Sound processing apparatus and sound processing system

A method of performing gain adjustment on sounds output from speakers, the method comprising:

• selecting four speakers;
• determining a position of a virtual speaker based on positions of the four speakers;
• calculating a gain of the virtual speaker by performing three-dimensional Vector Base Amplitude Panning (VBAP) based on a positional relationship among the virtual speaker, two speakers of the four speakers, and a sound image localization position;
• and
• performing gain adjustment on sounds to be output from at least the two speakers based on the gain of the virtual speaker, wherein the four speakers are configured to output sounds to a listener.

A non-transitory computer readable medium having stored thereon instructions that, when executed by a computer, perform a method, the method comprising:

• receiving a selection of four speakers;
• determining a position of a virtual speaker based on positions of the four speakers;
• calculating a gain of the virtual speaker by performing three-dimensional Vector Base Amplitude Panning (VBAP) based on a positional relationship among the virtual speaker, two speakers of the four speakers, and a sound image localization position;
• and
• performing gain adjustment on sounds to be output from at least the two speakers based on the gain of the virtual speaker, wherein the four speakers are configured to output sounds to a listener.