To really appreciate SoundCloud [3]'s vision for the future of listening, you have to see it.

The streaming service for music and sound [4]--the one with the waveform and interactive comments you've seen embedded everywhere--launches its overhauled Pro Partner program today and drops the price for its premium offerings, which are simplified to two tiers instead of five (Pro is $37.86 a year; Pro Unlimited is $129.24 a year). Pro users even get higher upload limits and better analytics. More importantly, SoundCloud has tweaked its algorithm to accommodate Promoted Profiles--brands--in its "Who To Follow" recommendation engine. It opens up a whole new potential line of revenue in exchange for a spiffy ad experience it calls "Moving Sound" (more on that in a second). Pro Partners at launch include Snoop Lion [5], Red Bull [6] Sound Select, Chris Hardwick [7]’s Nerdist, The Recording Academy producers of The Grammys, musician The-Dream, Kevin Smith [8]’s SModcast, The Guardian, Blue Mic, KQED, and Blue Bottle Coffee [9].

The SoundCloud pages for those partners [10] are where you'll find the most striking makeover--and the real innovation. SoundCloud's signature waveform is now embedded in a giant image that spans the width of the page.

Comments left by users pop up as the song scrolls along, much like before, but now the image behind the wave changes like a slideshow.

"It's really kind of a feeling-based format," SoundCloud founder and CEO Alex Ljung [11] tells Fast Company. "It's very simple but powerful."

Sound has a unique power to trigger emotions. Coupled with the right images, shown at the right moments during a track, the new visual tool has the potential to greatly bolster engagement, takeaway, social shares, and for Pro Parters that get creative--revenue. The first batch of partners are required to upload content as part of their agreement with SoundCloud. "We didn't want to have too many [brands] in the beginning," Ljung says. "I think we'll be quite selective with what they want to do with it to make sure it seems cool." The idea is that there will be quality content that users want to promote organically. But the shares get a kick-start with the promoted user feature--pricing varies from brand to brand and SoundCloud is still working out rates.

Take a look at what Red Bull Sound Select [12] did here. A song from one of its artist partners plays interspersed with text. This is what SoundCloud was teasing with its sonic banner ad [13] a few weeks back. You can also pretty easily envision Hollywood studios using this to promote films. As it works now, you get a first glimpse of production stills, then nothing until a trailer. Those stills could be accompanied by sound from a scene in the film or a director's commentary.

SoundCloud took some flack in December from hardcore creators after it launched its "Next" feature, which included features aimed at attracting consumers rather than those who upload original sounds. Attracting a more general consumer of sounds put SoundCloud on its steepest growth curve since launch, cofounder and CTO Eric Wahlforss tells Fast Company. "The next version of SoundCloud is performing amazingly well." Today's drop in price for pro users and the new visual tools for Pro Partners represent a pendulum swing back to the creator end of the spectrum.

In a lot of ways, SoundCloud is backing into its business. They never went after licenses from record labels before launching. Instead, they distinguished themselves by focusing on the whole world of sound--think: spoken word, environmental sounds, bats mating [14], Tolkien reading Elvish [15].... They were user-powered from the get-go and featuring original content before it became the rage. "Frankly we've done the hard work, which is connecting the creative community at this massive scale," Wahlforss says.

Along the way, plenty of music labels saw the benefit of having their artists' songs on the sharable, social platform, so they started posting songs there, too. But you still can't actually search very well for artists' tracks. SoundCloud has no plans to become the type of service that would compete with Spotify [16], the New [17] Myspace [18], the forthcoming Daisy [19], Rdio [20], or others. It's more focused on YouTube [21], Wahlforss says (Keep in mind, YouTube is rumored to be launching its own music-streaming service [22] later this year, too). His back-of-the-napkin calculation has Spotify adding roughly 20 minutes of content per minute. YouTube is more like 70 hours. SoundCloud's 30 million registered users are adding more than 10 hours every minute, Wahlforss says. "We're actually not that far behind YouTube in terms of the scale of things."

[Image: Flickr user NRK P3 [23]]