Audio distortion correction for a parametric reproduction system

A method of distortion reduction in a non-linear audio system, comprising the steps of:

• defining a non-linear system transfer function which relates a system electronic input signal with a system acoustic output and is valid over a range of input amplitude levels corresponding with at least a portion of a range of acoustic output sound pressure levels in which the system acoustic output is in a transition between non-saturated and saturated conditions in a medium in which the system acoustic output of the non-linear audio system is broadcast;
• creating a preprocessing transfer function which is the solved inverse of the non-linear system transfer function;
• and
• applying the preprocessing transfer function to the system electronic input signal to form a pre-processed electronic input signal, wherein the pre-processed electronic input signal is configured to provide a modified system acoustic output having a reduced level of harmonic distortion relative to the system acoustic output;
• wherein the preprocessing transfer function is of the form:
• y
• ⁡
• (
• t
• )
• =
• [
• E
• ⁡
• (
• t
• )
• +
• u
• 2
• 3
• ⁢
• E
• ⁡
• (
• t
• )
• 2
• ]
• 1
• /
• 2
• wherein y(t) is the preprocessed electronic audio signal, E(t) is the input electronic audio signal, and u is an ultrasound pressure index value.