Entrepreneurs Remix the iPhone App The device's musical interface capabilities are creating a world of pocket producers.

Austrian Michael Breidenbruecker had the same idea in his head for nearly 10 years: Create a software application that provided a personal soundtrack to your mood, movement and speech. His app would be reactive, using pre-programmed electronic music that would change according to sensory input.

The problem for the 37-year-old was that available hardware wasn't up-to-speed. The traditional desktop, laptop or mobile phone didn't provide the sensory interface required. Then the iPhone came along.

"When I saw the iPhone, I knew this was the perfect device," says Breidenbruecker, who co-founded the music site Last.fm. "Its processors can do everything we need it to do. It has sensory input. And the thing that makes the iPhone really, really attractive for music apps is simply the fact it is a music device--people use it to listen to music."

Indeed, while many iPhone software startups focus on making a quick buck through simple games and novel gimmicks (iBeer turns the gadget into a virtual mug o' brew), many savvy programmers are focusing on the burgeoning world of iPhone music programs and have only scratched the touch screen of possibilities. The iPhone's tactile interface, motion-sensing accelerometer, wireless capabilities and built-in iPod music functions make it an ideal device for new legions of pocket producers and music fans alike.

Musicians ranging from Brian Eno to DJ Deadmau5 have created and endorsed iPhone music apps. Though it's not clear how many of the Apple iPhone App Store's 20,000-plus programs focus on music, it is true that, even in this recessed economy, this new mobile platform is making instant moguls of savvy developers. The technology, startup costs and workforces involved are not as daunting as they would be if you were launching full-service software.

"I think it's such a great business model that Apple has set up for us creators," says Jeff Muncy, creative director of Psyclops LLC, a Los Angeles-based app developer. "I don't want to say it was completely smooth, but it wasn't too hard. You just need to be creative and be unique. There are so many 'me-too' apps out there."

Breidenbruecker's RjDj app, perhaps more than any other, exploits the iPhone's musical capabilities. The $2.99 "album" version (there's also a free "single" variant that's rudimentary) lets iPhone users chose a musical "scene," which then mutates as you speak into a connected, microphone-equipped headset. The music can also react to your movement, as it reacts to the handset's bearing-sensing accelerometer. RjDj's often-ambient electronic sounds are calm in conditions of silence and stillness but grow more cacophonous as volume and action ensue. Users can record the program's reactions.

"We're pushing the boundaries of the hardware and the platform," Breidenbruecker says, "using sound input and output and real-time signal processing."

He says his company, Reality Jockey, consists mainly of himself, one programmer and five supporting employees, and that it has yet to make a profit. But at 150,000 downloads and counting, Breidenbruecker thinks the app is well on its way to becoming an artistic and commercial success.

And it could lead the way toward a new paradigm for music consumption, where fans download an ever-changing app rather than static songs, he says. Music stars could be programmers, not singers, rappers and rockers. In fact, RjDj is open to developers who want to create their own musical scenes to add to the album version. The only hurdle--one that Breidenbruecker hopes will be addressed by Apple--is that new music added to the program can't be sold and downloaded individually. Software music production suites such as Reason usually come with standard instruments built in, but if you want a specific hip-hop drum kit, for example, you have to purchase an add-on disc. Add-ons for iPhone apps, on the contrary, don't come packaged individually. For now, RjDj comes bundled with its music.

"What we want to be is a platform for artists to produce reactive music," Breidenbruecker says. "In order to do that right now we don't have many options with Apple because they don't support itemized downloads."

Still, developers are flocking to the App Store to peddle their music wares. Product developer Joy Kovaleski paired up with TV producer Muncy to get in on the action. Their product, Psyclops, launched this month and encourages children ages 8 to 14 to pair custom music tracks with animated dance moves of their choosing.

"What we saw as we looked at our market was [TV's] Randy Jackson Presents: America's Best Dance Crew and So You Think You Can Dance," Kovaleski says. "We felt our unique combination of music and dance that could be turned into a creative video was something that wasn't being done."

Gaming apps seem to be the biggest sellers at the App Store, so Psyclops is a wise blend of music and game-like aspects. And the resulting music videos can be e-mailed to friends in a whirlwind of viral marketing that benefits the makers of the $1.99 program. The company's founders hope to expand the app so that it includes a karaoke-like sing-along function, a personal photo feature and mass e-mail-blast capabilities.

Like other iPhone app entrepreneurs, Muncy and Kovaleski kicked things off with zero full-time employees and have so far contracted for services such as programming and marketing. Angel investors helped them get off the ground. "We hope to sell millions," Kovaleski says.

Of course, there's one more model when it comes to making an iPhone music app: Free. Eric Redlinger, researcher-in-residence at Brooklyn Polytechnic University's Integrated Digital Media Institute, used the school's resources to develop Mrmr, an app that allows electronic musicians to control digital gear wirelessly with their iPhones. It can be used, for example to control a DJ's set via Ableton Live software, or it can even be the remote control for a live VJ. It also allows collaboration with more than one iPhone user during a performance.

"It's not been my calling to make 99-cent apps," Redlinger, 35, says. "I'm much more interested in building a platform that people will use."

Because Mrmr is open-source, programmers can join in its evolution and add useful features by contributing to its code. It's free at the App Store, so anyone with an iPhone or iPod Touch can benefit from the work of others. And so can Redlinger, as it turns out.

"Of course I'm the world's expert on this technology," he says, "being the author of it."

This allows him some entrepreneurial leverage. Companies that want to use Mrmr for custom jobs--say to control an in-house multimedia presentation--would need to hire Redlinger or someone like him. And having the app all over the world as a free download only helps advertise his services.

"What I'm able to do is make specific Mrmr builds for specific purposes," he says. "You need to pay the rent."