Inc.'s 11th annual 30 Under 30 list features the young founders taking on some of the world's biggest challenges. Here, meet Doppler Labs.

Noah Kraft wants to put a computer in your ear.

The 28-year-old co-founder of San Francisco-based Doppler Labs is introducing a new category of wearable technology--aptly called hearables--that optimizes sound through a pair of high-tech ear buds. The product's mobile app allows users to enhance live music experiences by turning the volume up or down on specific types of sound, or by drowning out everyday noise, whether it's in an office or train station or on an airplane.

"If you can curate someone's environment even by five decibels, that can be the difference between your ears ringing for three days or not," Kraft says.

Doppler's vision goes way beyond just creating a volume knob for the world, however. The mobile app has presets that let users manipulate audio in different ways, from equalizing sound levels at live events to adding effects like bass and reverb that make any listening experience sound like a concert hall. Want to mute the sound of a crying baby while still hearing everything else in your surroundings? Simply hit the "Baby" button on the app. "Everyone wants to hear the world differently, and we just want to give them the tools to be able to do that," Kraft says.

The idea for Doppler came to Kraft following a conversation with entrepreneur and investor Fritz Lanman. An angel investor in roughly 75 startups, including Square and Pinterest, Lanman previously founded recommendation app Livestar and spent nine years as a corporate strategy executive at Microsoft. In 2013, after hearing Kraft's idea for the world's first in-ear computing device, Lanman was ready to write a check and invest in the company. Kraft convinced him to join Doppler as a co-founder instead.

Last July, the company raised a Series B funding round led by media and entertainment investment firm the Chernin Group, bringing Doppler's total capital raised to $40 million. Other investors include Universal Music, Dreamworks co-founder David Geffen, talent agency William Morris Endeavor, and Henry Kravis, the co-founder of private equity firm Kohlberg Kravis Roberts.

Doppler's earbuds, called Here Active Listening, is what Kraft refers to as the company's "concept car." Doppler has sold about 10,000 units at a price of $200 each, primarily on the company's website. Nearly a third of those sales came through a Kickstarter campaign in 2015 that raised more than $635,000, but Kraft didn't turn to crowdfunding for the money. He and Fritz are building a community of early adopters to test out the product and report back on which use cases they found most valuable.

"I felt we should be doing headphone functionality, language translation, letting you talk to Siri, and all this other stuff," Fritz says, "but Noah said we needed to start very niche and targeted [to offer] the most magical experience we can provide."

Before making the product available to some 70,000 paying customers currently on a waiting list, Kraft wants to have the best version of Here possible.

"The number one use case we're getting is the open office," he says, adding that sounds related to commuting and everyday city noise are the second and third most popular use cases, respectively. "This is a time for investigation, experimentation, and learning." Doppler also recently partnered with music festival Coachella by offering a pair of earbuds to every attendee for $199. Kraft's goal is to introduce a mass-market version of Here by the end of 2016, and plans to charge between $200 and $300 per pair.

One of Kraft's earliest mentors is Rhode Island-based film producer Chad Verdi, who hired Kraft as an intern during his senior year at Brown University and quickly promoted him to the role of executive producer, running a 100-person film crew when he was just 21 years old. On their first film together, Verdi says Kraft was the hardest-working person on set, with the vision of a natural-born entrepreneur, always thinking further into the future than everyone else around him. When legendary film director Martin Scorsese expressed interest in executive producing Verdi and Kraft's biopic about world champion boxer Vinny Pazienza, called Bleed for This, Verdi was out of town, but sent the then 22-year-old Kraft to Scorsese's house to take the meeting.

"I had so much confidence in him meeting one of the greatest filmmakers of all time that I didn't blink an eye," Verdi says. After meeting with Kraft, Scorsese came on board as an executive producer.

At Doppler, Kraft has attracted talent that includes vice president of product Kennard Nielsen, former senior director of product for the Nike FuelBand and SportWatch GPS, and who previously led the product design team working on Amazon's Kindle Fire tablets. Kraft also hired sound expert Gints Klimanis, a former audio software specialist at Nest Labs and Apple.

While convincing people to wear a pair of high-end earbuds for hours at a time could sound like a tough sell, Kraft has extreme confidence in Doppler's ability to make waves in the wearable tech market.

"There are 14 billion ears in the world, and they're all on 24 hours a day," he says.