It’s not unusual to see a composer conduct his own music in Hollywood. But it is startling to watch one lead an entire orchestra, and record the result himself without a scoring mixer — in the living room of his own house. Oh, and add to that the fact the show happens to be one of TV’s most acclaimed.

It’s a Monday morning in Agoura Hills, Calif., and “House of Cards” composer Jeff Beal is standing on a makeshift podium, addressing 26 string players. “A tiny bit shorter on the quarter notes,” he tells them. “This (scene is about) campaigning. It should be more fun!”

Wearing headphones, he conducts without a baton, guiding the violins, violas, cellos and basses with one eye on his score (moving bar by bar across a computer screen) and the other on a TV monitor displaying the latest cut of the episode itself.

Over the next two and a half hours, he will record an hour’s worth of music for the final two episodes of “House of Cards’ ” third season (debuting on Netflix on Feb. 27). Much of the music is dark and dramatic, befitting another climax in the saga of power-hungry Frank and Claire Underwood, now president and first lady of the U.S.

Beal has already recorded his own trumpet, piano and synthesizer; electric bass, played by his son Henry; and the operatic voice of his wife Joan. (“It’s the family band. We’re the Von Trapps,” Beal later quips.) He also has orchestrated the entire piece, and will mix it over the next two days in his home studio.

That rich string sound is the final element in his conception for the “House of Cards” finale. “Frank is president now,” Beal says, “so we’re dealing in a wider arena internationally. A lot of times I’ll have music like this, fully orchestrated and string-driven, and sometimes brutally simple music, like a solo piano. There are big contrasts.”

Beal, a four-time Emmy winner (and three-time nominee for his “House of Cards” music alone), operates like most composers in TV and independent film: on a “package” basis that requires him to write, record, mix and deliver all of the music for a single fee. He pays the musicians out of that money, but he likes the creative freedom and the streamlined production process that the terms afford. “It’s way less stressful for me,” he says. Beal notes that exec producer Beau Willimon wanted more rhythm in this season than in season two. But the producer says he trusts his composer to make most of the decisions about where the music goes and how strong or subtle it will be.

“We often whiplash from one emotional state to one that’s completely different in a single frame,” Willimon says. “Music helps us make those transitions, establish the pace, (and) uncover the emotional truths of our characters in ways that can amplify or add more facets.”

Willimon says Beal considers the big picture. “He’s not just tackling each scene as it comes, he’s looking at each episode as a totality. Then he’s doing that on a larger scale, thinking about a trajectory for music for the entire season.

“The best thing to do with a truly original voice is get out of the way and let it surprise you, listen to it and respond,” Willimon adds. “In Jeff Beal, you have a truly original voice.”