ITD applies to which frequency range?

ITD applies to which frequency range?

• A. Mid Frequencies (3-6 kHz)
• B. High Frequencies (> 3 kHz)
• C. All frequencies
• D. Low Frequencies (< 3 kHz)

Answer: (D)

Interaural time differences are most informative for sounds with long waveform cycles, because the timing of the arrival at each ear can be tracked precisely. At low to moderate frequencies, the auditory system can phase-lock to the waveform, so neurons fire at specific phases of the cycle and encode tiny differences in arrival time between the two ears. This makes the timing difference a reliable cue for localizing sounds along the horizontal plane, especially up to a few kilohertz. As frequency climbs, cycle duration becomes so short that small timing differences can correspond to multiple possible phases, causing phase ambiguity and weakening ITD as a cue. In that range, the brain relies more on interaural level differences created by the head’s shadow. So interaural time differences apply best to low frequencies, typically below about 3 kHz.

Interaural time differences are most informative for sounds with long waveform cycles, because the timing of the arrival at each ear can be tracked precisely. At low to moderate frequencies, the auditory system can phase-lock to the waveform, so neurons fire at specific phases of the cycle and encode tiny differences in arrival time between the two ears. This makes the timing difference a reliable cue for localizing sounds along the horizontal plane, especially up to a few kilohertz. As frequency climbs, cycle duration becomes so short that small timing differences can correspond to multiple possible phases, causing phase ambiguity and weakening ITD as a cue. In that range, the brain relies more on interaural level differences created by the head’s shadow. So interaural time differences apply best to low frequencies, typically below about 3 kHz.