Non-transitory computer-readable medium having computer-readable instructions and system

A user terminal configured to mix a backing sound and a guitar sound, comprising:

• an input device configured to receive a first input instruction selected from a plurality of available input instructions, where the plurality of available input instructions include a first instruction to transmit a signal of the backing sound;
• a wireless communication device, connected to the input device;
• a sound source configured to provide the signal of the backing sound to the wireless communication device in response to the first input instruction being the first instruction to transmit the signal of the backing sound;
• and
• a central control unit, configured to control the wireless communication device to convert the signal of the backing sound to a first wireless signal and transmit the first wireless signal to a sound output device for mixing the signal of the backing sound and a signal of the guitar sound provided from the sound output device.