Optimisation of controlled acoustic shadows

This paper considers the acoustic interference across high frequency source distributions and how to generate an acoustic shadow from these sources using a controlled array of discrete cancelling sources. The optimum shadow depth as a function of the canceller density is considered including optimum system parameters. The behaviour of the secondary sources and how they organise themselves in phase and amplitude to cancel the primary field is investigated, together, with details of the antifield and resulting residual field (shadow). Finally, the special case of excessive canceller effort to produce the near perfect shadows is also considered