Myth and Kin Family lore anchors two new productions.

If during The Price’s intermission you should find yourself wondering if that first act you just witnessed was written not by Arthur Miller but by his warmer, funnier, anti-matter-universe twin: Yeah, you’re not alone.

In playing 89-year-old furniture dealer Gregory Solomon, veteran actor Robert Prosky discovers a great reservoir of tender, world-weary humor in Miller’s 1968 play. That’s the disconnect: Although the Arthur Miller most theatergoers know best possesses a comic sensibility, it’s a largely satiric one. After all, satire is just Funny With Something to Prove, and the preternaturally political Miller never met a set of ribs he wouldn’t happily poke.

Not here, though. Prosky’s Solomon spends a downright languorous first act engaged in a series of wildly discursive negotiations with Victor (Robert’s son Andrew Prosky), a forlorn beat cop on the cusp of retirement. Under discussion: the proper price for a hoard of massive old furniture that belonged to Victor’s dead father. This genially wistful conversation is loaded with laugh lines, which Prosky père tosses off lightly, making sure we feel the shrewd intelligence behind Solomon’s bumbling, avuncular exterior. “If they would build old hotels, I might be able to find a place for [your furniture]. Unfortunately, they only build new hotels.” It’s Antiques Roadshow by way of Columbo, and it’s a lot of fun.

Which is a head-scratcher, because in our universe the name Arthur Miller is found in the vicinity of the phrase “a lot of fun” about as often as it crops up near the phrase “drag queen bingo.” But then, just as you’re ready to chalk the whole thing up to some kind of massive dramaturgical transporter malfunction—and trying to decide whether Dark-Mirror Arthur Miller has a goatee or not—the second act starts. Within minutes, we find ourselves back in more familiar, stark-exploration-of-the-human-condition territory.

We arrive there on the heels of Walter (John Prosky, another scion of Robert), Victor’s long-estranged brother. Walter is now a successful surgeon, a turn of events largely attributable to the fact that he abandoned his family three decades before, leaving Victor to care for their ailing father. Suspicions and resentments arise, bitter recriminations between Prosky fils ensue. In other words: It’s Miller time.

When we meet them, both brothers are trapped deep inside the rationalizations they’ve carefully constructed and maintained for almost 30 years. Director Michael Carleton slams the hard edges of their self-deceptions against each other for most of the second act, allowing us to catch glimpses of the truths that neither son is capable of seeing. We watch Victor’s distrust of Walter rise up until he nearly chokes on it (Andrew Prosky spends a whole lot of his time onstage with his hands thrust into his pockets, regarding his brother with the same open-mouthed you-gotta-be-kidding-me face; you’ll likely wish the actor would switch things up a bit). And it doesn’t take long for John Prosky to turn Walter’s initial crinkly, affable smile of greeting into a feral snarl.

While all this is going on, Robert Prosky’s Solomon gets shunted offstage, returning only intermittently to throw out a pithy observation or two. You’ll miss him, but you might find other things to occupy you: Leisa Mathers plays Victor’s wife Esther as a woman just coming to the realization that sticking by the husband she loves means getting stuck herself. And you can almost smell the mustiness of Robert Kramer’s ingeniously cramped set, down to the real-looking cobwebs that glint in Jason Arnold’s sepia-toned lighting.

Does the much-hyped Prosky & Sons casting add any meta-fraternal/fatherly frisson to the proceedings? I didn’t pick up on any to speak of, but you might; mileage varies, with that kind of thing. It’s certainly hard to take your eyes of the elder Prosky as he turns in a performance that seems, more than anything else, effortless. But then, why would you want to?

Blaize Scully (Rusty Clauss), wizened Irish crone, harbors what might charitably be called a low opinion of her daughter-in-law. Here’s the old gal explaining in her braying brogue why the death of her mentally ill grandchild had its roots in her son’s poor choice of a wife: “Because when you breed animal with human, you can only get poor, haunted monsters!”

That’s about the level of subtle nuance and understatement awaiting you in Solas Nua’s disappointingly one-note Irish melodrama, Portia Coughlan. The one note in question is loud and long and so lacking in variation it might as well be the wail of a banshee.

The design team gives it a good crack: You won’t know what to make of Marie-Audrey Desy’s hanging strips of plastic when the house lights are up, but once the actors take their positions behind each one and Paul Frydrychowski aims his blue gels through them, and Chris Pifer floods your ears with the sound of rushing water, the effect is uncanny, even chilling.

And the cast is filled with solid actors doing their very best with what they’ve been given. Stephanie Roswell gives a quietly sympathetic performance as the heroine’s friend that somehow doesn’t get lost in the hurly-burly. Clauss is fun as the old coot, Grady Weatherford and Adam Segaller are memorable in small roles as the title character’s suitors, and Jonathon Church does good work as Portia’s long-suffering husband.

But there’s just too much that’s at once too over-the-top and too on-the-nose. Portia Coughlan is the kind of play that thinks it must name its characters after Greek, Shakespearean, and biblical figures to make sure you don’t miss its mythical themes. It’s the kind of play that uses music to underscore its heroine’s unhealthy obsession with her long-dead twin. The music cues in question? “I Am Stretched on Your Grave” and “You Were Always on My Mind.” It’s the kind of play in which the heroine doesn’t just miss her dead twin (named Gabriel, by the way). No, “The cows bellow for him from the barn on frosty winter nights!”

Playwright Marina Carr’s language is frequently lovely, but when it’s put in service of a tale this overwrought and capital-M Mythic, it just feels pushy and self-conscious. Carr is considerably more generous with the classical allusions than she is with her characters, especially Portia herself, who comes off here as merely shrill.

As Portia, Solas Nua Artistic Director Linda Murray feeds Carr’s penchant for excess. She expresses her character’s deteriorating mental state by stalking the stage with a scowl that Norma Desmond would think needed dialing back. And here’s something director Jessica Burgess should have caught: Murray plays her every scene with husband Church in much the same way: screaming at him while angling her torso forward and thrusting both arms behind her. This is likely meant to be balletic (Murray is a trained dancer), but it occurs so often and so identically that it ends up having a much different effect: It looks like the guy’s arguing with a ski-jumper.