calibrating the system delay (microphone, cable, ADC latency)
SonaVyx Approach
The delay finder in the SonaVyx transfer function uses 48 kHz capture with sub-sample interpolation. Verify timing with the IR tool. Check levels with the SPL meter. Use the RTA for spectral context. Run AI diagnostics for alignment assessment. See our learning modules for delay alignment tutorials.
Standard Reference
ANSI S1.4:
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Last updated: March 19, 2026