She ponders: What would Portia do?

“What is it about men and cars?” muses Kate, the troubled songwriter heroine of “Lady Macbeth Sings the Blues,” in the wake of her husband’s phone call brimming with coded agendas. “After all these years I know when he says, ‘check your oil’ he means ‘I love you.’ But still, it doesn’t quite have the ring of ‘Shall I compare thee to a summer’s day....’ ”

The ironic clash between the poetic language of Shakespeare and mundane modern life figures prominently in singer-lyricist Amanda McBroom and composer Joel Silberman’s smart, touching new solo-performer musical at Ventura’s Rubicon Theatre.

McBroom’s formidable voice could wring pangs of heartache from a shopping list, but the show’s unusually thoughtful premise offers plenty of depth as Kate, caught in a midlife crisis, seeks inspiration and guidance from the various women of Shakespeare’s plays. Her meditation on her husband’s automotive substitutes for a romantic vocabulary sets up the witty title number, a blues lament, delivered in impeccable Scottish brogue, in which the tyrant’s wife consults “Dear Abby” about her marital difficulties. (“I really love the lug / And do you know the trick / To getting stains out of a rug?”)

A rocky marriage is only one of the pressures facing Kate as she sits in a Cleveland hotel room trying to pen the lyrics for a musical version of “The Merchant of Venice” -- a task she’s reluctantly inherited due to the sudden death of her ex-writing partner, from whom she parted on bitter terms.

In a series of songs spanning an engaging mix of musical styles, McBroom’s Kate considers the various stages of her life from the vantage point of her literary idols. A pair of sweetly lyrical ballads explore Juliet’s naive adolescence and Ophelia’s awakening to strange new emotions. Kate’s namesake from “Taming of the Shrew” croons her refusal to compromise until she finds “A Man With a Mind,” while Goneril, King Lear’s evil daughter, belts out her repressed menopausal rage in a rowdy rock tune.

In contrast to Kate’s compulsive pleaser personality, Cleopatra presents an attractive if unattainable alternative in “It’s Nice to Be a Queen,” a sultry tango.

The biggest issue facing Kate, however, is her awkward attraction to a younger man, which she confronts in a trio of pop numbers voicing Olivia’s unexpected discovery of love (in “Twelfth Night”) and the dangerous allure of inappropriately placed passions (“Hamlet’s” Gertrude and Lady Ann from “Richard III”). Having to choose between her husband and a fresh start drives Kate close to a breakdown, until she finds relief from relentless self-criticism in the words of Portia, the very character she’s trying to write lyrics for.

The quality of mercy may not be strained, but the climactic tie-in to Portia unfortunately is -- the show needs more work to draw its pivotal insight from more than a single line of text, especially when earlier themes are connected more fully to characters.

Otherwise, the Shakespearean conceit is skillfully realized and delivered amid Larry Hochman’s remarkably full synthesized orchestration, and Trefoni Michael Rizzi’s scenic projection and lighting design. Mitigating the single-actor format, a succession of phone messages from various characters placing demands on Kate feature the voices of George Ball, Tovah Feldshuh, Charles Randolph Wright, Kevin Earley, Jay Rogers and Jim Dale.

Lady Macbeth may have the blues, but McBroom and Silberman should be singing a different tune at the auspicious debut of their charming new musical.

*

‘Lady Macbeth Sings the Blues’

Where: Rubicon Theatre, 1006 E. Main St., Ventura

When: 7 p.m. Wednesdays, 8 p.m. Thursdays and Fridays, 2 and 8 p.m. Saturdays, 2 p.m. Sundays

Ends: July 11

Price: $25-$45

Contact: (805) 667-2900

Running time: 1 hour, 40 minutes