There were many empty seats at the Music Center at the start of Thursday night’s Los Angeles Philharmonic concert, and many more after intermission. The sounds of electronic beepers and the squeal of moribund hearing aids rang out in the vast spaces. Even after 250 years, the three-hour-plus bulk of Bach’s “St. Matthew Passion” is an intimidating presence. In all frankness, the work is a strange presence as a subscription event at a series mostly dedicated to noisy romantic symphonies. (It was even more out of place at the Hollywood Bowl in the summer of 1985, when the haunting moment describing the death of Jesus was punctuated by a car alarm.) Yet the nature of the work, its hold on the emotions of any listener willing to give in to its splendors, demands some kind of hearing in some kind of context. Peter Schreier, who conducted this week’s performances (repeated tonight at the Orange County Performing Arts Center and Sunday afternoon at the Music Center) has dreamed up his own manner of presentation, and for the most part it worked; when it didn’t, on Thursday night, the fault was not his. Schreier is, of course, better known as singer than conductor; he can only conduct, he said recently, music that he also sings. The idea of combining the role of Bach’s Evangelist with conducting makes a great deal of sense, furthermore, since his is the central role in the work, and his own vocal lines tend to activate most of the music’s other elements. To make this work, Schreier has fashioned his view of the Evangelist’s music around a highly emotional delivery. He breaks through the mask of stylized Baroque singing. He erupts in anger and scorn at the lies and corruptions of those who have sent Jesus to the Cross; he melts in agony as he tells of Peter’s threefold betrayal. His Jesus was the marvelous young bass Olaf Baer, known chiefly for his splendid artsong recordings. The heartbreaking vulnerability of Baer’s delivery became the perfect balance to the intensity of Schreier’s conception. If only the other soloists had been up to this level! Memories of bygone Elisabeth Schumann, Janet Baker or Kathleen Ferrier recordings reflected no glory on the thin, pinched singing of soprano Ulrika Sonntag and contralto Elisabeth von Magnus. It was even more depressing to experience the watery singing of the tenor and bass arias by David Gordon and David Evitts, standing next to the singers — Schreier and Baer — who could have sent this music heavenward. It was, then, a only a fair representation of a work deserving far better. The Philharmonic’s forces performed well, as did a small contingent from the Master Chorale. The Paulist Boy Choristers, who sang the chorale that floats across the top of the amazing opening chorus, could barely be heard — the fault, most likely, of the curious stage arrangement to allow Schreier some eyeball contact with singers and orchestra, while singing toward the front. Oh well, it was a noble idea that almost worked. Sibelius next week; back, alas, to normalcy.