Surround at Work - Part 2

Here's an odd collaboration: Alison Krauss & Union Station, a group that's embraced bluegrass, one of the oldest forms of American music, and Super Audio CD, one of the newest and most advanced music formats. Roots-friendly Rounder Records, Krauss's label since she was 14 years old, and high-tech Sony might seem unlikely bedfellows as well, but their joint multichannel recording project works - amazingly so.

Fiddler/singer Krauss has enjoyed solid success for many years, picking up 13 Grammy awards along the way. But her contribution to the astonishingly popular O Brother, Where Art Thou? soundtrack brought a brighter spotlight. Along with this new attention, the pure sound she can achieve with her band made them ideal candidates for the first nonclassical concert recording made specifically for multichannel SACD, Alison Krauss & Union Station Live. Krauss feels that surround offers a new perspective on her music. "After hearing stereo my whole life," she told me, "surround makes it three-dimensional. That can be pretty intense."

The historic Palace Theater in Louisville, Kentucky, dating from 1928, was chosen for the recording. The grand dame of the city's theater district is spectacular both visually and sonically. Lavishly decorated to resemble a Roman courtyard, it's a spacious hall with seating for 2,800. But a large balcony and intricate detail work help give it a warm, intimate sound. In this setting, two concerts were not only recorded for SACD but videotaped with high-def cameras for an HBO broadcast and a DVD-Video release.

The concerts were magnificent. Krauss and Union Station - acoustic guitarists Ron Block and Dan Tyminski, Dobro player Jerry Douglas, and acoustic bassist Barry Bales, augmented by percussionist Larry Atamanuik - played a wide selection of favorites. Each member was given a chance to shine, particularly on some of the instrumentals. And the band played as flawlessly live as their studio recordings suggest. Many groups are beholden to the studio, relying on take after take to get it right, assisted by electronics to correct or mask pitch and timing problems. Krauss said she grew up thinking she had to kill herself to get a studio performance absolutely perfect. But her dedication has obviously paid off, since she and the band were dead-on two nights in a row. The resulting SACD isn't the product of studio trickery. This is the way they sound when you hear them live.

Producing the concert in surround was exciting for the band members. "The way music is at its best, especially the kind of music we do, is when everybody is sitting around in a circle just playing," Bales remarked. "If we can get this recording to approach that same kind of feel, then that's great." Krauss said that when she first heard music mixed in surround, it was "pretty overwhelming, in a wonderful way." Asked if she had any concerns about her fans embracing this high-resolution surround sound format, she said she wasn't worried. "A music fan is a music fan, and good music is just good music."

Bales added that the band tries to be "on the forefront of what's going on. Just because we play bluegrass doesn't mean it shouldn't be recorded in the best format available. The more lifelike the music can be, the better. And what better way to do that than in surround sound."

The same set list was used for both nights so the producers would have two complete recordings in the can. After the shows, everyone in the band was given CD-Rs of rough stereo mixes so they could decide which night's performance of each song they preferred. The band then decided what would make the final cut. And in the end, some of the songs were edited together from the two concerts to get the definitive performance.

The recording was made with 32 microphones, including one for each of the vocalists and one for each instrument, with four stereo pairs distributed throughout the theater to pick up the audience and the hall ambience. The musicians' mikes were fed into three banks of eight-track hard drives, and the audience mikes went to tape machines, for a total of 32 tracks in all.

Block, who plays banjo in addition to acoustic guitar, faced an interesting dilemma. While he usually works with one microphone for his vocals and another for both of his instruments, he now had to use three - one each for his vocals, guitar, and banjo. Since the other two mikes were positioned on either side of the vocal mike, Block had to lean one way while playing guitar and the other while playing banjo. It might not have been very comfortable, but it made for a better recording.

Capturing a live concert in surround required some special considerations. A mike picking up sound from another musician nearby on stage or through the monitors is usually masked in a stereo mix. But this kind of leakage, or "bleed," becomes a more critical issue when the musicians are placed throughout a sound field for surround. Recording engineer Gary Paczosa had asked everyone in the band to be aware of his or her position relative to their microphones; the closer they stayed to them, the better the separation would be. But the band balked, feeling the restriction would hurt their performances, so Paczosa had to fix any leakage in the mix.

As Krauss pointed out to me, the music had to come first: "The only concern is making something to be proud of."

I sat in the audience for the first night's performance, and then in the audio truck for the second night. When Paczosa asked if I wanted to hear the "on the fly" mix he was doing in the truck, I was intrigued. Could the performance sound better there than it did in the hall? Heck, yeah! As is normal in a concert, the sound in the hall was running through all sorts of amplifiers and equalizers on its way to the house speakers. But the signal in the audio truck came straight from the mike preamps through the recorder and into the console.

The recorded sound had a breathtaking sense of air and space. Bluegrass allows Sony's Direct Stream Digital (DSD) technology (used to record many SACDs) really shine - particularly on the songs that are spare and exposed. Paczosa was especially glad that the technology's resolution meant he wouldn't have to worry about the wide dynamic range of Krauss's voice. And he also wouldn't have to worry about changing the sound levels throughout his mix. "Analog recording doesn't work, because as you adjust the playback levels, you also vary the tape hiss," he said. "And I don't like to compress Alison's voice. On the whispery stuff, DSD keeps the dynamic range and captures the air."

It was a good thing the band's performances were nearly flawless, since the current DSD technology makes it difficult to do overdubs. Because of this, editing on the SACD was limited to choosing between the recordings of the two performances. Paczosa was able to "fly in" sections of each show. For instance, if a bass line was better in the second chorus of a song, just that track could be copied and inserted into the first chorus.

When I asked Paczosa if he was concerned about these limitations, he indicated that the band's professionalism made overdubbing unnecessary. "Each member is an accomplished musician. They play in tune and they play in time." Krauss, however, had some reservations. Her perfectionism made her a little uneasy with the process. "When you play live, the performance only lasts for a moment, right there in the concert hall, while a recording of it is forever." Tracy Martinson, who coordinated the Krauss project for Sony, summed it up nicely: "Many albums are just so overproduced, with all kinds of effects and added things. Because of the state of the technology right now, you can't really do that with DSD. You need to stop thinking about making an album and start thinking about making music."

Alison Krauss's style of music lends itself well to that philosophy. Classic bluegrass, acoustic instruments, accomplished musicians, and SACD may indeed prove to be the perfect collaborators.