The pressures of television scoring — limited budgets, frenetic time frames and perpetually uncertain future schedules — can frequently lead composers into some odd recording situations. Still, composer Robert Duncan deserves special recognition for the location he chose for his earliest scoring sessions for ABC’s freshman drama “Last Resort”: the unventilated interior of a 2000-ton decommissioned Soviet submarine off the coast of San Diego.

In setting out to score the Shawn Ryan-created naval skein, Duncan trawled the antique vessel with an engineer in tow, playing the sub’s gears, knobs and torpedo bays with hammers, mallets, metal bolts and body parts — improvising rhythms and melodies on the fly. Some of these recordings will end up playing major roles in the series’ score, though viewers would be hard-pressed to recognize them: Back in the studio, Duncan will take this found sound and manipulate it to the point that it can sit unobtrusively alongside traditional instrumentation.

“I don’t want to do sound effects,” Duncan explained, “but there’s an interesting connection when the source of the sound is native to what we’re watching on the show.”

For those who would question the logic of seeking out primary-source sounds only to render them unrecognizable, it’s all part and parcel of the composer’s intriguingly free-associative writing style.

“As I write, I’m always exploring with sounds, notes, chords and rhythms, and seeing how I feel about them,” the composer said. “Something has to stick. A long time ago I was scoring a scene of a plane landing, and I noticed that industrial, metallic percussion sounds seemed to just stick better than taiko drums or tom-toms or timpanis. Because we were looking at a great machine, there was some sort of a connection where it felt right to hear that sonically. So (using indigenous sound) helps me get to a place where the material is going to stick faster.”

This idiosyncratic approach has served the composer well. Born and raised in Toronto, Duncan relocated to Los Angeles a decade ago to attend ASCAP’s Film Scoring Workshop and soon found himself with a 20-episode scoring gig for cult hit “Buffy the Vampire Slayer.” Since then, he’s logged shifts composing for the likes of “The Unit,” “Lie to Me,” “Terriers” and “Castle,” the last of which sees Duncan return for a fifth straight season this fall.

While scoring last spring’s series “Missing,” for which he collected his second Emmy nomination, Duncan happened upon a junkyard typewriter that ended up providing a key cue, offering a glimpse at his process.

“I thought it was really interesting when I played a rhythm with mallets on the keys and ribbon spool, it made an interesting rattling that still sounded like a typewriter,” he recalled. “But when I brought it into the computer and started mangling it, and pitching some things down, putting distortion on other things, it turned into this infernal, machine-like beast of a rhythm. If I tell you later that it came from a typewriter, you’d probably be able to hear it, but not before.”

Even when taking found sound out of the equation, Duncan’s scores are often born of counterintiuitive strategies and rarely hew to expected beats. “Castle,” for example, was composed with a longstanding ban on strings and “vintage instruments” such as Rhodes piano or Hammond organ despite its distinctly vintage romantic comedy feel. The militaristic “Last Resort,” on the other hand, pointedly eschews any overly obvious martial sounds, drums in particular.

Though Duncan has found a welcome home in TV scoring, he’s nonetheless upfront about its limitations. “I get a lot of satisfaction out of writing music that has a production value behind it,” he said. “If TV can afford me to write at the production level of music that I’d like to write, I’d be happy, but that’s more common in film. Every cue for ‘Last Resort’ is getting mixed in very much a feature film format — all in surround — getting the royal treatment. And that’s really what I want the most.”