A hearing assistance system (200) includes multiple middle ear transducers (205) for sensing vibrations of an ossicle or other auditory element. The hearing assistance system is configured to accommodate an unknown or variable direction of the vibration. Two transducers are arranged to transduce nonidentical directional components of the vibration into electrical signals which are then combined. The combined electrical signal is approximately independent of the direction of the vibration, or has improved frequency response, or has an amplitude that is approximately independent of the direction of the vibration. The combined electrical signal may result from a square root of sum-of-squares, sum of individually filtered signals, differentiation, or other techniques. The hearing assistance system analogously accommodates three-dimensional variability of the direction of vibration using three middle ear transducers.