Don't let the very grown-up looking 16 floor entry fool you, that professional silence is occasionally shattered by workers who break out the ukulele for an office serenade.
Pandora is the brainchild of Tim Westergren. He's a Stanford grad, computer geek, and former rock band member who just a few years ago had trouble finding financial backers for his Internet radio station, partly because the idea seemed so out there. It's a radio station based on something he calls "the music genome."
"The genome is kind of like musical DNA. It's an enormous taxonomy of musical attributes, so every detail of melody and harmony and rhythm and form and instrumentation. We've broken music down into hundreds of these attributes," said Westergren.
Translation: these Pandora music analysts by day are mostly musicians by night. They spend all day, every day, dissecting songs note by note to expand Pandora's database of more than 800,000 songs. A database that is able to predict music individual listeners will like.
"A lot of people who use Pandora probably don't know anything about the music genome project. But what they know is it really nails the selections for them and that's based on a decade plus of this really hard work," said Westergren.
Thanks to the smart phone revolution, there are now more than 80 million registered Pandora users. The company is now moving into the car stereo business and it just announced plans to go public and issue more than $100 million in stock.
Here's how it works from the listener's side of the computer screen or your smart phone -- all you've got to do is type in the name of the artist you want to hear, like Frank Sinatra, the song comes up in a matter of seconds, and if you don't like one song, you skip to the next one and you get something else.
Bay Area music legend Ben Fong Torres was skeptical of the idea at first, but later joined Pandora's advisory board.
"People like the idea of being surprised. That's what radio used to do was surprise you with music. Pandora makes it so that it's still a possibility only the surprise is by and large a pleasant one because it's music you've already shown that you like," said Torres.
But the question for Pandora now is whether hitting the big time means this new radio will start to sound like the old one. Westergren says never.
"We think this has to be free forever. Radio has been free for decades and that's not something we're going to change," said Westergren.