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Podcasts are huge, and they've created a demand for new music. At Berklee College of Music in Boston, students are learning how to make a living making music they'll likely never get credit for. Aaron Schacter from WGBH radio brought us this report earlier this week.

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AARON SCHACTER, BYLINE: Chances are you've heard lots of stuff like this in the past few years.

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SARAH KOENIG: From "This American Life" and WBEZ Chicago, it's "Serial."

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NINA PORZUCKI: Nina Porzucki here, and this is "The World in Words."

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UNIDENTIFIED WOMAN: Hi, it's "Slumber Party With Alie & Georgia."

SCHACTER: Podcasts would sound pretty bland without music. It's evocative and sets a mood. But for the most part, the music is meant to be invisible. You will never sit down to listen to it or put it on in your car, and chances are you'll never know who composed it. But this kind of music is everywhere, and it's big business.

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SCHACTER: This, for example, may someday be the sound that seduces you into buying a new Hyundai. You can't see the pictures that go with it, but trust me here. Music and images are kind of sexy. Sexy or sad, dramatic or heartfelt, the students in Commercial Writing 450 at Berklee College of Music in Boston already know how to tweak your emotions for films, for commercials, for production libraries. That's where podcast music generally comes from. Going to Berklee is a big deal for a musician. Loads of famous Grammy winners have studied here, but no one I spoke with would admit to thinking about fame. They were too pragmatic for that.

ANDREA PEJROLO: Pop stars kind of come and go (laughter), but the people working for them usually stay. You know, they're always there because they're always needed.

SCHACTER: Andrea Pejrolo is a professor in the contemporary writing and production department. He says of course his students have the same dreams as musicians everywhere. They do want to be famous. But these days, he says, they don't have to be to make it.

PEJROLO: It used to be, you know, to make it in the music industry was like to be the pop star. Now, we are surrounded by different type of media, you know, it just became this global thing now that keeps expanding. It's everywhere.

SCHACTER: In addition to film scoring, there's web advertising, lots more TV with lots more commercials, podcasts and video games. And this means there are so many more outlets where you can showcase your music and make money. Podcast music is not a moneymaker, by the way. Folks in the biz think of it kind of like a calling card to attract paying customers.

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MERCEDES AVILES: When you make music for a production library, you can just, like, completely let go of it.

SCHACTER: Mercedes Aviles is a violinist majoring in commercial writing.

AVILES: And so, even if you don't like what you produce, as long as it works for that spot, you can still get a sense of pride from it, even though it's not for your own personal use.

SCHACTER: Come on, Mercedes, you want to be a pop star, right?

AVILES: (Laughter) Maybe.

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SCHACTER: Professor Kurt Biederwolf says not too long ago, someone like Aviles probably would have spent a lot of time waiting tables while struggling for stardom. Now, he says, if she nails the commercial writing thing, it's all music all the time.

KURT BIEDERWOLF: They could do this from their hotel room. They could do this on a bus between gigs or during breaks. And this fits into those gaps in their schedule.

SCHACTER: Berklee is one of the only colleges in the country teaching undergrads to make commercial music, and they are running out of studio space.

For NPR News, I'm Aaron Schacter in Boston. Transcript provided by NPR, Copyright NPR.