Loudness Report, Part 3: Got Loud If You Want It
By Dan Daley
To cap our series on broadcast loudness issues, here’s a look are some of the products on the market designed to help mixers and other audio mavens deal with them.
The Dolby LM100 Broadcast Loudness Meter (priced at $3,200) uses the company’s proprietary Dialogue Intelligence algorithm developed specifically to measure the perceived loudness of dialogue. The LM100 utilizes ITU-R BS.1770-1 as its core measurement algorithm; users can also select Leq(A). The LM100 can determine the unweighted peak and a range of other information about the signal. 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.
The Dolby DP600–C Program Optimizer ($17,500 for base model, $26,000 with transcoding capability) provides automatic file-based loudness analysis and correction for broadcaster audio. It analyzes and corrects the dialnorm metadata parameter in Dolby E and Dolby Digital bitstreams and provides intelligent and automatic speech-based loudness normalization for both PCM and MPEG-1 LII audio files. Additionally, the DP600–C offers faster-than-real-time file-based encoding, decoding, and transcoding of Dolby Digital, Dolby Digital Plus, and Dolby E bitstreams and MPEG-1 LII audio files, as well as single-step Dolby Digital-to-Dolby Digital Plus transcoding that preserves the metadata and minimizes tandem coding losses.
Linear Acoustic’s LAMBDA professional digital audio and metadata monitor ($6,750) provides operators with a built-in method for quickly verifying program loudness. With loudness monitoring using ITU BS.1770 measurement, LAMBDA reproduces up to 16 audio channels via AES or embedded HD-SDI input. It can monitor any channel, channel pair, or Lt-Rt or Lo-Ro downmix through the two-way, digitally amplified speaker system, via front-panel headphone connector; rear-panel, balanced analog stereo; or AES-format digital output.
The AERO.air 10-channel Transmission Loudness Manager ($18,250) is based on the company’s first- and second-generation DTV audio processors. The third-generation AERO.air is equipped with multiple loudness controllers, dual upmixers, metadata management, and full-time two-channel downmixing to support legacy stereo or analog paths. Built-in AutoMAX-II processing detects incoming audio and automatically upmixes only when necessary.
Neural Audio’s Neural Loudness Control (NLC, $8995) is an advanced loudness-leveling technology that accurately measures and regulates the perceived loudness differences in audio. NLC works by mimicking human perception of audio and providing tight control of loudness by detecting spectral and density differences, interchannel relationships, and temporal overlaps within the audio signal. It applies the appropriate gain or attenuation to the audio to achieve a user-defined loudness level. If NLC is used ahead of an AC3 (Dolby Digital) transmission, the target loudness level will also match the dialnorm metadata information, providing viewers with a consistent audio experience.
TC Electronic’s LM5 Loudness Meter for Pro Tools HD ($995) displays real-time loudness and loudness history and true-peak level that comply with the new ITU BS1770 international loudness-measurement standard. Audio history is displayed using TC’s proprietary “Radar” scope. Rotation speed is user-defined from 1 minute to 12 hours. The LM5D version ($1,495) has the same functionality as the LM5 but adds two long-term universal descriptors: center of gravity and consistency.
The P2 Level Pilot ($3,595) is a single-rack-space stereo or dual mono loudness controller featuring both 24-bit analog and AES-3 digital I/O with total bypass as well as a five-band compressor and inter-sample peak limiter.
The DB4 DTV processor ($10,995-$13,995) is a dual-engine 2RU processor and can be ordered with SDI and/or AES-3 I/Os. I/Os are expandable to 16 channels of AES-3 or embedded audio. Each of the DB4’s engines can process stereo, dual mono, or 5.1. Units running V2.0 software include TC’s exclusive LM5D Loudness Meter. The DB8 DTV processor ($14,995-$16,995) is a quad-engine 2RU processor with the same I/O capabilities as the DB4 but double the processing power.