As the last strains of a classic Mozart divertimento drifted into the night, three members of the Baltimore Symphony Orchestra took a bow to resounding applause.

Then they walked offstage - not into the green room at Meyerhoff Symphony Hall, but into the crowded living room of Hillen Smith, an 84-year-old impresario in red plaid pants.

So ended 24 years of an extraordinary hidden concert series in a cavernous Roland Park home - where fine musicians played by lamplight for next to no money, patrons sat on mismatched metal folding chairs, and the "emergency exit" signs were lettered by hand. The only admission price was a donation to one of four nonprofit organizations, to be dropped in a glass bowl.

Slowed by health problems and fatigue, Smith has sold his Woodlawn Road home and plans to move to a retirement community. Weeks ago, he announced that Monday's performance would be the last.

"This is a happy occasion," said Smith, greeting his last 100 guests with trademark throaty shouts of exuberance. But most of those in attendance were already in mourning for the end of the music.

"I'm so sorry," said Louise White, former director of public relations at the University of Maryland, Baltimore County, and a good friend of Smith's. "I don't think I'll ever listen to chamber music again with the same feeling, the same intimacy that has been created here."

As in concerts past, coats were hung in a back bedroom. Wine was sipped from plastic glasses, and intermission featured Smith's legendary chicken salad, along with appetizers and desserts contributed by those who came.

Smith, who handled sales and advertising copy for U.S. Fidelity & Guaranty Corp., moved into the 3,700-square-foot, wood-shingle house with his first wife in 1948. The concerts began 30 years later when Smith, then divorced, attended a Pro Musica Rara concert at Loyola College.

Smith was entranced by the intimate style of the music. In talking with the musicians, he learned that they would be happy to play a house concert. Smith had already been giving pre-concert dinner parties for small groups headed to the symphony. Why not bring the concert to the party? And while he was at it, why not raise money for the symphony?

Soon, Smith, an accomplished ballroom dancer who also loved jazz music, was sponsoring nearly a concert a month. Attendance was by invitation only. The circle gradually widened from Smith's friends to their friends, and the mailing list for concerts grew. Those on it would receive word of the latest program on a small typed notice, always headlined: "Hillen Presents."

Smith's grand house, built in 1900, was part of the attraction. In summer, he would throw open the windows and set chairs on the huge wraparound porch, with more on the lawn. In colder weather, guests stayed inside, admiring the rich oak trim and crossbeams that Smith refinished himself.

Even after a second divorce in the early 1990s, Smith kept the house for the concerts. He rented out the top two floors. On the first, he began to leave the folding chairs in place, ready for the next performance.

But this year, Smith concluded he could no longer keep up his monthly entertainment.

He reserved a space at Edenwald, a Towson retirement community. He was wistful but philosophical, saying that perhaps he could start up a concert series in his new home.

"It's been a wonderfully happy life," Smith said. "It's the festive atmosphere that's been the most exciting."

His house sold quickly, but Smith sought time for one last concert.

All 96 seats were reserved within six days. Still more people showed up unannounced Monday, standing behind posts and peering in from the kitchen for one last listen.

The back of the program featured pictures of Smith cutting the rug with an unidentified woman, and wearing a festive hat. "Hillen, we thank you for 24 wonderful musical years," the program said.

Smith estimates his concerts have raised about $300,000 for charity. In recent years, the performances have benefited one of four organizations: the symphony, the Baltimore Chamber Orchestra, Our Daily Bread soup kitchen or the Franciscan Center.

Smith typically paid the musicians a flat fee of $200 - to be split no matter how many of them were on the program. The money, plus some for the chicken salad and mailings, came out of the chosen charity's take.

But prominent local musicians kept coming back. Among them was Qing Li, the symphony's principal second violinist, who has played at Smith's house for nine years and performed at his final concert.

"It has its obstacles," the violinist acknowledged, as she wedged into the crowded back room designated as the musicians' warm-up space. "But what's nice is they're a really good audience. It's a very intimate and warm atmosphere."

Symphony violist Karin Brown remembers playing during a summer thunderstorm, when the wind and rain whipped past the patrons on the porch and through the open windows to scatter her music. Fortunately, she was playing pieces by Bach, Hindemith and Brahms, with drama suited to the occasion.

But episodes like that were worth it for the fun of being up close with an audience that is far removed in a symphony hall, Brown said. "There's community oozing into you."

That community was in great evidence Monday, which brought many tributes to Smith.

Symphony president John Gidwitz presented Smith with a picture of the orchestra covered with the signatures of its members, with maestro Yuri Temirkanov's nearly undecipherable autograph smack in the middle.

Mayor Martin O'Malley issued a citation, and friends wrote and read poems - including one called "Hillen's Hips," in honor of the host's dancing prowess.

The poem was composed by Randy Barker, a neighbor and internist at John Hopkins Bayview Medical Center who said he was "absolutely crushed" that the concerts were ending.

"We'll walk around this neighborhood and wonder, where's Hillen?" Barker said. "Where are Hillen's hips?"

White said she could not count the number of friends she had brought to the concerts over the years. "I always like to think about all the music that was heard in this house," she said.

When the final performance was over, White went over to Smith, who was tidying the lamps and straightening the curtains, and told him she was going - one last time - to sit on his porch.

That she did, her breath freezing in the air as she hoisted herself onto a ledge. She reminisced, in the cold, about the notes that drifted magically from this house in summers past.