There is a certain thematic logic to the fact that “The Day,” a cello-and-dance work about living and dying, is not all light. Quite the opposite: It is weighted toward somberness. Yet as a theatrical experience, a great deal of somberness and impenetrability can blot out the subtler qualities, no matter how lovely they are, and leave you feeling trapped.

So it was in this handsomely designed but overly dense piece, featuring cellist Maya Beiser and former ballerina Wendy Whelan. The two women shared the stage of the Kennedy Center’s Eisenhower Theater on Friday. The final 10 minutes of “The Day” were exquisite: Moonlight flooded the stage and you felt transported to a glorious hereafter, largely due to the delicacy and soft beauty of Whelan’s movements. She springs and skims so lightly that she seems to tread on air. Whelan, the former New York City Ballet star who is now that company’s associate artistic director, also has a remarkable ability to communicate compassion, simply through the noble quality she brings to the stage.

Yet the piece felt unbalanced. Leading up to its serene ending were passages of loud, high-pitched cello layered with dissonant recorded tracks; a larger-than-life, slow-motion video loop showing a cello smashing to the ground and busting open, accompanied by deafening sound effects; and an interminable, expressionless recording of Beiser and Whelan reading how dozens (maybe hundreds) of folks had filled in the statement “I remember the day . . . ”

This portion, which took up the first half of “The Day” (which was roughly 75 minutes long in total) contained such gems as: “I baited my hook,” “I came across it in a local yarn shop” and “I got the email.”

What was all this all about? In a program note, Beiser, who conceived of the production, writes that “The Day” comprises two pieces composed for her by David Lang. It takes its name from the first one, in which Lang crowdsourced text from the Internet to explore “the ways we remember our lives.” The second part, titled “World to Come,” was inspired by 9/11. Beiser describes it as a meditation on the “journey of the soul as it separates from the body.”

The concept is interesting, to be sure: One way to look at humanity is as the sum of individual experiences that have been forged into memory. Death, particularly a violent one, destroys the body that houses those memories. (Presumably that is what the smashed cello and the painfully loud music were meant to evoke.) And yet something ineffable and meaningful remains, an unquenchable spirit, still in motion, drifting upward toward heaven, or the open universe, or the stars.

Whelan is the perfect embodiment of this idea, with her qualities of lightness, ease and elegant simplicity. The choreography, by the respected veteran artist Lucinda Childs, who favors a minimalist approach, emphasized linear simplicity and sequences of clear, quick steps. At times, Whelan busily manipulated props — a long cape that mostly got in her way, an elastic loop, ropes — with differing amounts of visual interest but whose thematic function was not clear. Natasha Katz’s atmospheric lighting design edged the dancer in gold, and helped hold the whole production together.

Taken individually, many of the creative elements of this production were attractive. The problem was in how they were mixed together. I wish that Beiser, who is listed as creative producer of “The Day,” had more faith in Whelan and Childs and their ability to evoke poetry and emotion through simple movement and gesture. As it was, the layers of sound, projections and props muddied a provocative concept.