a method and apparatus for detecting mechanical interaction in a disk drive system which includes one or more rotatable disks , one or more radially movable heads cooperating with the disks for transfer of data there between , and a carriage for supporting the heads , has a waveguide , coupled to the carriage , for conducting acoustic stress waves corresponding to the mechanical interaction . the acoustic stress waves conducted from the carriage are then preamplified and selectively filtered before being fed to a signal processor and waveform analyzer . in such a manner , specific frequencies or ranges of frequencies of interest , each of which correspond to a particular mechanical interaction are analyzed by the waveform analyzer .