Sound waves vibrating the eardrum excite the ossicles in the middle ear ultimately driving waves in the cochlea. Cochlear vibrations are processed by inner hair cells and outer hair cells (OHCs). Our focus is on the OHCs that nonlinearly amplify the sound converting a time-varying motion of its apically adorned hair bundle (HB) to an alternating current. The OHC HB consists of roughly three rows of stereocilia arranged according to their heights. Understanding how the bundle stiffness, sensitivity, and transduction current depend on the physiology and anatomy of the stereocilia is crucial and an open question. Therefore, we are developing a three-row model of an isolated HB to quantify each row’s contribution to the passive and active mechanics of the HB. The derived equations of motion include the nonlinear kinematics, viscoelastic HB mechanics, and the nonlinear response of the mechano-electric transducer channels coupled to an adaptation mechanism. We also linearize the model to conduct stability analysis and determine the dependence of the responses on the rate constants. Our preliminary results show a higher current influx through the middle row than the shortest row and closely predicts the biophysical parameters like the sensitivity and stiffness of the bundle.