FIGURE 6.

Magnitude and phase of the ratio H_Tip(f) of Tip to RL displacement for two hair bundles with heights of 15 μm (left) and 26 μm (right). Circles show individual measurements; at some frequencies, multiple independent measurements were made at each frequency by analyzing motion at different planes. The magnitude of H_Tip(f) was slightly >1, and nearly constant with frequency. The phase fell from near zero at low frequencies to near −90° for the shorter hair bundle, and near −180° for the taller hair bundle at high frequencies. Solid lines show the least squares fit of an ideal time delay to the phase; the delays were 16 μs and 52 μs for the shorter and taller bundles, respectively. For the taller bundle, the best-fit time delay overestimated the phase lag at low frequencies and underestimated the lag at high frequencies.