AC: A signal with the set frequency weighting is output. It is delayed about 4.6 ms to the actual sound by the frequency weighting filter.

AC/DC: AC-Z: Regardless of the set frequency weighting characteristic, the signal processed by Z-weighting filtering is output.
DC: A voltage corresponding to the magnitude of the sound pressure level (dB value) is output.
Through: This is a signal that is not processed with frequency weighting filter. Since it is not filtered, there is no delay.