Trailers for big, glossy tentpole movies typically deliver a booming symphonic score or operatic choral sounds to convey an epic feeling, though the downside to such larger-than-life bombast is the ring of overfamiliarity. The teaser trailer for “Battle: Los Angeles,” on the other hand, broke with convention by using the sparse, eerie tune “The Sun’s Gone Dim and the Sky’s Turned Black” from techno musician Johann Johannsson that played over wordless human action. It’s among the nominees for a Golden Trailer award.

“There weren’t a lot of ways to slightly re-interpret ‘alien invasion’ movies so we went really against the grain, which can be a risk,” says Nick Temple, owner and producer at Wild Card, which made the trailer. “It helped that the visuals that we worked with were massive and striking.”

If the trailer for “Battle: Los Angeles” challenged the status quo, it did ride on one of several trends sweeping the music in movie trailers business: utilizing indie music. Johannsson might be an established artist in his native Iceland but his music is new to most American moviegoers.

“Keep in mind trailers are branding campaigns,” says Yoav Goren, president of production music library Immediate Music, which licensed tunes to “Harry Potter and the Deathly Hallows: Part 2” trailer. “The studios want a unique sound to brand their movie.”

Trailers for big films can have it both ways by incorporating out-of-the-ordinary tunes at the start or middle, then climaxing with rich symphonic music, Goren says.

Finding engaging but little-known indie music is an obsession for music supervisors like Michael Sherwood at trailer house Create Advertising. “When someone asks me to get an indie track, I listen to all the other tracks on the album and get other material from the same label,” says Sherwood, whose credits include the trailer for “Alice in Wonderland.” “People send us music, there are indie music blogs and online music trades and I talk to other music supervisors. There’s always a push-and-pull between going with what is safe or what will be discussed.”

Another trend is creative talent from the movies — producers and directors — taking a role in the trailer development process, because previews that were once confined to theater screens have become more critical with their mushrooming circulation online. A decade ago, the same talent would focus on one-sheet posters, since those would eventually hang in their office.

“Sometimes, a film’s producer has a great idea for a song but, after a long process, you find out that the artist doesn’t want the music used,” says Angel Mendoza, music supervisor at trailer house AV Squad, whose credits include “Captain America: The First Avenger.” “So then you’re back to square one. This happens all the time.”

Film trailers are small works of art running less than 2 1/2 minutes, but typically incorporate 25-70 musical elements, or cues. With so much music in the mix, it’s no surprise that problems crop up with cues falling through for an assortment of reasons.

“Sometimes, the issue is not cost,” says Nick Martin, music supervisor at Flyer Entertainment that made the trailer for “Paranormal Activity.” “The client may want to replace a piece of licensed music at the last minute. That’s when you end up spending the night in your office with a cup of coffee” reviewing options from production libraries that have ready-to-go music.

As the production music business has boomed, the quality of such libraries has improved dramatically.

Music executives say the alternative — custom music — is making a modest comeback due to the increasingly fast turnaround required and technology that makes sampling, approvals via online and editing faster. “It can be created in two weeks to three days,” says Tim Arnold, VP worldwide business development and marketing at production library outfit Non-Stop Music, which can assemble an 80-piece orchestra in Utah on short notice.

A sort of unsung hero in trailer music is “sound design,” a kind of hybrid audio often fashioned with synthesized instruments. With advances in computer-controlled mixing, these samples have become more prevalent.

“The sound design elements may be unappreciated by viewers but if you were to take out them out it would be very noticeable,” says Bobby Gumm, a supervisor at Trailer Park. “With comedy and horror movies, in particular, sound design helps punctuate the ‘scares’ and jokes.”

Hitting the mark | Trailer shops cue music | Sound gardens | Where trailers are the star attraction | Kicking off summer a year early | Golden Trailer kudos: short and sweet | Golden Trailer nominations | Overseas trailers more permissive | The hit list