There’s some precedent for a married couple comprising a good indie rock band: You’ve got Low, for one thing, and The Weepies, and there’s Ian MacKaye and Amy Farina’s duo The Evens. By the same token, there have been some decent acts involving a parent and their child: Jeff Tweedy took dad-rock to the next level when he and son Spencer teamed up as Tweedy.

But when you venture into forming a band that includes mom, dad and son—well, you’re treading on thin ice. The phrase “family band” often conjures something hokey, like the Partridge Family setting out on the road in their multicolored school bus.

Essential Machine, it’s safe to say, doesn’t fit the profile of your standard family band.

The indie three-piece, which calls the Pittsburgh suburb of Greensburg home, has always been the vehicle of married couple Karen and R.J. Dietrich; they put out their first record under the moniker in 2009. But a funny thing happened in 2014, after the duo had already been recording and playing together for years: They incorporated son Robert into their act, on keyboards.

It’s worth noting, when we discuss Essential Machine as a family band, that it wasn’t created by a musical mom for didactic purposes, or crafted by a stage dad looking to establish a pop-music phenomenon. It was established by Karen and R.J., for Karen and R.J., and happened to grow organically to include their son. The core of the band still revolves around lyrics that both bring and melodies the two craft. Karen is a published author of poetry and a memoir, and her first novel is forthcoming from Grand Central Publishing in February 2020. (Now, as a three-piece, the band's writing process is more diffuse, but the primary duties remain largely the same.)

Essential Machine’s latest effort, Poison Control, due out in January 2018, marks a milestone in some ways for the band: The EP is its first record created with a recording engineer outside of the Dietrichs’ studio. Recorded with J. Vega at Pittsburgh’s Wilderness Recording Studio (the standard-bearer for indie-rock recordings in the city in recent years), it’s Essential Machine’s fifth EP overall.

Lyrically, Poison Control provides cinematic snapshots and fragments of feelings; repetition, vivid imagery and unexpected metaphor set up shop as one might expect from a band whose drummer is a poet. Musically, many of the songs come with the driving urgency and riff-happy guitar work of a band like The War on Drugs. Traces of Essential Machine’s folky-duo origins surface on the new EP, but more often we get glimpses of Essential Machine as an epic rock outfit—album closer “Burn Burn Burn” might be the triumphant closing number of a movie that doesn’t exist yet.

When you listen to Poison Control, you’ll likely get lost in the world the band builds with music; one thing you probably won’t be worried about is whether the band shares a last name. It’s one thing to be a family band, with all the trappings that might entail (the matching outfits, the bonding on the road, the Partridge Family bus, if that’s what you want). Essential Machine, though, could be considered something else: a band that also happens to be made up of a nuclear family.