For years, end-to-end system testing of digital audio in broadcast chains involved large, clunky, pieces of equipment. Bring multichannel and coded audio into the picture, and this became even more complicated. Devices such as the Dolby® DM100 made this a bit simpler, but are now obsolete.
The Linear Acoustic® MT2000™ Multichannel Bitstream Analyzer fills this void, meeting the need for an updated device capable of analyzing audio in multiple formats, carried via multiple interfaces.
“We saw a need in the marketplace for a modern bitstream analyzer and test generator that is very portable and powerful,” says Larry Schindel, Director of Technology for Linear Acoustic. “Knowing firsthand the types of problems a broadcast engineer might encounter certainly served as inspiration for what features to include.”
The MT2000 analyzes audio streams containing PCM, Dolby Digital Plus, Dolby Digital, and Dolby E, and can optionally decode those Dolby formats. It also generates test signals and can output them as PCM or in Dolby coded formats, and is capable of analyzing input streams while generating test signals. Larry points out this leads to being able to perform some advanced testing, such as system latency measurements. “It generates a special signal and outputs it into the system the engineer wants to check. When they bring the system output back into the MT2000, it tells them how long the signal takes to get through their system.” This type of testing facilitates the ability to ensure audio and video are synchronized through the plant. The MT2000 can also generate an A/V Sync test signal that the engineer can then inject into their system to visually check their timing calculations and settings for A/V sync.
The inputs and outputs support modern professional broadcast and consumer interfaces, including AES-3, SDI (HD- or SD-), TOSLINK™ optical, and optionally MADI, DVB-ASI transport streams, and even HDMI™ input. This wide array of audio sources – notably SDI, which carries uncompressed video with 16 channels of audio for picture and sound in one connection, and HDMI, the interface of choice on the consumer side – makes the MT2000 quite the versatile tool.
The ability to measure and quantify errors in the bitstream at both the AES-3 and coded audio (SMPTE 337M) layers, measure Dolby E line position, display Dolby metadata, and measure loudness following the ITU BS.1770 specification enhances the feature set even further.
“It’s a very flexible product,” notes Larry. “It’s not designed to sit in any one place in the broadcast chain. It’s meant to be used by engineers walking around to analyze and troubleshoot audio streams at all different points in the broadcast chain.”
The MT2000 can also verify that audio is embedded into the proper channels and is properly encoded. And for any purpose you use it for, you can listen either via the built-in speaker, or plug in your headphones to listen more closely – a huge plus in the sometimes noisy environment of a television production facility or machine room.
Clearly, the usefulness of the MT2000 is above and beyond that of an average audio analysis tool. “It’s meant to be carried around the facility,” Larry adds. “This should be in everybody’s toolbox… Remote trucks should have one, production studios should have one, Engineering Departments should have one… This is an essential piece of audio test and measurement equipment brought to you by passionate audio experts. It’s as useful to an audio engineer or technician as a multimeter is to an electrician... It's the Leatherman® of audio engineering tools.”
With its wealth of applications, the MT2000 really is the ultimate multi-function tool for today’s broadcast engineer.