Dark Star Orchestra is, to borrow the title of an oft-performed Grateful Dead song, going down the road feeling bad.

In April, keyboardist and vocalist Scott Larned, who was also a founding member of the acclaimed Grateful Dead tribute band, died suddenly of a heart attack. He was 35.

For fans of DSO, Larned’s passing is eerily familiar: The Grateful Dead lost three of its keyboardists to untimely deaths over its 30-year run.

Devastated but determined, DSO keeps on truckin’. In Larned’s stead is keyboardist Rob Barraco, a veteran guardian of the Grateful Dead canon who has spent the last few years playing keys for both The Dead (the Grateful Dead sans Jerry Garcia) and Phil Lesh and Friends, the band of Grateful Dead bassist Phil Lesh.

”Barraco’s having a blast,” said Rob Koritz, one of DSO’s two drummers. ”When he comes out with us, he plays (the songs of the Dead) in a more purist sense. Phil’s band plays them in a more avant-garde sense.”

Known for its faithful renditions of the Dead’s music, as well as song-for-song replications of past Dead shows, DSO performs Monday at the Midtown Ballroom in Bend (see ”If You Go”).

DSO is not a cover band, rehashing old songs in the hopes it will attract enough attention to start performing its own material. Rather, DSO works to recapture the essence of the Dead, and has no ulterior motives in its performance. It strives to get everything right when it re-creates one of the nearly 2,000 shows the Dead performed between 1965 and Garcia’s death in 1995.

”It’s not note-for-note, but there are certain things we want to make sure show up because they are so vital to that particular performance,” said Koritz, 37, who fills the role of Dead drummer Mickey Hart.

”Style, tempo, arrangement and tone; those are the big four,” Koritz said.

Picking what Dead shows to mimic is up to Rob Eaton, the band’s rhythm guitarist (who even looks like Dead rhythm guitarist Bob Weir). According to Koritz, Eaton has several critical questions to answer in order to winnow the right show.

First is a venue’s stage size. If the stage is two small to hold two drum kits, the Beast (a large drum apparatus the Dead created), a Hammond organ and six musicians, a la the Dead during the 1980s, Eaton will consider one the Dead’s shows from the early 1970s, when there was only one drummer in the band, no Beast and no organ.

Because DSO has two drummers – Koritz is joined by Dino English – the two take turns manning the trap kit when Eaton picks a one-drummer show.

Next comes DSO’s history in the town they are playing. If they played a ’70s show last time they visited, then the next time they will try to do something from the ’80s, Koritz said.

The third criterion is what shows the Dead played when they visited the town, and fourth is what shows they played on the same date that DSO will be playing.

How could they possibly figure this stuff out? Koritz said they are helped by DeadBase, a compendium published by a small press in New Hampshire that cross-references all of the Dead’s shows.

”Everyone in the band has to have one,” Koritz said. ”It’s our Bible.”

For those trying to decipher what Dead show DSO might play when they visit Bend on Monday, here are some hints:

DSO last performed in Bend in May of 2004, and prior to that was a show in April of 2002. The May 2004 show was a performance of the Dead’s April 10, 1987 show in Chicago, and the April 2002 show was a performance of the Dead’s Feb. 28, 1973 show in Salt Lake City. The Dead never performed in Bend, but they did play on Oct. 10 seven times.

Of those shows, they were in the years 1968, 1970, 1976, 1980, 1981, 1982 and 1994.

Ready to make a guess? There are a few more fine-printlike details to point out. DSO doesn’t perform many of the Dead songs that feature the Dead’s first keyboardist, Ron ”Pigpen” McKernan,” nor do they perform many of the songs that feature the Dead’s last keyboardist, Vince Welnick. Therefore, the range of Dead shows that DSO will re-create spans from 1971 to 1990.

Koritz said the band would like to do more songs that featured the bluesy Pigpen, but it has yet to find a performer who can also sing, rap and play the harmonica like him. Pigpen was the first of the Dead’s keyboardists to die, of complications from liver disease in 1973.

Barraco, however, has been pushing the band in that direction, Koritz said, getting the group to perform some Pigpen songs. When it does, it’s most likely because DSO is playing what Koritz calls an original show. A DSO original show features Dead songs but played in no set order.

”Every once in a while, we’ll just play a bunch of songs we want to play and that opens it up,” Koritz said. ”You can do ‘Dark Star’ into ‘Sunrise’ into ‘Blow Away,’ and that’s fun.”

Koritz estimates that one out of 10 of the band’s shows is an original show.

Following DSO’s stop in Bend, the band will play the Fillmore Auditorium in San Francisco. A popular concert hall for many of the musical acts of the 1960s, including Janis Joplin, Jimi Hendrix, Jefferson Airplane and Miles Davis, the Fillmore also played host to many of the Dead’s early era shows.

As DSO grows – it’s now in its sixth year – the band finds itself starting to play more and more of the same venues the Dead used to play.

”It’s way cool,” Koritz said. ”There’s something about the Fillmore, everything that went down in that building – the energy is definitely still hanging out in the rafters.

In San Francisco, DSO will lose Barraco, who will leave the band for a tour with Phil and Friends. Another keyboardist has been lined up in order for DSO to finish the five remaining dates on its tour, but it is looking for a permanent replacement. Koritz said the band is still reeling from Larned’s unexpected death.

”That’s been difficult,” he said.

Larned left behind a daughter, so the band has set up a college education fund for her, Koritz said. Donations may be made through the band’s Web site, www.darkstarorchestra.net.

Despite the loss of Larned, the band hasn’t lost its inspiration. Along with the remaining members of the band, John Kadlecik on lead guitar and vocals and Kevin Rosen on bass guitar, Koritz said the band is looking forward to returning to Bend. It was in Oregon, Koritz pointed out, that three years ago, DSO jammed with original Grateful Dead drummer Bill Kreutzman. The band played the Dead standard ”China Cat Sunflower – I Know You Rider” together, and the experience was ”absolutely amazing,” said Koritz, who got to play with one of his musical idols.

DSO has also played with Welnick, Weir, Donna Jean Godchaux, a vocalist who performed with the Dead in the 1970s, and Tom Constanten, a pianist who briefly performed with the Dead in the late 1960s.

”We’ve played with every living member of the Grateful Dead but Phil and Mickey,” he said.

Koritz said that the music of the Dead spans generations, whether it be in the form of a band like DSO that is playing music written before Koritz was born, or in the form of multiple generations coming to DSO’s shows. Koritz said that many of the people who attend DSO shows are fans of the Dead, even though they never saw the band live.

”I’d say in certain cities, a majority of the (concertgoers) never saw them,” Koritz said. ”My favorite thing that happens is when we get a grandfather who saw the Dead in the ’60s, a dad who saw them in the ’80s, and a son who is a fan but has never seen them, and they come out together. I love that.”

If You Go

What: Dark Star Orchestra

When: 9 p.m. Monday, doors open 8 p.m.

Where: Midtown Ballroom, 51 NW Greenwood Ave., Bend

Cost: $16 advance, plus service charges, $18 door; 21 and over

Contact: For tickets, Ranch Records (389-6116) or TicketsWest (800-992-8499); for information, 388-1106