These are terrible times for the prestigious Los Angeles Chamber Orchestra. Kent Twitchell's huge mural of its musicians may look very sturdy from the Harbor Freeway, but the organization billing itself as "the orchestra of the 21st Century" has been battered by the city's economy, riots and earthquakes alike.

As the orchestra celebrates its 25th anniversary, it does so with nearly empty coffers. Concert-goers found last weekend's concerts at Royce Hall and Ambassador Auditorium were "deferred" until spring, while management scrambles to restructure the season, come up with a replacement for quake-damaged Royce Hall and work out credit arrangements with musicians and other creditors.

Staff and salaries have already been trimmed within the institution's $2.3-million budget, and creditors gathered on Friday to hear management's plea to hold off action. Orchestra members last week voted to accept a diminished concert and rehearsal schedule for the rest of the season, and their union on Monday was set to file a grievance for back wages and benefits.

"We faced an unprecedented convergence of economic and environmental issues," said board president Jennifer Diener. "The growth of audiences and gifts simply didn't keep pace with the orchestra's growth."

At stake is a high-quality, well-known musical group that has long been attracting subscribers and others to concerts at Ambassador Auditorium in Pasadena, the Japan America Theatre downtown and UCLA's Royce Hall on the Westside. Drawing heavily on Los Angeles' studio musician pool, the orchestra has made 26 recordings and toured both domestically and internationally.

"When I hear about this, my heart sinks," said Deborah Rutter Card, the chamber orchestra's executive director until fall, 1992, when she left for the same post at the Seattle Symphony. "I hear orchestras across the country, and I know the Los Angeles Chamber Orchestra is among the very best. I am very distraught by the idea that the chamber orchestra would not exist."

Formed in 1969, L.A. Chamber Orchestra usually presents 15 to 40 musicians, depending on what they're playing, and performs world premieres of new work as well as more traditional Mozart and Beethoven concertos and symphonies.

Like so many arts and other organizations, the orchestra grew and prospered through the '80s, adding subscribers, halls and patrons. In 1991, the board hired German conductor Christof Perick as its fourth music director, following prior leaders Neville Marriner, Gerard Schwarz and Iona Brown.