It refers to the ratio of the normal sound signal played back by the speaker to the noise signal (power) when there is no signal. Expressed in dB. For example, the signal-to-noise ratio of a speaker is 80dB, that is, the output signal power is 80dB greater than the noise power. The higher the signal-to-noise ratio, the lower the noise.
The minimum requirements of the International Electrotechnical Commission for the signal-to-noise ratio are that the preamplifier is greater than or equal to 63dB, the post-amplifier is greater than or equal to 86dB, and the combined amplifier is greater than or equal to 63dB. The best value of the signal-to-noise ratio of the combined amplifier should be greater than 90dB, the signal-to-noise ratio of the CD player can reach more than 90dB, and the high-end one can reach more than 110dB. When the signal-to-noise ratio is low, the noise is serious during small signal input, and the sound of the entire range is obviously muddy. Therefore, it is not recommended to buy speakers with a signal-to-noise ratio of less than 80dB, and a subwoofer with a subwoofer of 70dB is not recommended for the same reason.