The setting of the annual Telluride Bluegrass Festival may be beautiful, but it offers more than its share of challenges to the audio team producing the event.

In the past few years, there's been a growing interest in bluegrass and roots music, with films like the Coen Brother's 2000 release, O Brother, Where Art Thou? and younger artists like Gillian Welch and Allison Krauss drawing increased attention to this sublime music. And while there are hundreds of folk music festivals held year-round throughout the country, credit should be given to a festival that has become something of an institution in the bluegrass community.

The Telluride Bluegrass Festival is set in a beautiful boxed canyon that can pose problems for the technical staff.

Held every June at Telluride Town Park in a lovely box canyon in the Rocky Mountains, the Telluride Bluegrass Festival (TBF) is one of this country's treasures. Located close to 9,000 feet above sea level, the event provides a real breath of fresh air for audiences who travel from around the world to gather and enjoy the music. Organized by Craig Ferguson of Planet Bluegrass of Lyons, Colo., the festival is truly a cooperative labor of love between the performers, the fans and the technical staff.

This year, twenty-eight acts took to the stage over the course of four days, with several notable musicians including Sam Bush, Emmylou Harris, Linda Ronstadt, Del McCoury, David Grisman, Bela Fleck & the Flecktones, Lucinda Williams and the venerable Ralph Stanley & the Clinch Mountain Boys. The organizers' eclectic blend also included the likes of Sacramento's Cake as well as Bay Area local Ben Harper. Sold out weeks in advance, an audience that peaked around 12,000 enjoyed the festival from the late morning ‘til the midnight hour.

Preparing the Audio System

To provide both the sound and lighting systems for the festival, Skip Kent, stage manager for TBF, contracted Audio-Visual Headquarters Show Solutions (AVHQ) of Los Angeles, Calif.. Known primarily for handling large corporate events nationwide, AVHQ also does sound system design, lighting and video production for large-scale special events and concerts. AVHQ's system engineer Mitch Hodge, who has more than a decade of experience working at TBF, used JBL's award-winning VerTec line array for this year's festival.

AVHQ recently made the purchase of a VerTec line array to include in their inventory. As more corporate clients and touring acts had been requesting line arrays, it was a logical step to make the investment. With the assistance of Raul Gonzalez, JBL's touring products manager, Hodge created specifications for a system that would be powerful enough to handle the requirements of the festival and meet with the approval of Skip Kent and the Planet Bluegrass family.

In the weeks leading up to the festival, Hodge and Gonzalez worked closely together developing scenarios for the working system. Hodge created AutoCAD models that were aided by Gonzalez's VerTec-specific line array calculator in Microsoft Excel. With basic measurements of field size, distance from stage to delay to tower, height of scaffold, etc., they were able to simulate and predict what the response would be like. After reviewing options, Hodge opted for two articulated, twelve-box deep arrays of JBL VT4889s per side for the mains, with eight JBL VT 4880s per side for subwoofers.

“It's a pretty wide stage,” says Hodge, “so we had to put the arrays about 86 feet apart.”

While having the arrays so far apart helped in providing plenty of gain before feedback, proper coverage in the front could have been an issue. Hodge brought in eight Apogee Sound AE2s for frontfills just to make sure the premium VIP area would be taken care of.

“Actually the line arrays covered the insides nicely all the way down close,” says Hodge. “We tilted them just a touch onstage, and then I filled the offstage area with the horn-coupled Meyer Sound MSL-4s [which are 40° boxes horizontally] and they worked very well.”

Given that winds of up to 70 mph have been known to come out of nowhere in the boxed canyon, the job of rigging the system was a critical one. While Whitehouse Staging out of Phoenix, Ariz., supplied the material for the scaffold towers, John Setser was brought in as chief rigger to make sure safety issues were covered. Each of the VT4889s weighed about 160lbs., including the rigging system on the boxes. With the rigging on the box, no additional straps or other mechanisms were needed to articulate the array and the weight was kept down. Each array weighed in at around 2000lbs., with two, one-ton chain motors used to perform the 42-foot hang. Once they were in place, straps were employed to secure to clusters so they wouldn't sway in the wind.

The end of the field at Town Park is around 400 feet, so at about 240 feet from the stage there was a delay ring of four Genie T225 towers, each with three JBL VT4889s. As a precaution, Setser fixed waterbarrels and ballast supports to each delay tower since they were susceptible to twisting in high winds.

Fine Tuning in High Country

Collaborating with Gonzalez, Hodge time-aligned and equalized the PA and all the delay towers, and compared FFT data from both Meyer Sound's SIM II and JBL's SMAART systems. Six Brüel and Kjaer 4007 microphones placed throughout the audience to gather data permitted Hodge and fellow system engineer Mark Miceli to make judgment calls on how to change the system EQ during the twelve-hour period.

“One of the interesting challenges at Telluride is the environment being at 9,000 ft.,” says Miceli, a research scientist specializing in acoustics at the University of Arizona. “The altitude density changes the physical response of sound — especially how the low-end of the system performs. It creates what I'd call a real ‘swimmy’ condition.”

