MultiMerge at KENS-DT
Sep 1, 2008 12:00 PM, By Jerry Paonessa
Neural Audio's processor solved this station's issue of 2.0 audio interspersed in 5.1 surround programs.
Now we switch multiple HD sources using a 12 × 2 router controlled by GPI from our automation system. And instead of audio from the MMC-100, we now have a final demultiplexer card that separates out three AES pairs for delivery to the unbalanced 75? Neural-THX inputs.
The front panel is clean and uncluttered, with simple status indicators, an LED display showing the type of audio input and a separate audio bar graph for each audio channel. The meters can be switched to show input or output.
Since installation, we have upgraded to the new Neural-THX MultiMerge + Neural Loudness Control (NLC). It has all-unbalanced AES audio inputs and outputs, simplifying cabling to and from our final audio demux and the encoder.
The initial on-air test
When we tested the system for the first time, we were already broadcasting a CBS network show in Dolby 5.1 surround. When we inserted the device into the program stream at the end of a commercial break, the audio processor immediately recognized the Dolby 5.1 audio stream and passed it through without alteration. It doesn't add coloration or change the 5.1 audio. It was completely transparent to the stream.
We eagerly awaited the next commercial break, which was a pod of four national ad spots in stereo delivered by the network and part of the program itself. The MultiMerge reported the input switch to 2.0, but seamlessly continued to deliver simulated 5.1 surround audio in the stream. The viewers did not detect that there had been a change, and surround channels actually reproduced convincing audio from the 2.0 stereo input. This capability was a definite plus in solving our audio problems.
the Neural-THX Surround MultiMerge + NLC system enables broadcasters to simultaneously distribute a 5.1 and 2.0 stereo output.
When we transitioned from network programming to local material, the transition was equally seamless. The local stereo audio remained as full and rich as the network surround content had been, and the spatial distribution of all audio channels likewise remained consistent, delivering a pleasing listening experience. The upgraded model with NLC has level control capabilities to deliver audio with consistent quality and at the correct level.
With no particular adjustments to the final audio encoder, the first audio processor delivered an excellent performance just by virtue of its presence in the program stream. But to make the audio sound its best, we created a preset for the audio processor in the Dolby encoder, which we named Neural 5.1. This preset guarantees that the metadata settings remain consistent, which in turn assures seamless, transparent operation at all times. And since adding the version with NLC, the station team can create individual operating profiles based on a number of presets built into the unit.
The user manual is helpful for getting the desired presets loaded and modified to suit local needs. KENS knew it wanted to retain the open sensation of 5.1 surround audio without too much processing. However, the station wanted control over the sometimes aggressive loudness in a few local commercials. Through experimentation, the team reached a compromise that keeps the commercial blasters reined in while holding on to the dynamic range of the surround audio. Once the target dialnorm was set to -22dBFS, most of the -23 preset was very close to where we wanted it.
Conclusion
The station has experienced only minor issues with the MultiMerge and the MultiMerge +NLC upgrade since installation. (See Table 1.) Like most new equipment, it was necessary to upgrade the firmware to the latest version.
With the MultiMerge + NLC, the station has the best-sounding audio of any DTV station in the San Antonio market. Other stations in the market are forced to switch their audio between 5.1 and 2.0 on a regular basis. The spatial shift when listening to them as they switch is exactly what we avoid by using the this system. It is truly a plug-and-play device, requiring little maintenance or adjustment once configured.
Jerry Paonessa is assistant director of technology, broadcast media, for KENS-DT, a CBS affiliate in San Antonio, TX.
| The needs | Properly integrate local stereo content to a network's 5.1 feed |
| Properly deal with stereo content that the network intersperses through the 5.1 audio | |
| Solve dissonance between stereo and 5.1 | |
| Keep audio properly distributed in the final transmission feed | |
| Deliver consistent audio quality to viewers | |
| The solution | Automatically and seamlessly switch between 2.0 and 5.1 audio content |
| Reside in the digital audio stream between the multichannel output of the master control switcher and the input of the Dolby audio encoder | |
| Employ the Neural-THX Surround MultiMerge + Neural Loudness Control | |
| The results | Automatic detection of 5.1 encoded audio stream |
| Completely transparent, without any alteration to 5.1 audio content | |
| Automatic detection of 2.0 audio stream | |
| Once 2.0 is detected, continues to deliver simulated 5.1 surround audio in the stream | |
| Viewers do not detect switch from 5.1 to 2.0 | |
| Surround channels reproduce convincing audio from 2.0 input | |
| Applies equally to the network's and affiliate's stereo content switching | |
| Seamless and easy integration within standard infrastructure | |
| Easy to use and operate | |
| Delivers consistent audio quality and entertainment experience |
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