Anyone who doubts the role of the audience in program-making had only to hear the Philadelphia Singers singing Loeffler, Martino, and Bruckner Thursday at Verizon Hall. The program, with its piquant instrumental aspects and unconventional content, was aimed straight at the ears of the Chorus America delegates holding their convention in Philadelphia.

The hall itself was aiming something at listeners' ears, too, for reflecting panels had been installed along the sides of the balcony level - a first step in trials aimed at adding presence and vitality to what has been a distressingly distant acoustical ambience.

Conductor David Hayes' program included an a cappella work; one for women's voices, organ and four instruments; and the Bruckner Mass in E minor, for big chorus and an orchestra of four horns, three trombones, and pairs of trumpets, oboes, clarinets and bassoons. It touched two centuries, dusted off Charles Martin Loeffler's period piece By the Rivers of Babylon, challenged singers and audience with Donald Martino's witty and pungent Seven Pious Pieces, and celebrated Bruckner's view of the future with its vast dynamic range.

The chorus seemed to gain from the acoustical adjustments. Hayes has made clarity a first cause, but in this setting, diction, intervals, and sectional balances seemed unusually pointed. Without that clarity, Martino's work would be mush. The singers move pitch to pitch, not chord to chord, and the placement of single notes in context with other single notes provides the spring in the music's step. This performance gave special spice to the oddities of the Robert Herrick poems. Does his piety meet standards of orthodoxy? No more than Martino's music bows to conventional practice. This was the evening's high point.

Hayes shaped the Bruckner Mass in a soaring arc. From the opening trombone chorale through the highly personal emphases Bruckner applied to the text, the music grew, to climactic moments in the Gloria and the expansive Credo and to the introverted final notes. He summed up the level of this performance in the Sanctus, the singers hushed, noble, joyous and wonderfully resonant. He let the instruments color the whole, but also take firm stands of their own.

The Loeffler piece, for 18 women, two flutes, cello, harp, and organ, showed the acoustical problems still in the hall. Loeffler's subtle instrumental colors were lost any time the organ sounded, but at the same time the voices seemed clear at all dynamic levels. The work, performed fluently, deserved better.