Dorrough 240-C Surround Sound Meter +20dB

BH #DO240C • MFR #240-C
Dorrough 240-C Surround Sound Meter +20dB
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Dorrough 240-C Overview

  • 1Description
  • 2Actual Energy Display
  • 3Peak and Average Level Metering
  • 4Right and Left In puts for Stereo Mixing
  • 5Made for Surround Sound Applications

The Dorrough 240-C Surround Sound Meter +20dB is a single-channel straight-line display loudness meter with 20dB headroom. It is used for applications where serveral meters are required and ideal for HDTV 5.1 and 7.1 Surround Sound applications. The Model 240-A is designed for horizontal mounting and is outfitted for XLR connections.

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.

Peak and Average Level Metering

The 240A, like all Dorrough loudness meters, simultaneously displays peak and average. The relative difference, in dB, between these two ballistics is derived from the integration time of the persistence scale.

Right and Left In puts 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.

Made for Surround Sound Applications

This single channel straight line loudness meter is ideal for applications where serveral meters are required, such as Surround Sound. They are particularly useful for HDTV 5.1 and 7.1.

Dorrough 240-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)

Dimensions5.0 x 7.5 x 1.5" (in.) (2.0 x 3.0 x .6cm)
WeightNot Specified by Manufacturer
Packaging Info
Package Weight1 lb
Box Dimensions (LxWxH)1 x 1 x 1"
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