WHEN COLUMBIA'S Merriweather Post Pavilion opens its season this weekend with the ninth annual Capital Jazz Fest, the Washington area's second-oldest summer shed (behind Carter Barron Amphitheatre) will mark its latest lease on life, courtesy of I.M.P. Productions.

The Bethesda-based company, whose principal partners, Seth Hurwitz and Rich Heinecke, are also owners of the 9:30 club, signed a contract in October to book and operate the facility, which is owned by the Rouse Co. I.M.P. promoted shows at Merriweather Post between 1998 and 2002 through an agreement with the facility's then-leaseholder, Nederlander Organization, but after the lease was acquired by Clear Channel Entertainment, Clear Channel chose eventually to book the venue exclusively. Then in July, the very future of the Howard County landmark, which holds 5,000 under its roof and 10,000 more on the lawn, was called into question when Rouse announced plans to convert the open-sided amphitheater into an enclosed, year-round theater and performing arts center. The loss of all those lawn seats would obviously affect the kinds of events held there.

Although Rouse hasn't announced a timetable or unveiled specific plans for Merriweather Post's future, it was known to be unhappy that the venue had suffered financial losses after booking only 19 concerts last year, down from as may as 40 in the pavilion's most successful years.

I.M.P.'s Hurwitz says there likely will be 30 or so shows at Merriweather Post this year, adding, "It's really more about quality that quantity. The problem in the shed business is that there are too many shows and we are really trying not to just do shows. I pass on a show every day. I could have done 100 shows -- that's not the point."

Among the shows he has booked: Indigo Girls (June 19), Dashboard Confessional (June 24), Harry Connick Jr. (June 27), Diana Krall (July 3), 3 Doors Down, Nickelback and Puddle of Mudd (July 20), Counting Crows (July 21), Evanescence (July 24), The Cure and Interpol (Aug. 6), Alanis Morissette and Barenaked Ladies (Aug. 10), Sarah McLachlan (Aug. 11, her only outdoor date), Norah Jones (Aug. 20), Bela Fleck and the Flecktones's Acoustic Planet revue (Aug. 29), and Jack Johnson with G. Love & Special Sauce (Sept. 17). The facility will also host the multi-act Lollapalooza, this year expanded to two days (Aug. 12 and 13) and headlined by Morrissey, Sonic Youth and PJ Harvey on the first day and the String Cheese Incident, Flaming Lips and Wilco on the second. Merriweather Post will split some dates with rival Nissan Pavilion: Dave Matthews and Galactic are at Nissan July 11 and at Merriweather Post July 14, while Kenny Chesney, Rascal Flatts and Uncle Kracker are at Merriweather Post July 10 and at Nissan Aug. 13.

Merriweather Post opened in July 1967 and was designed by acclaimed architect Frank Gehry (the Guggenheim Museum in Spain and the Experience Music Project in Seattle). It's one of the last standing Nederlander-built sheds, along with the Greek Theater in Los Angeles and the Blossom in Cleveland. Over the past few months, Merriweather Post has been undergoing renovations under the supervision of I.M.P.'s Chad Houseknecht and the pavilion's longtime director of operations, Brad Canfield. They include sound, lighting and video upgrades and improvement of the food concessions and the ambience of the grounds themselves.

Houseknecht notes that Merriweather Post "was built in an era when the amenities expected by today's tours were unheard of, and the production values that are now de rigueur were simply unheard of back then. It's a challenge trying to fit in modern video and sound, almost like fitting square pegs in round holes."

"We're going to attempt to affect the sound of the amphitheater," adds Hurwitz, pointing out that the acoustic renovation is being handled by the Walters-Storyk Design Group, a nationally renowned architectural design and acoustic consulting firm that also did the new 9:30 club. John Storyk, a respected acoustic engineer (his first major job was Jimi Hendrix's Electric Lady Studios), has designed "300 custom acoustic panels as part of the Pavilion roof acoustic treatment, which we expect will significantly improve the acoustics of the Pavilion," Houseknecht says.

There also will be a discreet sound system for the lawn by a local company, MHA Audio, aimed at improving the quality there as well ("Most tours don't care so much about lawn," Houseknecht says). And look for what will be the first full-daylight, all-day LED video screens in any summer shed.

