Sound Delay Calculator
Speaker delay timing from distance for outdoor performances.
About this calculator
This calculator sets the electronic delay time for a delay speaker so that a distributed sound system stays time-aligned with a venue's main PA, relying on the Haas (precedence) effect — listeners perceive sound as coming from whichever source arrives first, so as long as the delay speaker's output arrives a few milliseconds after the main PA's direct sound, the ear still localizes to the main PA even though the delay speaker is physically closer and louder. It first computes the speed of sound from your air temperature using the standard approximation 331.3 + 0.606 times temperature in °C — warmer air genuinely carries sound faster, which matters for large outdoor rigs where a few degrees can shift timing by measurable milliseconds. From there it works out travel time for the main PA's sound to reach the listener near the delay speaker, and travel time for the delay speaker's own sound to reach that same listener. The delay speaker's electronic delay is set so its sound arrives your specified Haas offset (typically 5-20 ms) after the main PA's sound reaches that same spot — the calculator solves for exactly this, clamping to zero if the geometry would otherwise call for a negative delay.
The result converts to samples at 44.1, 48, and 96 kHz for direct entry into common digital delay processors. It also reports SPL drop-off from the main PA using the inverse-square law referenced to 1 metre, and calculates sound wavelengths at 100 Hz, 1 kHz, and 4 kHz, useful for anticipating comb-filtering and phase interference where the main and delay coverage zones overlap. This is a starting point for tuning, not a replacement for on-site measurement with a dual-channel analyzer, since real venues have reflections and temperature gradients this simple model doesn't capture.
Inputs
Results
Required delay (ms)
82.8
Delay (samples @ 48kHz)
3,974
How to Use This Calculator
- Enter the distance from the main PA speakers to the listener position near the delay speaker (m).
- Input the distance from the delay speaker to its nearest listeners (m).
- Enter the distance from main PA to the delay speaker location (m).
- Set the ambient air temperature (°C) so speed-of-sound is calculated accurately.
- Review the Delay Time (ms) to program into your audio processor for time-aligned sound.
How the result changes with Main PA to listener (m)
| Main PA to listener (m) | Required delay (ms) | Delay (samples @ 48kHz) |
|---|---|---|
| 15 | 39.12 | 1,878 |
| 23 | 62.41 | 2,996 |
| 45 | 126.48 | 6,071 |
| 75 | 213.83 | 10,264 |
What each input means
- Main PA to listener (m)
- Distance from the main PA speakers to the listener position near the delay speaker.
- Delay speaker to listener (m)
- Distance from the delay speaker to its nearest listeners.
- Main PA to delay speaker (m)
- Distance from main PA to the delay speaker location.
- Air temperature (°C)
- Ambient temperature — sound travels faster in warmer air.
- Haas offset (ms)
- Extra delay so the ear perceives the main PA as the source (5-20 ms typical).
What each result means
- Required delay (ms)
- Electronic delay to apply to the delay speaker's signal processor.
- Delay (samples @ 44.1kHz)
- Delay in audio samples at 44.1 kHz sample rate.
- Delay (samples @ 48kHz)
- Delay in audio samples at 48 kHz sample rate.
- Delay (samples @ 96kHz)
- Delay in audio samples at 96 kHz sample rate.
- Speed of sound (m/s)
- Speed of sound at the given temperature.
- Main PA travel time (ms)
- Time for sound from the main PA to reach the listener.
- Delay spkr travel time (ms)
- Time for sound from the delay speaker to reach its listener.
- Main PA SPL drop (dB)
- SPL reduction of the main PA at the listener distance (inverse square law).
- Wavelength at 100 Hz (m)
- Sound wavelength at 100 Hz for phasing reference.
- Wavelength at 1 kHz (m)
- Sound wavelength at 1 kHz.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersMain PA to listener (m) = 30, Delay speaker to listener (m) = 5, Main PA to delay speaker (m) = 25, Air temperature (°C) = 20 = 5 input(s) provided
- Calculate Required delay82.8 = 82.8
- Calculate DelayDelay3974 = 3974
- Calculate DelayDelay3651 = 3651
- Calculate DelayDelay7949 = 7949
Engine last updated . Checked against 3 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why do I want the delay speaker's sound to arrive AFTER the main PA instead of at the same time?
This relies on the Haas (precedence) effect: listeners localize a sound source to whichever arrival reaches their ears first, even if a later, louder sound arrives from a closer speaker. By deliberately delaying the delay speaker's electronic signal so its acoustic output reaches the listener a few milliseconds after the main PA's direct sound, the calculator keeps the audience perceiving the main PA as the source, avoiding the disorienting effect of sound seeming to come from the nearer delay speaker.
How much does air temperature actually change the required delay time?
Speed of sound is calculated as 331.3 plus 0.606 times temperature in °C, so a 20°C swing changes speed of sound by about 12 m/s — small in percentage terms, but over the long throw distances typical of outdoor delay setups that shift in travel time can move the calculated delay by several milliseconds, which matters when you're trying to land within a tight Haas offset window like 5-20 ms.
Why does the calculator give delay in samples at three different sample rates?
The required delay is first calculated in milliseconds from the geometry and Haas offset, then converted to samples by multiplying by 44.1, 48, or 96 (samples per millisecond at each common sample rate). This lets you enter the correct integer sample delay directly into a digital delay processor or DSP unit, whichever sample rate your system is running.
What are the wavelength figures at 100 Hz, 1 kHz, and 4 kHz actually used for?
They're the speed of sound (at your entered temperature) divided by each frequency, giving the physical wavelength in meters. These are useful for anticipating comb-filtering and phase interference: if the main PA and delay speaker coverage zones overlap by a distance close to a half-wavelength at a given frequency, you can expect cancellation or reinforcement at that frequency in the overlap zone.
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