Delay Finder Measurement per IEC 60268-16

Delay Alignment for Speech Systems

Distributed PA systems use multiple speakers to cover large areas. Each zone must be delay-aligned so that listeners in overlap areas hear coherent speech rather than a confusing echo.

Zone Alignment Procedure

• Identify the primary coverage zone (usually the farthest from the signal source)
• Measure propagation delay from each speaker to the overlap zone with adjacent speakers
• Set electronic delay on each zone so all speakers in an overlap area arrive within 5 ms
• Maintain the Haas effect precedence (nearest speaker should arrive first)

Impact on STI

1. Delay misalignment beyond 10 ms creates audible echo that reduces perceived clarity
2. Comb filtering from misaligned speakers reduces per-band energy, lowering MTF
3. Properly aligned zones can improve STI by 0.05-0.10 compared to unaligned zones
4. Always verify STI after delay alignment to confirm improvement

EN 54-16 Requirements

For voice alarm systems, EN 54-16 requires STI above 0.50 at all listener positions. Delay alignment is often the difference between passing and failing this requirement in distributed systems.

Common Mistakes

• Setting delays based on distance calculation instead of actual measurement
• Not accounting for processing delay in the DSP chain
• Aligning each zone independently without checking overlap areas

SonaVyx Tools

Use the delay finder in the SonaVyx transfer function. Validate STI with the STI tool. Check levels with the SPL meter. View IRs with the IR tool. Get recommendations from the AI diagnostic. Follow the PA tuning workflow.