Oct 8, 2014 · 3 minutes

For Alex Selig, great sound quality is more than just an audiophile fetish. The cofounder and CEO of SoundFocus was born with hearing loss that requires him to wear in-ear hearing aids. Headphones and speakers that are personalized to the listener may sound like a first-world luxury, but Selig understood at an early age that not everybody's ears hear music the same way.

"I was seeking solutions to take a radically different approach to how we customize sound to the individual."

Today, SoundFocus has announced the culmination of Selig's personal and professional life's work: Amp is a soundsystem that slides onto your iPhone, acting as either a speaker or a headphone enhancement. The device's secret sauce is a software component that tests each listener's hearing at various frequencies to create a personalized sound profile for the user. Prior to launching Amp, Selig and his cofounder Varun Srinivasan say they gave the test to 150,000 people to collect as much as data as they could about how different people hear sound.

From the days of car CD players to Spotify's newly launched Equalizer, listeners have long been given ways to adjust the bass, treble, and other frequencies on the fly. But with the exception of the most dedicated audiophiles, do any of us really know what we're doing? And even then, each song, depending on its genre, requires different tweaks -- The bass you boosted on that Notorious B.I.G. track isn't going to do the Beatles any favors.

By automatically tailoring these levels to not only each user but also each genre, Amp takes the legwork and uncertainty out of sound optimization and personalization. But what about environment? The best-sounding levels when riding the subway are not the best-sounding levels when working at your desk. So SoundFocus also built a noise cancellation feature that is astoundingly good. Even while wearing the earpods that come standard with new iPhones, the difference I heard when turning this feature on and off was huge.

Selig and Srinivasan see their product as part of the natural progression of sound technology.

"In the 70s, you had great home audio quality, but it was not portable," Selig says. Then with the launch of the Walkman, the Discman, and eventually the iPod, things got portable but sound quality suffered. Next, Beats added a "fashion forward" element. "The next wave is going to be personalization."

The Amp hardware is fairly lightweight -- at around 100 grams, it's about half the weight of an Otterbox. It also contains its own battery, so Selig says it won't drain your iPhone battery. That said, as iPhones get larger and larger, culminating in the iPhone 6 Plus, will users want the extra baggage attached to their phone?

Maybe not. But in any case, for how reasonably unobtrusive Amp is, the sound quality is impressive. I can tell, having switched back and forth between a normal iPhone and an iPhone with Amp attached. Even better, it wasn't as if the founders had optimized the settings before I arrived to create an especially good experience. I set up my own settings through the listening test.

The device goes on pre-sale today for $69 and will ship in the Spring. At that time, the device will cost $129.

SoundFocus, a Y-Combinator alum, has raised $1.7 million in seed funding. As the founders of a hardware startup that already have a shippable product, Selig and Srinivasan have some valuable advice for people who choose to tackle one of the hardest, most expensive sectors in tech.

You want to make sure your testers won't just use it once and toss it aside -- that they'll value it and will be sure to offer feedback immediately if something goes wrong. For that, there's a simple solution, Selig says.

"For your first hardware beta, sell it. Don't give it away."

[image via SoundFocus]