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Dorrough 240-A2 & 340-A2 Surround Sound Meters

Discussion in 'Metering VU' started by audiokid, Oct 25, 2011.

  1. audiokid

    audiokid Staff


    The Model 240-A and 340-A are single channel straight line loudness meters ideal for applications where serveral meters are required, such as Surround Sound. The Model 240-A is designed for horizontal mounting, while the model 340-A is designed for vertical mounting.

    These meters are ideal for HDTV 5.1 and 7.1 Surround Sound applications. Two custom mounting solutions tailored to this application are offered as options. The first choice is a metal rack adapter 5RU high, which accommodates 5 vertical (340-A) meters and a single horizontal (240-A) meter used for the .1 (LFE) channel at the bottom (shown below).


    For Models 40-A, 10-A, 20-A, 12-A, 240-A, 280-A, 380-A, 400-A.

    Input Parameters
    Input Z : 20k Ohm balanced, 10k Ohm single-ended, +- 2%
    TD="width: 100%"CM : 80 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

    BSignal Path ParametersB

    *Signal Path Bandwidth : 10 Hz - 25 kHz, +- .25 dB
    *Signal Path Distortion : Less than 1% THD at 1 kHz, +24 dB input
    *Sum Error : Less than 0.1 dB at 1 kHz
    *Difference Error : Less than 0.1 dB at 1 kHz
    Display Parameters (All parameters apply to AVERAGE, PEAK, and PEAK HOLD display elements.)

    *Display Resolution : 40 LEDs, 1 dBLED except model 60D, +- 0.25 dB.
    *Step Size Error : +- 0.25 dB
    *Absolute Error :

    - Full Scale -39 dBu : +- 0.25 dB model A,B,C
    - Full Scale -59 dBu : +- 0.25 dB model D

    *Drift : +- 0.25 dB
    *Average Time Constant : 600 mS, +- 6%
    *Peak Acquistion Period : 10 uS, to full-scale, sine input 25kHz
    *Peak Attack Period : Virtually Instantaneous
    *Peak Decay Period : 180 mS, from full-scale to all LEDs off (models A, B, C)
    *Display Update Rate : Approximately 10 mS
    *Display Duty Cycle : Display Time, AVERAGE, PEAK HOLD - 75%

    Display Time, PEAK - 100%

    Miscellaneous Parameters

    *Power Supply Input Range : 117237 VAC RMS, -20% to +10%, 50-60 Hz
    *Calibration Controls : None needed
    *User Controls :

    LeftRight input sensitivity
    Option DIP Switch
    A) Peak Auto ON
    B) Difference Mode ONOFF
    C) Over Level Alarm ENABLE
    D) Under Level Alarm ENABLE
    E) Auto ARMP

    *User Port :

    DB-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)

    Attached Files:

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