Sound Delay Calculator
Calculate the time delay to apply to a delay speaker based on its distance from the main sound source and air temperature.
ft
°F
Speed of sound changes slightly with temperature
ms
Extra delay beyond travel time so listeners localize sound to the main source (10-20ms typical, per the Haas effect)
Delay Speaker Time Delay
63.15 ms
Pure travel time: 53.15 ms | Speed of sound: 1129 ft/s
How to Set Delay Speaker Timing
In a live sound system, delay speakers extend coverage to areas far from the main speakers. Because sound travels at a finite speed (about 1,125 ft/s or 343 m/s at room temperature), listeners near the delay speaker would otherwise hear it before the sound from the distant main speakers arrives, making the source sound like it's coming from the wrong place and causing comb-filtering/echo issues. The fix is to electronically delay the signal to the delay speaker so both sounds arrive together.
Speed of sound increases slightly with temperature, so this calculator adjusts it based on the air temperature you enter. Many live sound engineers also add a small extra offset (commonly 10-20ms) beyond the pure travel-time delay — this exploits the "Haas effect" (precedence effect), where the human ear localizes a sound to whichever source it hears first, as long as a second copy arrives within about 30ms. Adding a bit of extra delay helps the audience perceive all sound as coming from the main stage, even when standing near a delay speaker.
Example
A delay speaker positioned 60 ft from the main speakers, at 70°F, needs a pure travel-time delay of about 53.6ms. Adding a typical 10ms precedence offset brings the total delay setting to roughly 63.6ms.
Common Use Cases
- Setting delay times for delay/fill speakers at concerts, houses of worship, or large venues.
- Time-aligning subwoofers or under-balcony speakers with the main PA.
- Planning a distributed sound system across a large outdoor venue.
FAQs
Why does temperature affect the delay time?
Sound travels faster through warmer air because warmer air molecules move faster and transmit pressure waves more quickly. The difference is small over typical room-temperature ranges, but can matter for precise time-alignment over longer distances or in outdoor venues with big temperature swings.
Do I always need to add the extra precedence offset?
No — some engineers set delay speakers to the exact calculated travel-time delay with no offset, especially for pure intelligibility/fill applications. The extra 10-20ms offset is a common practice for helping the audience perceive the sound as coming from the main stage rather than the nearby delay speaker; feel free to set it to 0 if you prefer an exact time-aligned setup.
Does humidity affect the speed of sound too?
Slightly, but the effect is much smaller than temperature for typical live-sound purposes, so this calculator only adjusts for temperature to keep things simple and practical.