Delay Finder Measurement per IEC 61672-1

Measurement Accuracy for Delay

Delay measurement accuracy depends on the temporal resolution of the measurement system, which is governed by the sample rate and the quality of the impulse response capture.

Sample Rate and Resolution

• At 48 kHz: time resolution of 20.8 microseconds (about 7 mm distance resolution)
• At 96 kHz: time resolution of 10.4 microseconds (about 3.5 mm resolution)
• For speaker alignment, 48 kHz provides more than adequate resolution
• The practical limit is usually the accuracy of microphone placement, not sample rate

Frequency Response Impact

1. IEC 61672-1 frequency response tolerances affect the shape of the captured impulse
2. A system with poor low-frequency response may shift the apparent arrival time
3. Flat frequency response (Z-weighting) is required for accurate delay measurement
4. Apply no frequency weighting during delay measurement captures

Practical Accuracy

With IEC 61672-1 Class 2 compliant equipment at 48 kHz, delay measurement accuracy of plus or minus 0.1 ms (approximately 34 mm) is achievable. This is more than sufficient for live sound alignment where 1 ms accuracy is the typical target.

Common Mistakes

• Applying A-weighting during delay measurement, which affects the impulse shape
• Not accounting for system processing delay in the measurement chain
• Confusing sample-accurate delay with acoustic path accuracy

SonaVyx Approach

The delay finder in the SonaVyx transfer function operates at 48 kHz for sub-millisecond accuracy. Verify with the IR tool visual inspection. Check levels with the SPL meter. Use the RTA for spectral monitoring. Run AI diagnostics for alignment recommendations. See our learning modules for delay alignment tutorials.