Composer Mark Snow is in his tiny West Los Angeles studio putting the finishing touches on his score for the 100th episode of “Ghost Whisperer.”

Seated at his trusty Synclavier — the synthesizer-sampler that was his musicmaking partner through 202 episodes of “The X-Files” — the veteran composer plays the keyboard, adjusts output levels and fine-tunes the musical sounds that will propel the action, underscore the dialogue and supply much of the emotional core of the show.

“What’s fun is that you can do melodic music, sound-design music, tension music, really the full gamut,” Snow says. “It ranges from warm and human moments to World War III gangbusters.” He has scored all 100 episodes, including composing the main theme (and a separate theme, “Gordon’s Dream,” for the end credits).

Two of Snow’s 15 Emmy nominations are for “Ghost Whisperer” scores, and three more are for telepics and miniseries directed by the show’s creator, John Gray (including “Helter Skelter” and “The Day Lincoln Was Shot”), with whom Snow has been working on various projects since 1990.

“The challenge with this series,” says Gray, “is that it’s part horror show and part emotional drama. Mark has chops in both of those genres. He’s really brilliant at creating that kind of atmosphere and character depth, the whole world of fear and Gothic horror we do on the show.”

The artistic main-title imagery posed a special scoring challenge.

“This is a show about grief, closure and coming to terms with death,” notes Gray. “There had to be elements of mystery, emotion, horror — the sense there are things out there that scare us, that we don’t understand. I talk to Mark as I would talk to an actor about what I’m looking for, and he responds in the same way.”

Snow writes 30-35 minutes of music per episode, usually over an average of five or six days. The Juilliard-trained ex-oboist started his career 35 years ago writing orchestral music for shows such as “The Rookies,” “Hart to Hart” and “T.J. Hooker.”

But he has long been a realist about the fact that most series budgets no longer allow for real musicians, and that time frames have collapsed for composers, who must now generate twice as much music in half the time they once were allotted. The improvements in music-related technology over the past two decades, Snow says, “allow you to be much more musical than when this all started.”