Phase-based localization tops out at 743 Hz at 90 degrees

Evidence

Thus for sounds at 90° the maximum frequency that can have its direction determined by phase is 743 Hz. However, the ambiguous frequency limit would be higher at smaller angles. — David Howard, Jamie Angus, coustics and Psychoacoustics, 719

Categorization

• CANDY: Specific number easy to share: the ear only uses phase to locate sounds below 743 Hz at the extreme angle.
• SEED: Could anchor a piece on why low-frequency directional hearing fails and how engineering compensates.
• XREF: connects to: Phase-based localization sensing has a hard frequency ceiling near 1.6 kHz — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1430