Loudness Monitoring: A Product Overview
The issue of loudness, when interstitial content is louder than programming or one channel is louder than another, has been a vexing issue for decades. But recent, and some not-so-recent products, are designed to make it easier for broadcasters and cable networks to deliver an audio experience that won’t have viewers reaching for the mute button. Here is a quick look at some of the more popular products on the market.
Cobalt Digital’s Audio Loudness Meter software (OPT-SW-LM) provides a comprehensive solution for ingest or on-air loudness metering and assessment. With true peak level detection, error tracking and logging, and intuitive interface with touch screen control, Cobalt’s Audio Loudness Meter ensures thorough audio level and LKFS assessment information. The option is ATSC A/85 and ITU BS.1770 compliant. The option operates on select 9000 series cards for openGear, in tandem with the OGCP-9000 remote control panel. www.cobaltdigital.com
The iLM8 Intelligent Loudness Meter helps broadcasters maintain desired loudness level across all audio programming. Key features: standalone operation; eight input channels of PCM AES and optional HD-SDI inputs, with channel mapping for all 16 embedded audio channels; routing of any eight channels of demultiplexed SDI audio to the AES outputs; industry-standard ITU-R BS.1770/1 and DTS Technologies Neural Loudness Measure (NLM) algorithms; simultaneous measurement for 5.1 surround and auxiliary stereo inputs; easy-to-read numerical Measured and Target readouts on vacuum fluorescent display; and bar-graph LED audio-level meters. The iLM8 rear panel includes an alarm port as well as an Ethernet interface for long-term logging, e-mail alerts, and field software updates.
According to the company, the NLC5.1ST measures and maintains desired audio loudness levels simultaneously for 5.1 surround and stereo programs in a single-rack-space unit. The device measures and controls perceived loudness of the program audio using the industry-standard ITU-R BS.1770/1 as well as DTS-Neural Loudness Measure (NLM) and DTS-Neural Loudness Control (NLC) algorithms. The NLC5.1ST then uses the proprietary NLC to apply the appropriate gain or attenuation to maintain the broadcaster-defined loudness level. A set of user-definable alarms can alert an operator of input loss, signal clipping, and high- or low-signal levels referenced to the desired loudness level. An Ethernet interface provides long-term logging, e-mail alerts, and field software updates.
The LM100 Broadcast Loudness Meter, a tool for measuring loudness in real time, uses the company’s proprietary Dialogue Intelligence algorithm developed specifically to measure the perceived loudness of dialogue. The LM100 uses ITU-R BS.1770-1 as its core measurement algorithm; users can also select Leq(A). The unit can determine the unweighted peak and a range of other information about the signal. It 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 DP600 Program Optimizer is an audio platform that provides a file-based workflow solution for loudness correction, audio conversion, and upmixing. It supports the ITU loudness algorithm and Dolby’s Dialog Intelligence loudness normalization and provides the ability to encode, decode, convert, or transcode between the Dolby audio formats: Dolby Digital, Dolby Digital Plus, Dolby Pulse, and Dolby E, as well as with PCM, MPEG-1 LII, and various versions of AAC. It also includes a specially designed algorithm for upmixing legacy two-channel audio for 5.1-channel delivery.
The Neural Loudness Control 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 provides tight control of loudness by detecting spectral and density differences, interchannel relationships, and temporal overlaps within the audio signal. After detection, NLC applies the appropriate gain or attenuation to the audio to achieve a user-defined loudness level. If it is used ahead of an AC3 (Dolby Digital) transmission, the target loudness level will also match the dialnorm metadata information.
The Level Magic LT Digital Dynamics Processor automates level control of both transient and AGC signals. Processing is based on the multi-loop dynamic-range-control principle in combination with proprietary adaptive-controlled processing algorithms and enables precise natural control of level-managing devices like compressors, AGC, and limiters without coloration, pumping, breathing, distortions, or modulation effects. Features include analog and AES Digital inputs and outputs; two channels of adaptive audio-leveling processing AGC; transient processor and limiter; adjustable input gain (±20 dB); operation via Web interface (TCP/IP); password protection for view; operator and admin logins; user-friendly presets; GPI interface for parallel remote control; and tally output.
Linear Acoustic is shipping three new monitoring and measurement products. The LAMBDA II, PAMbDA, and PAMbDA II. The 2RU LAMBDA II has new preset recall functions. The 3G-video-equipped 1RU PAMbDA and 2RU PAMbDA feature color OLED displays, dual 3-Gbps HD/SD-SDI inputs, reclocked/downconverted HD/SD-SDI or composite outputs, and balanced stereo analog audio I/O and eight-channel analog outputs. All three units offer optional Dolby E/AC-3 decoding.
The new AERO.qc Audio Quality Controller arrives just in time to supply 20 units for the 2010 Vancouver Winter Olympic Games. It allows users to meter and fix loudness problems in real time and includes the new UPMAX II upmixing algorithm. Options include Dolby E/AC-3 decoding, multiband loudness and dynamic-range control, metadata support, multichannel analog output with speaker EQ, HD/SD-SDI input and output, and dual power supplies.
The LM5 Loudness Meter for Pro Tools HD displays real-time loudness and loudness history and true-peak level, complying 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 has the same functionality as the LM5 but adds two long-term universal descriptors, center of gravity, and consistency.
The P2 Level Pilot is a 1RU stereo or dual-mono loudness controller with 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 dual-engine 2RU processor 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 also include TC’s exclusive LM5D loudness meter. The DB8 version is a quad-engine 2RU processor, with the same I/O capabilities as the DB4 but double the processing power.