Audio processing apparatus and audio processing method

An audio processing method for an audio processing apparatus including a plurality of channel operation controllers associated with a plurality of channels, each of the plurality of channel operation controllers configured to be operable by a user to control a parameter for one of the plurality of channels, the method comprising:

• determining a first channel, among the plurality of channels, to be assigned to a first channel operation controller, among the plurality of channel operation controllers;
• and
• receiving, using a switching operation controller, an operation from the user to switch between a fixed mode where the first channel assigned to the first channel operation controller is fixedly set in advance and a custom mode where the first channel assigned to the first channel operation controller is arbitrarily settable,
• wherein the custom mode includes:
• a first state where the switching operation controller is configured to receive a first operation from the user to switch from the custom mode to the fixed mode;
• and
• a second state where the switching operation controller is configured to receive a second operation, different from the first operation, from the user to switch from the custom mode to the fixed mode.