Phase & timing
Path Difference & Phase Calculator
Convert an acoustic path-length difference into delay, cycle offset and phase shift at a selected frequency.
Convert path difference to phase
Enter the path-length difference, frequency and air temperature.
Why path difference creates phase shift
If two versions of the same signal travel different acoustic distances, they arrive at different times. At any given frequency that delay corresponds to a fraction of a cycle, which can create reinforcement, cancellation or comb filtering when the signals combine.
Phase is frequency dependent
A fixed path difference does not create one universal phase angle. The angle changes with frequency because each frequency has a different period and wavelength. That is why spaced microphones and multiple acoustic paths produce a repeating comb-filter pattern rather than one constant level change.
Use phase with context
The wrapped angle is useful for understanding one frequency, but the associated time delay is usually the more general description of the offset. Polarity inversion is not the same thing as a broadband time delay, even though both can produce a 180° relationship at particular frequencies.