a speaker apparatus has a container holding a volume of ferrofluid , a permanent magnet suspended in the ferrofluid , and a magnetic excitation apparatus proximate the container . operation of the excitation apparatus causes movement of the permanent magnet , translated through the ferrofluid to walls of the container , which walls act as resonators creating sound waves in surrounding medium . audio production is accomplished placing a ferrofluid and a permanent magnet in a container , placing an excitation apparatus in proximity of the permanent magnet , and driving the excitation apparatus to cause movement of the permanent magnet translated through the ferrofluid to walls of the container , which walls act as resonators creating sound waves in surrounding medium .