The Dorrough 21C Vertical Analog Loudness Meter +20 dB is a single-channel version of Dorrough's standard 40 series loudness meter with a straight-line scale display scale allowing 20 dB of headroom in 1 dB steps. The headroom scale is identical to the AES/EBU Digital Standard.
This meter provides access phase correlation, peak hold, sum/diff, and reference mode allowing 0 reference setting to 0.1 dB accuracy, directly or with the optional remote control. It has Phoenix (euroblock) connectors. Rack mounting is required.
Peak and Average Level Metering
The 21C, like all Dorrough loudness meters, simultaneously displays peak and average, in this model down to +20 dB. The relative difference, in dB, between Peak and Average ballistics is derived from the integration time of the persistence scale.
Right and Left Inputs for Stereo Mixing
With one instrument, the operator can easily see the stereo mix and avoid classic in-phase/out-of-phase problems as well as center channel buildup that can cause a mix to seem louder. This is especially important in preparing stereo program material for broadcast, while still being able to maintain monaural compatibility.