Mark Torres’ production of “King Lear,” the last of three plays in this year’s Maine Shakespeare Festival on the Bangor waterfront, begins with breathtaking pageantry. To an ominously pounding drumbeat, the actors march onto the stage in a royal procession. The scene is filled with primal, pre-Christian ritual, as King Lear, his daughters and their attendants appear from the dark backdrop of the river and the encroaching night sky. As if from the center of the earth, they rise with their chins in that unmistakable posture of privilege, power and certainty.

It’s a ravishing beginning, marked by the deep colors of Ginger Phelps’ period costumes and the crisp artistic vision of Torres. It’s brimming with the promise of a dazzling and sophisticated production. We can feel doom lurking behind the Stonehenge-like petroglyphs that make up the set, and a near-mystical quality immediately pulls us in.

Right from the start, Ken Stack’s King Lear is a man to fear, revere and suspect. His daughters, Sara Valentine (Goneril), Jennifer McEwen (Regan) and Kate Kenney (Cordelia), are sibling rivals to the teeth. J. Fitz Harris, as Edmund the bastard son of Gloucester, is richly shifty-eyed and draws the audience into his private scheme. Harold Withee, as Kent, shows the subtle depth of his character’s thoughtfulness. And Ben Reigel’s Edgar, the legitimate son, is stalwart and intense.

With all this swirling in the opening few scenes of the play, we can clearly see there’s trouble ahead. Unfortunately, it’s more trouble than the audience bargained for. The production, which lasts more than three hours, switches energy about an hour into the first half and slows to a less engaging pace. An irregular miking system and overpowering sound effects compromise the clarity of the spoken word, and uneven acting skills further complicate the high demands of this play.

There are plenty of worthwhile scenes – nearly any of the ones that involve Harris, Valentine and Withee. And Stack permits tender insight into a shattered man who is lost and wallowing in the misguidedness of his life and the deterioration of his prideful rule.

But this is a show that peaks early and then gets away from the cast. As much as we admire Torres for an unswerving devotion to meatier Shakespeare, this year’s production tests the audience’s resolve to find a comfortable place between a beloved text and the desire to see this festival be the best it can be. Finally, it stands in the shadows of the pertness of “Twelfth Night” and “Servant of Two Masters,” the two other shows that make up this year’s festival offerings and go further in the way of being crowd pleasers.

The Maine Shakespeare Festival will present “King Lear,” in repertory with “Twelfth Night” and “Servant of Two Masters,” on selected days at 8 p.m. through Aug. 18. For schedule and ticket information, call 942-3333. A free discussion of “Servant of Two Masters” will take place 5:30-6 p.m. Aug. 5 on the waterfront, and of “Twelfth Night” 5:15-7 p.m. at the Bangor Public Library Lecture Hall.