There have been improvements over the last decade, out front with the grading of the lawn to provide concertgoers a better view of the stage, and backstage with the loading docks and dressing rooms. Still, says Houseknecht, whose unofficial I.M.P. title is director of ambiance and atmosphere, "we're doing spit-polish renovation of the backstage, and I'm doing some 'Chadwork' to the dressing rooms."

And the grounds, too: Area taggers were brought in to help spruce up the pavilion's information signs and kiosk canopies with what Houseknecht calls " 'real tree' camouflage graffiti, almost a decoupage pattern/stencil effect." And he's installing a sculpture garden around the performance area, including some very large pieces, for "something to do other than just come in and sit in your seat." The works will be mostly by local sculptors.

There is a challenge in that some of the pavilion structures are registered as historical landmarks, and there are some things I.M.P.'s lease does not give the company control over. But, Hurwitz points out, "the facility has not deteriorated, and most of the problems are small and easily corrected. The place is pretty much naturally beautiful."

Hurwitz is also planning to put in "9:32," a special deck that will re-create the spirit of the club's back bar, "a place for the downtowners to feel comfortable out of the sun and in the dark," he explains with a laugh.

Another notable change: I.M.P. replaced corporate food-services provider Aramark with Baltimore's Charm City Hospitality. "We're pretty proud of the food we have at the 9:30," says Hurwitz, noting that "I always look at it as what would I want? We ran into the same thing as at the club, where people said, 'It's just a club!' But why shouldn't you have good food? So we'll have all the staples as well as more interesting things."

Including some things directed at women. "They aren't into eating carnival food," Hurwitz says. "They want real food. More than anyone else, they watch their weight and nutrition, so we now have salads at every stand, and we're going to have sushi, too."

Incidentally, the Sessions concerts that were held downtown near MCI Center two years ago will move to Columbia. The McDonald's Sessions at Merriweather will run every Saturday from July 17 (headlined by Fuel and Evenout) through Sept. 4. Featuring national, regional and local acts, the concerts will run from 6 to 11 p.m. and tickets will be $10 in advance and $15 at the gate (both include parking). Mad Bookings & Events, which does Sessions in home-base Atlanta and Nashville, was looking for a larger venue and a place the company could have a little more control over (and not have to build a stage in a day) and could draw from the Baltimore market as well. Other shows include Twista (Aug. 7), Live (Aug. 14).

CALLING ALL GUITARISTS

Washington is renowned as a guitar town (we claim Roy Clark, Danny Gatton, Roy Buchanan, John Fahey and Link Wray, among others), but Baltimore is currently the center of the guitar universe as Towson University hosts the First World Guitar Congress through Tuesday, with more than 40 world-renowned guitarists from the worlds of classical, jazz, rock, country, blues and flamenco. Among them: Les Paul (honorary chairman of the congress), Jim Hall, Dick Dale, Albert Lee, Pat Martino, Tony Rice, John Scofield, Andy Summers, Ralph Towner, Howard Alden, Derek Trucks and Robert Lockwood Jr. Events include concerts, clinics, master classes, symposiums and lecture-demonstrations. Evening concerts will be held at the Towson University Arena, Stephens Hall Theatre and the Joseph Meyerhoff Symphony Hall in downtown Baltimore For a complete schedule, go to www.towson.edu/worldmusiccongresses/agenda.htm.

Tickets covering admission to all concerts, clinics, master classes, symposiums and exhibits -- more than 90 events -- are $385 ($335 for students). A daily registration ($75) does not include tickets to evening performances. Tickets to individual concerts, ranging from $25 to $40, may be purchased only at the Center for the Arts ticket office at the University Union on the days of the events or on the Web. Tickets for concerts at the Meyerhoff Symphony Hall may be purchased only at the Meyerhoff ticket office or on the Web. There are also more than 60 exhibitors, guitar, amplifier and string manufacturers and luthiers, guitar publications and studios. The exhibition space, in the University Union, is open to the public at no charge.

The first full-daylight video screens in any summer shed aim to improve the view from lawn seats. Seth Hurwitz, from left, Chad Houseknecht, Brad Canfield and Rich Heinecke check out a dinosaur sculpture in the new sculpture garden at Merriweather Post Pavilion.