O.C. MUSIC REVIEW : Approach to Mozart Quiet but Daring : Pacific Symphony, led by guest conductor George Cleve, presents a no-frills program exploring the byways of the composer’s art.

No trumpets blared, no cymbals crashed, no bombs burst in mid-air. Leave those for the barbarian hordes at Hollywood Bowl.

At Irvine Meadows Amphitheatre on Saturday night, the Pacific Symphony tried a subtler approach to the summer outdoor concert. In its own quiet way--in fact, because of its quiet way--it was daring.

Guest conductor George Cleve, founder of San Francisco’s Midsummer Mozart Festival, had put together a no-thrills Mozart program for this occasion, a program that explored some of the byways of the composer’s art.

The “Posthorn” Serenade, K. 320--so called for its use of the post horn, an instrument which announced the arrival of mail--served as the backbone. Inserted within it, in the practice of Mozart’s time when pieces where broken up in this way, was the mellow and melodious Piano Concerto in A, K. 488. The Two Marches, K. 320a, thought to be bookends to the “Posthorn,” became the prelude and postlude to the concert.

The 26-year-old Korean-American pianist Seung-Un Ha was the unassuming and impressive soloist in the concerto. Clarity of articulation (but never pearliness) and pint-sized nuance (but never preciousness) defined her interpretation, as did a subtle accent and inflection of rhythm, which kept it pointed and vibrant.

Her approach was straightforward and understated--appropriately so, since this piece’s charms aren’t hard to find--yet always firm and eventful because she managed to project intimacy of feeling, not keep it to herself.

The sole drawback was the microphoning, which rendered the sound of the Yamaha grand at once boxy and bright. Cleve and the Pacific Symphony offered a detailed and delicate accompaniment.

Detail also invigorated Cleve’s reading of the “Posthorn,” as he seemed to uncover all of the intricacies behind its simple, tuneful facade. In addition, he coaxed music--gracious, shapely music--from the entire ensemble, from second bassoon to post horn, and enforced an exceptionally broad dynamic range.

He let the orchestra phrase with consistent finesse and elegance, though always refusing to make too fine a point. He could get things going at a good clip, but nothing was ever pressed, rushed, harried.

The Pacific ensemble responded alertly and expressively, the occasional frayed edge notwithstanding. As the 7,146 in attendance (or most of them) applauded heartily, Cleve held up the score, giving credit where credit was due.