Speaker Delay Alignment Calculator

How it is calculated

First the speed of sound is found from air temperature: c = 331.3 × √(1 + T / 273.15), with T in °C and c in m/s. Then the path difference between the two speakers is taken as an absolute value: Δd = |d2 − d1| in metres, and the delay is t = Δd / c × 1000 milliseconds. The result does not say which speaker is which: the delay always belongs on the speaker that is closer to the listener, and the farther one gets none. If the temperature is left blank the engine assumes 20 °C; a temperature below −100 or above 150 °C gives no result. Distances must be zero or more; equal distances give 0 ms.

Common mistakes

• Measuring distances between the two speakers instead of from each speaker to the listening position. Only the two listener distances matter.
• Putting the delay on the far speaker. The delay is added to the speaker nearer the listener so it waits for the far one.
• Entering the temperature in °F. The field expects °C, and a value like 68 would give a speed of sound far too high.
• Using the 20 °C default for an outdoor show on a cold or hot day. For 15 m of path difference, 0 °C gives 45.28 ms and 30 °C gives 42.98 ms, so the 20 °C default is off by a couple of milliseconds.
• Entering feet in a metre field. The distances are metres, so 50 ft must be typed as about 15.2.