A sound signal processing method includes receiving a sound signal, generating an early reflection sound control signal that reproduces an early reflection sound and a reverberant sound control signal that reproduces a reverberant sound from the sound signal, controlling a volume of the sound signal and distributing the sound signal to generate a direct sound control signal, and mixing the direct sound control signal, the early reflection sound control signal that reproduces a direct sound, and the reverberant sound control signal to generate an output signal.