Speaker Delay Alignment Calculator
A delay or fill speaker closer to the audience reaches listeners before the main system, smearing the image. Time-aligning the two means delaying the nearer speaker by the extra travel time of the main speaker's sound. This calculator finds that delay from the two distances and the speed of sound, which depends on temperature and is therefore a user input. Add a small Haas precedence offset if you want the audience to localise to the main system.
Delay alignment formula
distance difference = main distance - delay distance
alignment delay (ms) = distance difference / speed of sound * 1000
total delay = alignment delay + Haas offset
samples = total delay / 1000 * 48000
Sound covers the distance difference in (difference / speed) seconds. Delaying the nearer speaker by that time aligns arrivals. The 48 kHz sample count helps when setting delay on digital processors.
Alignment facts
- At 343 m/s, sound travels about 0.343 metres per millisecond.
- The speed of sound rises roughly 0.6 m/s for each degree Celsius of warming.
- A Haas offset of 5 to 15 ms keeps localisation on the main system.
- If the delay speaker is farther than the main, no positive delay is needed.
- Sample counts depend on the processor sample rate; this uses 48 kHz.
Speaker delay: frequently asked questions
Why do you add delay to loudspeakers?
When a near (fill or delay) speaker is closer to a listener than the main speaker, its sound arrives first. Adding electronic delay equal to the extra travel time of the main speaker's sound makes both arrive together, preserving the sense that sound comes from the stage.
How is the delay time calculated?
Delay equals the distance difference divided by the speed of sound, converted to milliseconds. If the main speaker is 30 metres away and the fill speaker is 10 metres, the 20-metre difference at 343 m/s gives 20 / 343 times 1,000 = 58.3 milliseconds.
What speed of sound should I use?
The speed of sound depends on air temperature, roughly 343 metres per second at 20 degrees Celsius. It is a user input here because it changes with temperature; about 0.6 metres per second per degree Celsius. Outdoor shows may use a different value than a heated hall.
Should I add the Haas effect offset?
Many engineers add a small extra delay, often 5 to 15 milliseconds, so the delayed speaker arrives slightly after the main. This Haas (precedence) offset makes the brain localise the sound to the main system. This calculator gives the exact physical alignment; add your chosen offset on top.
Does this work for subwoofer alignment?
The same distance-to-time principle applies, but subwoofer alignment also depends on phase and crossover, so use the physical delay as a starting point and verify with measurement. For full-range fills the distance delay is usually the dominant term.
Official sources
- National Institute of Standards and Technology: SI units and the second.
- Acoustical Society of America: sound reinforcement references.
Reviewed by the CalculatorHub team, edited by James Graham, 16 June 2026. See our methodology.