The outer hair cell (OHC) membrane harbors a voltage-dependent protein, prestin 
(SLC26a5), in high density, whose charge movement is evidenced as a nonlinear 
capacitance (NLC). NLC is bell-shaped, with its peak occurring at a voltage, Vh, 
where sensor charge is equally distributed across the plasma membrane. Thus, Vh 
provides information on the conformational state of prestin. Vh is sensitive to 
membrane tension, shifting to positive voltage as tension increases and is the 
basis for considering prestin piezoelectric (PZE). NLC can be deconstructed into 
real and imaginary components that report on charge movements in phase or 90 
degrees out of phase with AC voltage. Here we show in membrane macro-patches of 
the OHC that there is a partial trade-off in the magnitude of real and imaginary 
components as interrogation frequency increases, as predicted by a recent PZE 
model (Rabbitt in Proc Natl Acad Sci USA 17:21880-21888, 2020). However, we find 
similar behavior in a simple 2-state voltage-dependent kinetic model of prestin 
that lacks piezoelectric coupling. At a particular frequency, Fis, the complex 
component magnitudes intersect. Using this metric, Fis, which depends on the 
frequency response of each complex component, we find that initial Vh influences 
Fis; thus, by categorizing patches into groups of different Vh, (above and 
below - 30 mV) we find that Fis is lower for the negative Vh group. We also find 
that the effect of membrane tension on complex NLC is dependent, but 
differentially so, on initial Vh. Whereas the negative group exhibits shifts to 
higher frequencies for increasing tension, the opposite occurs for the positive 
group. Despite complex component trade-offs, the low-pass roll-off in absolute 
magnitude of NLC, which varies little with our perturbations and is indicative 
of diminishing total charge movement, poses a challenge for a role of 
voltage-driven prestin in cochlear amplification at very high frequencies.