A method for inducing brain waves by sound has the following steps: receiving a first channel input signal and a second channel input signal; adjusting a volume gain of the first channel input signal to form a first channel output signal, wherein a format of the volume gain of the first channel output signal is a first wave format; adjusting a volume gain of the second channel input signal to form a second channel output signal, wherein a format of the volume gain of the second channel output signal is a second wave format, wherein there is a phase difference between the first wave format and the second wave format, wherein the formats of the first wave format and the second wave format are the same; outputting the first channel output signal to a first speaker; and outputting the second channel output signal to a second speaker.
Method for inducing brainwaves by sound and sound adjusting device