Austin City Limits Live: A Connected New Venue

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Type: Article, Report or Whitepaper

Topics: Live Events

Date: December 2011

By Dan Daley

Texas is certainly a big place, but Austin, all things considered (like, it’s the state capital), is a relatively small town. That worked in favor of the folks who collaborated on the creation of ACL Live, the new home of the long-running PBS hit show Austin City Limits.

ACL Live opened in February 2011, adjacent to a new W Hotel and every bit as sophisticated. The last solder patches were still warm when the first notes came off the stage on opening night. The project’s tight construction schedule was helped by the fact that both the PA system installer, Big House Sound, and the broadcast integrator, Beck Associates, are Austin-based. Moreover, PA system designer and acoustical consultant Steve Durr from Nashville, Tenn., has spent so much time in Texas on projects that include recording studios for Willie Nelson and the Aztec Theater in San Antonio, that he’s pretty much an honorary Texan.

ACL Live (a.k.a. the Moody Theater, when it’s used as a non-broadcast concert or event space) came with implicit challenges for both audio and video. It’s one of the rare facilities that have to serve as a live-performance venue while also meeting broadcast recording criteria.

“We have a long relationship with KRLU [the PBS affiliate that originates the show],” says Roy Kircher, owner of Big House Sound. “Everyone working on the venue pretty much already knew everybody else, businesswise and personally. It was one big family project. But the best part is that everyone knew what to expect.”

Getting the Sound Right
The house seats 2,750, but the floor and balcony seating are steeply raked, with the furthest seat only 90 feet away from the stage. In addition, the edges of the seating areas are tightly curved inward to achieve an intimacy for broadcast shows. When designing the sound system, the team had to consider that the stage and the PA system needed to be reconfigurable for non-broadcast, live concerts, and that the entire venue was joined at the hip to the W Hotel next door  (where not every guest would want to hear concert sound as if it were in the next room). The key, says Durr, was a combination of adroit acoustics and common sense.

“They were transitioning from a small theater that seated maybe 300 to a space that holds nearly ten times as many people, so the challenge was to keep the intimacy that the show was used to — and that performers and audiences enjoyed — but apply it to a much larger venue,” Durr explains.

After the PA components had been specified by Durr and engineers from Meyer Sound Labs (Austin City Limits has a longstanding relationship with Meyer Sound), Durr used ray-tracing software to predict the spectral characteristics of the acoustics. That determined the amount, placement and distribution of a combination of absorption and diffusion products, including RPG’s DiffusorBlox, an acoustical concrete masonry unit that integrates acoustical control and construction materials, to achieve the necessary acoustical modifications.

“The goal was to get all the frequencies to decay at the same rate, which we achieved,” says Durr. “My first [criterion] for a live performance space is making the artist comfortable on-stage. If the artist isn’t comfortable, the rest doesn’t matter, because it all starts with the music. So the design is meant to let some of the reflected energy off the stage and let the PA get back onto the stage to the artist, to let them feel like they’re in the middle of the music. That’s why the right mix of acoustical materials was so critical. So far, every artist who’s played here tells me that’s exactly what we managed to accomplish.”

Attaching the venue to the W Hotel might have seemed like a straightforward mechanical coupling issue, but it was actually one that illustrated how getting key players involved early made a difference. Durr says that instead of decoupling the entire performance space from the hotel’s outer structure, he chose to decouple only the area of the floor that the stage sits on, using Kinetics springs to isolate the floor from the rest of the structure. That, he says, saved money without detracting from the end result, which, in turn, encouraged the client to give the systems designers a freer hand to pursue technical excellence.

Durr also specified a 12-inch grout-filed cinderblock wall and a second 8-inch wall separated by an air space, to further limit low-frequency transmission, as well as DuctSox, a flexible fabric air dispersion product for HVAC distribution in the performance area, as an alternative to typical metal ducting, to reduce noise transfer. In the end, the design achieved a remarkable NC-30 sound transmission rating.