The other challenge was that the environmental conditions would change radically. Between the hours of 5 and 7 p.m., the temperature could plummet from 80°F to 30°F within fifteen minutes.

“What made it interesting to us was the thermal stratification,” continues Miceli. “A warm layer of air above the audience would have a much colder air pushing down on top of it. This would end up causing a ‘lens effect’ for the high-end frequency, similar to how a mirage works optically. Sound is trying to pass through a non-homogenous area. With different temperature layers in the air, the propagation rate varies as sound travels through the thermal layers. In effect, this causes the sound to bend.”

The 40-foot wide proscenium of Fred Shellman Memorial Stage. The main VerTec arrays hung about 86 feet apart with Apogee Sound AE2s providing frontfill for the VIP section.

With the temperature quickly dropping, the sound system would start to re-aim itself. “Even the untrained ear could hear the phase shifting,” says Miceli. “It sounded as if someone had a huge pan pot sweeping the system left and right.”

Using benchmark curves established and saved to computer during the initial FFT measurements, Hodge and Miceli steered the system through the transitional time as front-of-house engineer Kevin Hartman mixed the show. “The higher frequencies didn't change very much but the low-mids between 160Hz and 300Hz would exhibit a shift,” says Hodge. “There's typically a peak of energy in that range and that peak would get lower as the temperature dropped. We've been using SIM II since 1994 to track the changes in the system as they occur, and we simply adjust the center frequency of the specific filter to follow this anomaly.”

Stage Treatments

At several TBFs, Miceli has done a lot of work on the stage acoustics. The Fred Shellman Memorial Stage is about 20 to 30 feet deep, with a 40-foot proscenium opening — and it used to resonate horrendously. Doing test measurements to get the signature of the space, Miceli identified the resonant nodes of the stage and custom designed some QRT diffuser panels using Dr. Peter D'Antonio's flutter-free molding. These he used to break up reflections coming off the side and rear walls.

Since there was a hard, plywood deck for the ceiling, he hung 50 two-by-four-foot Sonex-type foam baffles. To help prevent bad reflections, he worked with the carpenters to minimize parallel surfaces and had them slightly angle the back wall when they put the stage together. Miceli also had flooring put down on top of the stage — Net Well's dB Mat, a barium-impregnated vinyl with a 1/8-inch backing on it that carpet was rolled on top of. As a final touch, spaces underneath the front of the stage were also filled with bass traps as well as bales of hay.

With 31 acts and no sound check to speak of, being the mixer for the front of the house wasn't an enviable position. Even with Skip Kent providing the mixer rider information for many of the large, established acts, a lot of the acts formed for Telluride. “Those requirements we often didn't get ‘til the day of show, sometimes minutes before the set,” says Kevin Hartman. “This year, AVHQ provided an intranet setup where a stage laptop talked to my laptop. As soon as the info was ready, I could look at the input list and see what the next act was going to require, and print it out.”

Since set changes were so quick, any time-saving device helped to streamline the work — such as multi-pin, quick-connect snakes for the drum riser so the next kit could mic up offstage.

Also, artist riders were reviewed so that a consistent group of microphones could be assembled. This helped make the transition to each act as smooth as possible, since several channel strips would remain similar from set to set. Of course, they'd swap out to accommodate specific artists who brought along their favorite microphones.

“Del McCoury used two large-diaphragm condensers onstage and they'd stand around the microphones and play like they're on the porch,” says Hodge. “It was a great sound and I love that style.” Several condensers also are used to capture mandolin, guitar and fiddle, too. “Grisman likes his Neumann KM184s, so we'd put those up for him,” adds Hartman. “My preference would be to make it an all-Neumann festival.”

Located 105 feet away from the stage, Hartman mixed performances on a 52-input Yamaha PM4000 with outboard rack including BSS, Eventide, Klark-Teknik, Roland, TC Electronic and Yamaha processors. As for monitoring, mixing duties were divided between Jeff Wetherby and Glenn Utter. Similar to the front of the house, a 52-input Yamaha PM4000 console was used, with 18 Meyer UM-1 for the wedges and three Meyer Sound MSL-3 for sidefill. If artists preferred in-ear monitors, there was a breakout box stage left so they could get power and feed the monitor console.

Telluride Bluegrass Festival is not only a reunion for thousands of fans, but also for a very dedicated technical and operational staff. All people interviewed for this piece commented on the bond shared by the technical team that keeps returning year after year. “It's the same guys for as long as I've been there,” says Miceli. “The festival's staff are really the closest thing to family — we all stop what we're doing to go to Telluride.”

Stage manager Skip Kent clearly respects the group that travels from all over the country to work with him at Telluride. “I was kind of thrust upon the crew and some folks weren't too happy about it. But ultimately everybody was happy to be part of a great team… and they are a great team.”

Alex Artaud is a musician and sound engineer based in Oakland, Calif.

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