Something strange seems to be happening in that spiffy new concert hall in Orange County. People are clapping.

The happy and justifiably proud Costa Mesans, and friends, are clapping con brio and con gusto. They are clapping loudly, smugly and dutifully. Unfortunately, they often are clapping in the wrong places, and possibly for the wrong reasons.

This has made the presumed recipients of the applause palpably unhappy. Even more irksome, apparently, it has made critical observers unhappy.

The journalistic unhappiness has, in turn, made the clap-happy ones unhappy. The cycle is complete, if not vicious. Also profoundly bemusing and mildly vexing.

At the supergala brouhaha extravaganza that marked the grand opening of Segerstrom Hall, one of the fund-raising cheer-leading we're-all-right-Jack speech-makers instructed the assembled devout--who had paid up to $2,000 per ducat--to applaud themselves.

The glittery throng, 3,000 strong, didn't need to be asked twice. Nor did the masses stop clapping when the obligatory throat-clearing and back-patting exercises ended.

Zubin Mehta was on the podium for the mighty, eloquent, ultimately jubilant Ninth Symphony of Beethoven. One may or may not admire his interpretation, but one must respect his sense of architecture.

He clearly thinks of the work as a unified statement, as a continuous expressive crescendo that begins with the first ominous note of the first movement and reaches a climax only with the final thunderbolts of the "Ode to Joy." The silly old composer, long dead, harbored similar convictions.

The eager first-nighters, however, showered the stage--and, perhaps, themselves--with ovations whenever they sensed an imminent pause or cadence.

Forget about cumulative tensions. Forget about letting any emotional impact sink in. Forget about Beethoven's probing agonies and noble ecstasies. Never mind interrupted thoughts and short-circuited communication on both sides of the proscenium.

Mood-shattering, push-button cheers and instant hoorays seemed mandatory at every turn. No, between every turn.

Mehta raised his arms in obvious disapproval if not disdain. He glared and glowered as only he can glare and glower. He looked like a policeman at an intersection staring down four rows of souped-up Rolls-Royces manned by impatient teen-agers.

The conspicuous consumers paid no heed. What does the conductor know? Who cares what he wants?

A few nights later, Leontyne Price joined Kurt Sanderling and the Los Angeles Philharmonic for the tender, aching, valedictory sentiments of Richard Strauss' Four Last Songs. A cautionary note in the program requested applause only after the final song. Unmoved, the audience all but ruined that performance, too, with premature ovations.

The soprano, still as a statue, ignored the well-meant interruptions. The conductor motioned for silence. It was all in vain.

A few nights after that, Price returned for an evening of songs and arias. The crowd buried her in salvos of admiration throughout the program. Ironically, the celebrants could muster only enough applause to bring the diva back for two encores. She normally gives more than that. Ovations apparently come easy in Orange County, and go even easier.

The following week, Isaac Stern took the stage for a recital. The zealous noise makers in attendance started congratulating him, and, perhaps, themselves, in mid-sonata.

He raised his bow in protest. The music-lovers paid no attention. When the sonata was over, an unusually strong measure was taken: A voice on the public-address system begged the audience to withhold its applause. So much for public education.

Christoph von Dohnanyi recently led the vaunted Cleveland Orchestra through Tchaikovsky's "Pathetique" in Orange County. He, too, tried desperately to quell inappropriate applause. John Henken reported the visiting maestro's distress on these pages: