A method and apparatus for controlling the parking of a transducer head in a disk drive. A beverage dispensing apparatus includes an adjustable bypass manifold having an adjustable flow restriction that is configurable to enable the use of the beverage dispensing apparatus with different chilled soda recirculation systems. In the preferred embodiment, the method includes measuring the strength of the acoustic field applied to the cell or tissue at the applied frequency or other frequencies, and using the acoustic measurement to modify continued or subsequent application of acoustic energy to the cell or tissue. The communication system allows Internet access, movies, and other entertainment and business functions to be performed.