• Dolby Broadcast Loudness Meter LM100

    • The Dolby Broadcast Loudness Meter LM100 is a tool that provides objective, accurate measurements of the subjective loudness of dialogue within broadcast programming.

    • Dolby Broadcast Loudness Meter LM100

      • Measure Broadcast Loudness Accurately

        Differences in audio levels between programs, or between programs and commercials, are a major annoyance to TV viewers. However, these differences have proven difficult for broadcasters to measure with conventional methods and equipment. The Dolby® Broadcast Loudness Meter LM100 solves that problem through Dialogue Intelligence™, a revolutionary technology developed specifically to measure the perceived loudness of dialogue.

        Research shows that most viewers adjust TV volume to normalize dialogue levels. By analyzing the input signal and measuring program loudness only during the presence of speech, Dialogue Intelligence objectively measures what viewers subjectively experience.

        Wide Range of Use Cases

        Applications for the Dolby LM100 range from postproduction and quality control to final transmission, program turnaround, and cable headend facilities.

        Measures Using International Standards

        The Dolby LM100 loudness meter can use ITU-R BS.1770-1 and BS.1770-2 as the core measurement algorithm. Users can also select Leq(A) or EBU R128.* The LM100 can also determine the unweighted peak and a range of other information about the signal, including the Loudness Range measurement specified by the EBU.

        Easy-to-Read Measurements

        The Dolby LM100 presents its measurements in an easy-to-understand numerical format. This eliminates the variations in results that multiple operators often find when using VU or PPM meters, neither of which was designed to measure subjective loudness. The unit can simultaneously display the incoming dialogue normalization (dialnorm) value of a Dolby Digital program (or any program within a Dolby E bitstream) for direct comparison to the actual measured value.

        Complete User Notifications

        A set of user-definable alarms and monitoring functions can inform an operator of input loss, signal clipping, overmodulation (LM100-NTSC version), high or low signal levels, silence, and incorrectly set dialnorm values.

        Remote Control Capability

        Front- and rear-panel serial interfaces provide capabilities for software updates and the Dolby LM100 software remote application. The remote application will assist users with advanced loudness measurement, logging features, and enhanced error reporting.

        Two Configurations

        The LM100-LTC includes a timecode input, which allows alarm and other signal conditions to be logged to either the internal time-of-day clock or external timecode. The LM100-NTSC includes an RF input specifically for NTSC CATV and "off-air" television measurement applications. Because the RF tuner replaces the linear timecode input in this version, logging is referenced to the internal clock.

        * For units manufactured prior to September 2011, Dolby offers a software upgrade option that adds the latest features, including the ITU-R BS.1770-2 algorithm.

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      • Dolby LM100 Specifications

        Core Measurement Algorithm (User Selectable)

        • EBU R128
        • ITU-R BS.1770-2
        • ITU-R BS.1770-1
        • Leq(A)

        Dialogue Intelligence Algorithm

        • Proprietary; patent pending

        Audio Sampling Rates

        • 32, 44.1, and 48 kHz

        Measurement/Analysis System Log

        • 480 events stored in internal nonvolatile RAM
        • Unlimited event storage and retrieval with use of LM100 software remote application on a PC

        Power Requirements

        • 90–264 VAC, 50–60 Hz, autosensing, 15 W maximum; designed to operate from a centrally switched power source

        Dimensions and Weight

        • 1-U rackmount: 44 × 483 × 375 mm (1.75 × 19 × 14.75 inches)
        • Net: 2.5 kg (5.5 lb)

        Environmental Conditions

        • Operating: 0°C–50°C (32°F–122°F), natural convection cooling, 0%–98% relative humidity (noncondensing)
        • Nonoperating: –20°C to +70°C (–4°F to 158°F)

        Dolby LM100 Front Panel Specifications

        Display and Controls

        • Intuitive, easy-to-read user interface; input source selection determines display parameters


        • Enables local control of setup functions and status display

        Alarm LEDs

        • Audio alarm, fault, and error

        Headphone Output

        • 6.35 mm (1/4-in.) standard stereo headphone jack, level-adjustable for confidence monitoring

        RS-232 Serial Remote Control Input Port

        • 8-pin female mini-DIN connector for the LM100 software remote application and software upgrades

        Dolby LM100 Rear Panel Specifications

        Digital Audio Input

        • BNC female connector with loop-through, unbalanced, 75Ω, signal levels per AES-3ID-1995 (SMPTE 276M), external 75Ω termination required Formats supported: PCM data up to 24 bits; Dolby E data supported in 16-, 20-, and 24-bit modes at 48 kHz; Dolby Digital (AC-3) data at 32, 44.1, and 48 kHz sample rates

        Analog Audio Inputs

        • Two Neutrik® combination XLR/¼-inch TRS connectors, electronically balanced; maximum input level: ~ +22 dBu
        • Input impedance: 10 kΩ; user-definable nominal operating levels

        Analog Audio Outputs

        • Two RCA-type connectors, unbalanced, stereo; maximum output level: 2 Vrms into a 10 kΩ load per IEC 61938

        Timecode Input (LM100-LTC version)

        • BNC female, unbalanced, per SMPTE 12M-1999

        RF Input (LM100-NTSC version)*

        • F-type female connector with internal 75Ω termination; tuner frequency range: 55.25–801.25 MHz; supports BTSC encoded stereo signals
        • Selectable CATV or "off-air" modes; CATV mode supports the Cable Television Channel Identification Plan per EIA 542 (user-selectable: Standard, HRC, or IRC); video output: composite, BNC female

        RS-485 Serial Remote Control

        • Input port 9-pin female D-connector for remote control and software upgrades

        Alarm Port

        • 9-pin female D-connector, 0–5 V TTL level; user-definable alarms: input clip detection, modulation overload, loudness above threshold, loudness below threshold (silence), dialnorm threshold, and AES input loss

        General Purpose Input/Output Port

        • 9-pin female D-connector, 0–5 V TTL level
        • Functions include: measurement pause, measurement reset, input source select, channel up/down (LM100-NTSC only), measurement state

        *The NTSC input replaces the LTC input on this version.

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