The 3-D plot and spectrogram are typical of the 'moving hand'
situation. When the hand is far, the AEPTF resembles the baseline measurements.
As the hand moves close to the ear, a resonance moves from 2 to 4kHz.
This resonance moves at a rate of 2kHz/second. As the hand makes its closest
approach to the ear, a new resonance begins to appear at 1.5kHz.
The greatest rate of change occurs near 4kHz as the hand moves close to the ear. Here, the AEPTF changes at a rate of 7dB over a 250msec interval.