On “Lonely Telephone,” an EP released by Greensburg band Essential Machine about a decade ago, acoustic-based tunes bubble and float, underpinned by quirky xylophone pings and an indie-folk-music aesthetic.

As the band — husband and wife R.J. and Karen Dietrich, and their son, 20-year-old Robert — prepares to release its second full-length record, “Exponential Crisis,” that sound has been shot through with much more of a sharp, electric edge. Warbly synthesizers cut through the coda of “Almost Outta Here,” as R.J. Dietrich sings, “We almost made it.”

“New instruments really drove a lot of the writing for me,” R.J. said. “When we started, we’d just moved from Florida, and I’d gotten rid of every instrument I had except for an acoustic guitar. Then I got a mandolin, and if you listen to ‘Lonely Telephone,’ you can hear all this mandolin. Then I got a computer with some synthesizers and you can hear some of that creeping into the mix.”

What crept into the mix for the new record was the isolation of the covid-19 pandemic.

The album’s opening track is a remix of a down-pitched chorus from a later song, “In the Tub”: “You’re in the tub/Drinking all of the rum/Wishing you were the one/Wishing you were enough.”

“This record was written during the pandemic, and the trajectory we were on with the first record changed overnight,” R.J. said. “We were about to do a bunch of things, and then couldn’t. For us, we’ve spent so much of our lives doing this, and to have no idea of what’s going to happen — ‘In the Tub’ is kind of a response to that.”

Robert Dietrich then took the vocally-stacked chorus from the tune, dropped the pitch and created a haunting intro to the album.

Both his parents said that’s indicative of the growing role Robert has taken since joining the band in 2014.

On the album’s close, “Late Summer,” the band kept the song going in recording sessions with the idea of fading it out. But Robert began stacking synthesizers atop the repeated chorus — “Of all the thing that never were” — rebuilding the end of the song into a rising, frantic crescendo.

“He layered a ridiculous amount of synths on it,” R.J. said. “He built this amazing track. I went into the studio and ended up laying down the vocal track in one take. So when we were listening back to it, every time we’d talk about fading it out, but then we’d go, ‘Well, we really like it,’ so we decided we’d just be obnoxious and make an eight-minute song.”

Karen agreed.

“For me, that’s one that stands out,” she said. “I remember we wrote it during the shelter-in-place stuff that was going on (at the start of the pandemic). We were trying to convey that sense of feeling very lost, not getting out of the house, and when you do, you’re still kind of alone. We went on so many walks at the start of the pandemic, and there was almost nobody around. ‘Late Summer’ tries to capture that emotion.”

Robert said the increasing complexity of his keyboard setup has helped contribute to the wider sonic palette on the band’s last two records.

“I’ve built up a collection of more and more synthesizers, and as that grows, my ability to add new things to new songs also grows,” he said. “It leads to me creating more sound that ends up driving a lot of the songs we’ve been writing.”

“Exponential Crisis” will be released May 20 on Lemon Tree Records, and will be available in most streaming formats as well as a special cassette tape that the band will sell at its live shows.

For more, see EssentialMachine.net.

Patrick Varine is a Tribune-Review staff writer. You can contact Patrick at 724-850-2862, [email protected] or via Twitter .