Dorrough 12-C Analog Loudness Meter +20dB

BH #DO12C • MFR #12-C
Dorrough 12-C Analog Loudness Meter +20dB
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  • This item is noncancelable and nonreturnable.
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Dorrough 12-C Overview

  • 1Description
  • 2Actual Energy Display
  • 3Dual Meters
  • 4Peak and Average Level Metering
  • 5Right and Left Inputs for Stereo Mixing

The Dorrough 12-C Analog Loudness Meter +20dB is dual version of Dorrough's 10-C single-channel loudness monitor. The meter scale allows for 20dB of headroom in 1dB 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 .1dB accuracy, directly or with the optional remote control. Rack mounting is required.

Actual Energy Display

Dorrough Loudness Meters display actual energy content of the program material, regardless of frequency, while still indicating the peak amplitude of the complex audio signal. This feature allows all program material to be adjusted for equal perceived loudness while protecting the peak of the waveform.

Dual Meters

With these easy to read monitors you can view two channels or projects simultaneously, side-by-side. They are made to install easily to custom console or with optional rack mounts. Dorrough rack adapters for the model 12-A are available with cutouts for either single or double meters. Both are 2RU high and 19" wide.

Peak and Average Level Metering

The 12-C, like all Dorrough loudness meters, simultaneously displays peak and average, in this model up to +20dB. The relative difference, in dB, between these two 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.

Dorrough 12-C Specs

Input Impedance20k Ohm balanced, 10k Ohm single-ended, +/- 2%
Common Mode Rejection Ratio80 dB at 60 Hz, 60 dB at 20 kHz (balanced mode)
Input Sensitivity-10 dB for full-scale display
Maximum Input Level+24 dB before clipping
Signal Path Bandwidth10 Hz - 25 kHz, +/- .25 dB
Signal Path DistortionLess than 1% THD at 1 kHz, +24 dB input
Sum ErrorLess than 0.1 dB at 1 kHz
Difference ErrorLess than 0.1 dB at 1 kHz
Display ResolutionLess than 0.1 dB at 1 kHz
Step Size Error+/- 0.25 dB
Absolute ErrorFull Scale -39 dBu: +/- 0.25 dB model A,B,C
Drift+/- 0.25 dB
Average Time Constant600 mS, +/- 6%
Peak Acquisition Period10 uS, to full-scale, sine input 25kHz
Peak Attack PeriodVirtually Instantaneous
Peak Decay Period180 mS, from full-scale to all LEDs off (models A, B, C)
Display Update RateApproximately 10 mS
Display Duty CycleDisplay Time, AVERAGE, PEAK HOLD - 75%

Display Time, PEAK - 100%

Power Supply Input Range117/237 VAC RMS, -20% to +10%, 50-60 Hz
Calibration ControlsNone Needed
User ControlsLeft/Right input sensitivity Option DIP Switch

A) Peak Auto [ON]

B) Difference Mode [ON/OFF]

C) Over Level Alarm [ENABLE]

D) Under Level Alarm [ENABLE]

E) Auto ARMP

User PortDB-9 Connector A) Alarm relay closure contacts 1 form C, 1A, 30V AC or DC

 B) Mode control switch (user supplied)

C) PEAK function switch (user supplied)

Dimensions8.6 x 3.0 x 2.0" (in.) (3.4 x 1.2 x 0.8cm)
WeightNot Specified by Manufacturer
Packaging Info
Package Weight1.65 lb
Box Dimensions (LxWxH)11.4 x 9.2 x 5.1"
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