On the face of it, an abstract mounting of “Company” makes perfect sense. With the possible exception of “Pacific Overtures,” “Company” is the most presentational of all of Stephen Sondheim’s musicals. All but a few of the deceptively bouncy songs in his 1970 examination of romantic ambivalence are delivered with a sort of faux-Brechtian overlay, as singers overlap, interrupt, or otherwise comment upon George Furth’s acidic dialogue.

Enter director John Doyle, whose pared-down reinvention of Mr. Sondheim’s “Sweeney Todd” earned him strong reviews and a Tony Award last season. Mr. Doyle’s “Company,” sounder in conception but muddier in execution than his previous outing, follows the same basic template — the 14-member cast accompanies itself on musical instruments, eliminating the need for a conventional pit orchestra.

But despite the occasional bit of staging trickery and Raúl Esparza’s magnetic performance as Bobby, the charming but slippery commitment-phobe at the play’s center, a conceit that leapt off the stage in “Sweeney” now feels hogtied by its own logistical requirements. Owing in part to an overall dip in quality among the performers in their traditional, as well as in their new responsibilities, Mr. Doyle’s polarizing style feels less like a refreshing (if sometimes confusing) rethinking this time around and more like a cost-cutting novelty.

The five married couples who make up Bobby’s close circle of friends in “Company” have gathered to commemorate their bachelor pal’s 35th birthday with a (possibly imagined) surprise party. This assemblage gives way to a mosaic of unsparing glimpses at modern marriage: The couples take turns envying, condescending to, mothering, pitying, and lusting after Bobby, all the while giving voice to the pitfalls and pleasures that make spouses, to use Mr. Sondheim’s indelible phrase, “Sorry/Grateful.” Or, as the jaded, frequently soused, Joanne (Barbara Walsh) sings, it’s

The concerts you enjoy together,
Neighbors you annoy together,
Children you destroy together,
That keep marriage intact.

By eliminating most of the score’s “buttons,” the emphatic musical cues that coax an audience to applaud at the end of songs, Mr. Doyle gives an added sense of seamlessness between Mr. Furth’s words and Mr. Sondheim’s music. This, however, has the undesirable consequence of calling added attention to the padded book scenes. (Several of these are adaptations of earlier Furth playlets, and they remain insufficiently integrated.) With much of David Gallo’s minimalist set devoted to Lucite cubes on which the musicians sit and to a central piano, there isn’t much room for Mr. Doyle to maneuver his performers around the stage; the result is a procession of couples filing past Bobby to little effect.

It doesn’t help that the overall level of both musical and acting ability is markedly lower this time. (Dance is essentially a nonfactor, as the sultry “Tick Tock” solo has been cut.) Mr. Furth’s brittle bons mots can be tough to put over, true, but much of the cast fails to imbue them with the wit or pathos they require. And even with Mary-Mitchell Campbell’s simplified orchestrations, not all of the lyrics are intelligible, a fate that the more complex “Sweeney” avoided.

There are certainly exceptions: Elizabeth Stanley and Kelly Jeanne Grant are convincing as two of Bobby’s three girlfriends, while Leenya Rideout and Fred Rose acquit themselves as Jenny and David, whose brief walk on the wild side comprises one of Mr. Furth’s more belabored sequences. (Ms. Rideout’s instrumental skills are also quite strong.) And Mr. Esparza, who almost never leaves the stage, offers a wholly plausible blend of charisma, aloofness, and crippling uncertainty to guide his splendid tenor through such masterful musical distillations of uncertainty as “Someone Is Waiting” and “Marry Me a Little” (a relatively recent addition to the score). Overall, though, the enforced versatility appears to have resulted in artistic compromises on the performance side of the equation.

A different sort of disconnect accompanies the casting of Ms. Walsh in the pivotal role of Joanne. Ms. Walsh sings with a plusher alto and cuts a considerably more glamorous figure than most Joannes (Debra Monk and Lynn Redgrave in recent major revivals, to say nothing of the inimitable Elaine Stritch), which has a curious effect on the play. The sexual tension is markedly higher in a crucial Act II confrontation between Joanne and Bobby, but she also seems less scarred by the vicissitudes of much-married life. Although Ms. Walsh is older than Ms. Stritch was when she created the role in 1970, her rendition of “The Ladies Who Lunch” serves less as a dismayed view of her idle-rich surroundings and more as a premonition of things to come.

Ms. Campbell cannily builds her “Ladies” orchestration up from a simple, cabaret-style piano arrangement. But despite having more musicians at her disposal, she delivers a thinner, less enveloping sound than Sarah Travis did for “Sweeney.” Granted, the pop-inflected “Company” score can withstand a dip in lushness that the more operatic “Sweeney” cannot. But the absence of Jonathan Tunick, the ingenious original orchestrator on both Sondheim shows, is felt more acutely here, as several songs have an underpopulated feel.

It doesn’t help that the more clever incorporations of the musical instruments are given to toss-away jokes, as when Joanne plinks her cocktail glass instead of a triangle or when the three girlfriends use saxophones to “sing” their boogie-woogie arpeggios in the 1940s pastiche number “You Could Drive a Person Crazy.” Both are perfectly good gags, but add little to the audience’s understanding of the way music helps these 14 individuals navigate their way through the bruising harmonies of modern-day city life.

There is one exception to this quippy approach: Bobby. Until the final scene, his instrumental responsibilities are confined to one very brief turn on the kazoo while everyone else makes beautiful (or discordant or regretful) music together. It is Mr. Doyle’s thesis that Bobby literally finds his voice when he shelves his ambivalence and takes a tentative step toward the prospect of “Being Alive,” Mr. Sondheim’s crushing if slightly unearned finale.

After a piercing scream against the misgivings and hesitations that have thus far defined Bobby’s life, Mr. Esparza sits down at the piano and begins playing “Being Alive” with a violent insistence that gradually calms down into a harmonious accompaniment. It is by far Mr. Doyle’s finest moment in “Company,” and a welcome reminder that the actor-musician notion is more than just a gimmick. Unfortunately, the very existence of such a reminder shows that Mr. Doyle has failed to make the case sufficiently this time out. It’s possible to be grateful for his inventive efforts and sorry at the result.

Open run (243 W. 47th St., between Broadway and Eighth Avenue, 212-239-6200).