The main PA system consists of Meyer MILO enclosures flown eight per side under three Meyer HP600 subs per side. This covers most of the room, with 22 Meyer UP4XP ultra-compact loudspeakers used as under-balcony fills. A pair of Meyer UPQ-1P wide-coverage speakers and one Meyer UPJunior two-way speaker are used per side as side-seating fills behind the main arrays.

The challenge lay in flying the system, says Zach Richards, Big House Sound’s installation manager. Because the system had to be reconfigurable for concerts, and because there were no exposed beams for fixed hang points, Big House designed and built a motorized hoist-and-cradle system that could be easily moved from above the rigging grid to raise and lower the PA hangs, which could then be moved to other fly points on the grid. When the venue does need to be reconfigured for non-broadcast concerts using an alternate higher, wider stage (in which case the main clusters are moved back and the front fills repositioned) a DSP system consisting of two Meyer Galileo 616 and one Galileo 408 units is used to reset the time alignment of the speakers for their new location relative to the seating.

To keep the system as flexible as possible, no FOH or monitor consoles were permanently installed. “So many artists travel with their own consoles now that it made more sense to rent in order to be able to comply with all the contract riders,” says Big House’s Kircher, whose company also fulfills ACL Live’s rental needs. But engineers did install multiple snake options to accommodate both analog and digital consoles. For recordings, a custom Whirlwind three-way analog split is used, which includes a Lundahl transformer with an isolated feed to the audio recording suite.

At the Controls
The broadcast audio control room, situated below the video editing suite, is built around an Avid/Euphonix System 5 digital console and a pair of increasingly rare Urei 813 monitors that Durr bought from another venue. The unique touch was part of Durr’s pursuit of an audiophile environment, right down to the Mcintosh tube amplifiers that power the monitors and a Genelec 5.1 surround monitoring system. The audio control room receives a transformerless isolated split from the stage, but its physical isolation is also impressive: The room’s floor is also spring-mounted, with foam perimeter board between the slabs to enhance stability.

Upstairs, Beck Associates installed a video system that is linked by a pair of multiplexed fiber cables running the 2.5 miles from ACL Live to KLRU’s studios on the University of Texas (UT) campus. Among the goals, says Fred Beck, was to mirror the workflow process in both locations.

“Their current workflow is set up to ingest directly into Avid Airspeed ingest and play-out servers, so the way we set them up is that they can send audio and video directly from the venue to the communications center at UT and do the line cuts and editing there, where they already have an extensive server system in place,” explains Beck, whose work on high-level broadcast trucks informed a lot of the systems design for ACL Live, such as the redundancy that broadcast requires. “If we lose a fiber link here, they still have a fully backed-up set of recordings to local XDCAM machines,” he says, adding that the long-term plan is to add editing capability to the Moody facility and, using Gigabit Ethernet connectivity, give the theater’s future editing suites full access to the station’s servers.

In the ACL Live video control room — again, reflecting Beck’s broadcast integration roots — all audio and video recording devices receive a combined stereo and 5.1-surround mix simultaneously via eight channels of embedded audio using an Evertz 32x32 high-definition video router with 96 Xlink outputs. “They’re using eight channels of audio all the time, even in the initial mix, which is pretty unique for music, and it’s all embedded with the video,” Beck says, adding that the lighting and FOH mixing positions in the performance hall also have video feeds from the control room to give the operators a director’s point of view.

SMPTE fiber cabling also runs to about 40 locations throughout the venue, including the green room and dressing rooms, allowing cameras to connect virtually anywhere and send feeds back to the control room. All the sources are connected to the Evertz router “so that anything can go anywhere — literally,” says Beck, including to the Sony digital signage set up in the mezzanine-level lounges and, eventually, into the hotel next door.

Like a handful of other similarly networked live events facilities, most notably L.A. Live in downtown Los Angeles, ACL Live reflects a new social hybrid space that integrates technology, entertainment and lifestyle. But even though the ACL Live venue charts a path toward the future, Austin City Limits — the show that has been a PBS benchmark for quality and been enshrined in the Rock & Roll Hall of Fame — keeps doing what it’s done for the last 35 years: showcasing great musicians that look and sound equally great.