An information processing system, comprising: a device configured for performing timbre control; an information processing device, comprising: a control part, receiving an input of information indicating one or more times in a playback time of a musical piece, and generating a file comprising information pertaining to a timbre control to be performed from each of the one or more times in the playback time of the musical piece; a display part, displaying a memory number pertaining to the timbre control to be performed from the one or more times in the playback time of the musical piece and a marker indicating each of the one or more times in the playback time of the musical piece on a single seek bar, wherein the memory number is information specifying a set of timbre parameters for processing a timbre of a playing sound of a musical instrument played by a user to a predetermined timbre; and characterised by comprising a transmission part, in response to a playback instruction, transmitting an audio signal of the musical piece, and transmitting, before a designated time set in a marker among the one or more markers arrives, information comprising the set of timbre parameters on the memory number corresponding to the designated time to the device that performs the timbre control in accordance with the transmission of the audio signal, wherein when the designated time set in the marker among the one or more markers arrives, the device performs the timbre control on the playing sound of the musical instrument played by the user using the set of timbre parameters of the memory number corresponding to the designated time and outputs a synthetic sound of a playback sound of the musical piece and the playing sound of the musical instrument with the timbre control being performed. a device configured for performing timbre control; an information processing device, comprising: a control part, receiving an input of information indicating one or more times in a playback time of a musical piece, and generating a file comprising information pertaining to a timbre control to be performed from each of the one or more times in the playback time of the musical piece; a display part, displaying a memory number pertaining to the timbre control to be performed from the one or more times in the playback time of the musical piece and a marker indicating each of the one or more times in the playback time of the musical piece on a single seek bar, wherein the memory number is information specifying a set of timbre parameters for processing a timbre of a playing sound of a musical instrument played by a user to a predetermined timbre; and characterised by comprising a transmission part, in response to a playback instruction, transmitting an audio signal of the musical piece, and transmitting, before a designated time set in a marker among the one or more markers arrives, information comprising the set of timbre parameters on the memory number corresponding to the designated time to the device that performs the timbre control in accordance with the transmission of the audio signal, wherein when the designated time set in the marker among the one or more markers arrives, the device performs the timbre control on the playing sound of the musical instrument played by the user using the set of timbre parameters of the memory number corresponding to the designated time and outputs a synthetic sound of a playback sound of the musical piece and the playing sound of the musical instrument with the timbre control being performed. a control part, receiving an input of information indicating one or more times in a playback time of a musical piece, and generating a file comprising information pertaining to a timbre control to be performed from each of the one or more times in the playback time of the musical piece; a display part, displaying a memory number pertaining to the timbre control to be performed from the one or more times in the playback time of the musical piece and a marker indicating each of the one or more times in the playback time of the musical piece on a single seek bar, wherein the memory number is information specifying a set of timbre parameters for processing a timbre of a playing sound of a musical instrument played by a user to a predetermined timbre; and characterised by comprising a transmission part, in response to a playback instruction, transmitting an audio signal of the musical piece, and transmitting, before a designated time set in a marker among the one or more markers arrives, information comprising the set of timbre parameters on the memory number corresponding to the designated time to the device that performs the timbre control in accordance with the transmission of the audio signal, wherein when the designated time set in the marker among the one or more markers arrives, the device performs the timbre control on the playing sound of the musical instrument played by the user using the set of timbre parameters of the memory number corresponding to the designated time and outputs a synthetic sound of a playback sound of the musical piece and the playing sound of the musical instrument with the timbre control being performed.