Prior to this year’s broadcast, both stereo and 5.1 signals were made before transmission to the network. But after successful trials at the 41st Annual CMA Awards in November 2007, and other ongoing preparations, the decision was made to create only the 5.1 signal for the Grammy® event, and let the DP563 Dolby Surround and Pro Logic® II Encoder at CBS automatically downmix and derive the stereo signal for the SD broadcast. Another first for the show was the use of the Dolby LM100 Broadcast Loudness Meter to maintain an average mix level that matched CBS’s standard for dialogue normalization level.

Mixing Between Trucks
For monitoring and mixing of the musical performances, an XM/Effanel L7 remote truck manned by engineers John Harris and Eric Schilling sat outside the venue. For the Foo Fighters outdoor performance, another truck was stationed across the street from the Staples Center, with Schilling joining Mark King at the helm for the duration of the band’s set. The feeds from these two trucks were sent to the third remote vehicle, the Denali ND4 production mix truck with Tom Holmes at the controls. Holmes performed the mix of all production elements, including the award announcers and voiceovers, music stems, and audience sound. He was also the last person in the production chain, sending the 5.1-channel Dolby E feed directly to New York. The Amy Winehouse performance was mixed by Tim Summerhayes and sent to the US by satellite and fiber-optic lines. (See the accompanying diagram of the audio production setup at the Staples Center.)

We spoke with Mike Abbott, the audio coordinator for the Grammy Awards presentation, and John Harris about the 5.1-only mix sent to New York. The two raved about introducing the LM100 into the mix chain, and its value in helping the mixers during the live broadcast. According to Abbott, this year CBS decided to create the Dolby Pro Logic II Lt/Rt and stereo downmixes in New York using a Dolby DP563, so only one 5.1 mix, transmitted via Dolby E, would be used for both the HD and SD broadcasts.

“We coordinated with CBS months in advance,” Abbott said. “For any broadcaster we’re serving a feed to, if you emulate their presets and standards, you can be mixing and monitoring on-site using the same formats the broadcaster will be using, and properly configure your signal for broadcast. Our biggest concern for the show is that we’re able to have a mix that’s transparent in all of the possible formats that an end user may be watching in. Dolby provided on-site personnel and products assistance for the broadcast.”

Using the LM100 for the First Time
Abbott went on to talk about the integration of the LM100 into the mix. “We wanted to make sure that, in the L7 truck and off-site production area, as well as in Tom Holmes’s production mixing area, we were able to meet CBS’s transmission standards.” Harris added, “If we made any one big improvement this year, it was in our metering education. With the use of the Dolby LM100, we had a lot better handle on what CBS was delivering to the home. The advances in the sound of the broadcast are largely due to us learning this new way to monitor levels. We really focused on giving CBS’s viewers the best possible presentation as we could without hitting the network’s brick wall.”

For the main music mix, Harris and Schilling turned the LM100’s Dialogue Intelligence™ off and primarily measured content in the Center channel, using it as the starting point to maintain a balance across the remaining channels. “We could make sure that the emotional portions of the music would remain as loud or quiet as they needed to be,” said Harris, “while ensuring the average level of performance was at –31 [CBS’s delivery specification for the dialogue normalization level]. Eric and Tom and I all used the LM100, and over the rehearsal days, we developed a choreography between ourselves, getting a handle on where to place faders. The consistency of the LM100’s performance gave us more confidence during the live Grammy broadcast.

“There’s a lot of perceptual subjectivity that goes on with low-level sound in a big room of how, say, a choir might come out of a fade,” Harris continued. “In the past, getting an average apparent sound level was done by ear and by feel, but now, having the LM100 is invaluable. In the past, we used a great deal of compression to make sure we wouldn’t hit digital full scale. I still have a brick-wall limiter in the chain set at –22, but that’s a lot different from the way we used to use it. At every stage, we can now use much less compression, giving the performance more air.”

Harris and Abbott discussed the mixing necessary to derive the apparent level of a very dynamic performance, specifically citing the duet between Andrea Bocelli and Josh Groban. “It started with a very slow, low, almost ballad/dirge feel,” said Harris, “and it built to a huge crescendo, where they’re panned dynamically left and right. For an arrangement like that, the ear may have trouble finding the sweet spot in terms of the dynamic level. Using the LM100, the final mix came out perfect in terms of the audio levels, and the broadcast delivered every nuance of their masterfully polished performance.”

Abbott concurred: “It’s such a different approach to mixing. With 5.1, if you’re working with a Dolby stream, and you have your monitoring infrastructure with the Dolby DP570 [Multichannel Audio Tool], having an LM100 is groundbreaking.”

Said Harris, “Things get complicated when you bring in the all the end-user possibilities: 5.1, Midnight mode, stereo. Having the Dolby LM100 with the numeric output display, rather than dancing LEDs, was quite a benefit.”

Abbott noted that many networks were adopting the use of the LM100 for live broadcasts, and he was enthusiastic about using it in the future. “I think everybody needs to get on board with this type of monitoring, especially going into February 17, 2009, when analog broadcasting goes away for good.”

Special Amy Winehouse Mix
When Winehouse was initially denied a visa to travel to the US, Grammy engineers swung into action to set up a London feed. According to Abbott, “The fact that we had a satellite remote coming from overseas was unique for the Grammy Awards. As we started going into the engineering to do this, however, we found out the paths were somewhat prohibitive for audio in terms of maintaining the 5.1. On the other hand, we wanted to maintain a constant feed to CBS, with the entire program employing the same channels for continuity.

“We knew we could definitely set up two asynchronous PCM streams to work with. So, in trying to figure out how to send the feed from England, we asked Tim Summerhayes to generate a stream with vocal and dialogue on [the same] stream that we would use as the Center channel, and on the other PCM stream we sent a Dolby Pro Logic II Lt/Rt mix for music and effects. The two streams could be joined on our end to create a convincing simulation of a 5.1-channel stream.

“The key thing that made it transparent was having the vocal as a separate Center channel and not as the center of a Dolby Pro Logic II stream,” said Abbott. “It provided a ‘hybrid’ program that allowed the vocal to shine.”

Overall, the broadcast was a success for performers, producers, engineers, and viewers alike.

Find additional information on loudness and the Dolby LM100 Broadcast Loudness Meter.
Find additional information about the 50th Grammy Awards.

Because the ATSC specification uses Dolby® Digital to encode and transmit the audio on these over-the-air services, every converter box will feature a basic Dolby Digital decoder. Dolby has been working with the NTIA and the manufacturers of these converter boxes to ensure satisfactory audio performance on these products. These precautions have been combined into documentation produced by Dolby Laboratories and made available to all Dolby licensees manufacturing converter boxes.

The new requirements, which take effect on April 1, 2008, will ensure that manufacturers and consumers alike are prepared for the new all-digital era of television in the United States.

To offer 5.1 audio with programs produced in-house, SRG SSR’s post and outside broadcast facilities have been upgraded with Dolby E encoding plus Dolby DP570 Multichannel Audio Tools for monitoring.

See A Guide to Audio for HDTV in Europe for additional information on audio production, distribution, transmission, and set-top box requirements for HDTV.

For more information about our NAB highlights and activities, visit www.dolby.com/events/nab.