The Collaborative International Dictionary of English v.0.48:

microphonics \mi`cro*phon"ics\ (m[imac]`kr[-o]*f[o^]n"[i^]ks),
   n. [See Microphone.]
   The science which treats of the means of increasing the
   intensity of low or weak sounds, or of the microphone.
   [1913 Webster]