First Floor Reflection Delay Calculator

Method, formula and assumptions

The image-source floor path is sqrt(horizontalDistance^2 + (sourceHeight + listenerHeight)^2). The direct path uses the height difference. First equal-level same-polarity cancellation = sound speed / (2 x extra path).

Input definitions and supported units

• Horizontal source-to-listener distance (m): Measured or assumed numerical value, from 0.01 to 100; must be positive.
• Source height above floor (m): Measured or assumed numerical value, from 0.01 to 20; must be positive.
• Listener height above floor (m): Measured or assumed numerical value, from 0.01 to 20; must be positive.
• Assumed sound speed (m/s): Measured or assumed numerical value, from 100 to 500; must be positive.

Worked example with answer

At 3 m horizontal separation with both heights 1 m, direct path is 3 m and floor path is 3.6056 m. At 340 m/s the extra delay is 1.781 ms and the first ideal cancellation is 280.7359 Hz.

How to use the results

Changing source or ear height shifts the path difference. This is a single-reflection geometry exercise; it helps select positions to measure, not promise a flat response.

Results retain full precision internally and display up to four decimal places. Very small nonzero results use scientific notation rather than appearing as zero. Check the labels before comparing values across units.

Limitations and references

Assumes a flat floor and specular reflection. Carpet, absorption, phase changes, source directivity and other room surfaces change cancellation depth and frequency.

The method is a self-contained arithmetic, geometric or explicitly stated mathematical model. There are no imported tariffs, empirical presets or equipment specifications; measured values and allowances must come from your own process.

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