For three hours, Joe Nathan sits and watches the Minnesota Twins play ball. Then, the relief pitcher is asked to get three quick outs in the ninth inning. In 2007, the Twins played 1,458 innings. Nathan pitched in 72. Yet if he fails, a victory is lost. He is indispensable to the club.

Imagine now the percussionist perched at the back of the Minnesota Orchestra. He waits in fretful anticipation as the instruments around him furiously exhaust themselves, playing Mahler's Ninth Symphony. Finally, Osmo Vänskä fixes his eyes on the percussion section and gestures for the cymbals. CRAAAAASSSSSHHHHH!!!!!!!!!!

"A Mahler without cymbal crashes just wouldn't be," said Brian Mount, principal percussionist. "There is so much build-up to a climax that only one instrument will do. And if I put the cymbals together badly, I never get that moment back. You're extremely exposed."

John Milton probably didn't have percussionists (or relief pitchers) in mind when he wrote eloquently about those who also serve by standing and waiting. And truth be told, percussionists would bristle at the notion that they only stand and wait, but to the casual observer it does appear they spend lots of time with their arms folded while the violins are furiously bowing.

"When we have public forums, we invariably get questions about the percussion section," said Gwen Pappas, the orchestra's spokeswoman. "Is it really a full-time job for someone to play the triangle? How do they decide who plays which instrument? Why does the timpani player always put his ear on the instrument?"

Jason Arkis, who plays timpani and percussion, took aim at those questions with a feistiness that betrayed his familiarity with the inquiry.

CRASH! BANG! BOOM!

What: Percussion Festival by the Minnesota Orchestra.

When: 7:30 p.m. Thu., 8 p.m. Fri. Also May 29-31, June 5-6.

Where: Orchestra Hall, 1111 Nicollet Mall, Mpls.

Tickets: $25-$83, 612-371-5656 or 1-800-292-4141.

Web: www.minnesotaorchestra.org.

"Unless you come to the orchestra with the frequency that most people don't, you cannot get the full scope of what we do," said Arkis. "I never think, 'I only have two notes in this piece.' I make them the best two notes I can make. They are highly significant."

Beginning Thursday, audiences will get a better sense of the significance of percussion as the Minnesota Orchestra opens "Crash, Bang, Boom!" a three-week percussion festival that moves these natural back benchers down front. This week's program includes Bizet's "Carmen Suite," orchestrated by Rodion Shchedrin, and Rachmaninoff's Symphony No. 3.

The Swedish percussion ensemble Kroumata will join the orchestra May 29-31 in Aho's Symphony No. 11, and soloist Colin Currie is featured the final weekend, June 5-6. Music director Vänskä will conduct the festival concerts.

The indispensable accent

Arkis cited a different sports analogy -- the field-goal kicker -- during a recent roundtable interview with his mates. You wait for your moment in the sun, your hands ice up, the mind begins playing games and then there you are, doing your best to be "subtle and soft yet insistent" on the snare drum. "It's a mental game when you don't play," he said.

Percussionist Kevin Watkins agreed that there is real pressure.

"We've come to think of it as we get the perfect note in the perfect place at the perfect time with the perfect sound," said Watson. "That's what's expected of us."

Watching with a heightened sense of awareness at a recent rehearsal, a visitor noticed how essential even the smallest percussion accents are -- the architectural detail or the crown molding on a cabinet. As assistant conductor Sarah Hatsuko Hicks led the orchestra through Copland's "Appalachian Spring," the personalities of these different pieces revealed themselves: the sharp brightness in the triangle, whimsy in the wood block, and deep emotion of the timpani. The sound of these instruments is disproportionately significant to the amount of time they are played.

Following the session, Mount, Arkis and Watkins muscled their glockenspiel, xylophone, bass drum, snares and tam tams farther across the back rail of the risers in preparation for the concert.

"There was a large space between us and the brass," said Mount. "'Appalachian Spring' has enough tricky ensemble issues that it's nice to be closer to them."

Instrument placement is a big deal to percussionists. Like a theatrical director blocking movement in a scene, Mount spends hours sketching where each piece will be positioned, and who will play which instrument when. Can he hit the snare and in the next instant play the glockenspiel?

For the "Carmen," a player needs to hit the marimba and in two beats do a snare-drum roll. The bongos need to be near the snare drum and the castanets near the chimes.

"Sometimes what you think in your head will work won't, and you have to reshuffle once you get into the hall," Mount said.

Offstage, the three proudly show off tall cabinets, shelves, corners and stairwells stuffed with rows of tambourines and snare drums, tubs of maracas, claves, wood blocks, sleigh bells, cowbells, castanets, ratchets, bamboo wind chimes, marimbas. One shelf is labeled "Junkyard" and another "Crap."

Mount told the story behind large metal chimes that were purchased from a German maker while the orchestra was on tour.

Then there is the Mahler 6 hammer, a huge mallet more sized for driving fenceposts. The hammer is used to bang on a specially constructed box -- at least once every three years when Mahler's Sixth is performed.

Mysteries of the art

Peter Kogan, the orchestra's principal timpanist, says people often wonder if he is bending down to smell the large drums, or perhaps to kiss them. No, he is putting his ear to the skin to see if the instrument has gone out of tune during a concert. Particularly with drums that use calfskin or goatskin, the dryness in the hall or the heat of the lights can affect the pitch. Even plastic heads can lose their tune. And yes, the timpano does have a pitch, just like the bass or tuba.

So Kogan needs to pick the right spot to listen and then slowly re-pitch -- which is much more art than science.

"Percussion is all about tricks," Watkins said.

Take the bass drum, for example. There are several different mallets to produce a specific resonance. You can hold a towel on the drum and then release it. Or press your leg against the drum, or wrap a towel around your knee and then press against the drum. The ear can detect all these tweaks in the articulation or the sustained length of the sound.

Then there is sandpaper. Arkis runs back to the percussion cabinet and brings back a tambourine that has a thin strip of sandpaper affixed in a semicircle around the outer edge of the instrument's skin. He runs his finger along the gritty surface and the natural friction rattles the tambourine in a sustained and consistent manner. Mount mentions that he likes 150-grit sandpaper while Watkins says he goes with 220.

"I spend a lot of time in the hardware store," he said.

There is also a downside to this gambit.

"You can sand off your fingerprints," Mount said.

Spoken just like a pitcher looking for an edge with his curveball.

Graydon Royce • 612-673-7299