To understand what Beats Audio does -- or what its maker claims it does -- you first have to know a little bit about the science of recording and reproducing sound.
Whether you're a fan of Gotye or Beyoncé, the music you enjoy goes through a complex, at times convoluted route from the recording studio to your ears. When you're listening to, say, "Single Ladies (Put a Ring on It)," what you're actually hearing is a bunch of different sounds -- the singers' voices, the bass line, the drums, a synthesizer mimicking the sound of a string section -- that are vibrations of molecules in the air at different frequencies. Those frequencies are picked up by your eardrums and other structures in your ear, which are capable of detecting frequencies from just 20 Hz (20 vibrations per second) all the way up to 20,000 Hz, and noticing and analyzing tiny shifts in frequency, intensity, duration and direction. They also can differentiate between parts of complex sounds such as a guitar chord. With that sort of sophisticated gadgetry connected to your brain, it's no wonder that we tend to be picky in our musical tastes [source: Whitehead].
But it gets trickier. Remember that when you listen to a song, you're not actually hearing the singer or the backup musicians, but rather a digital reproduction of them. It's not an exact copy, or really even close to it. In the studio, a producer digitally records the various players, converting their sounds into a mess of ones and zeros, and then blends them together, using record-producing software such as Pro Tools. Along the way, he actually alters the sound of the song -- sometimes subtly, sometimes dramatically -- by using electronic filters to boost some frequencies and suppress others, until he gets something that he thinks sounds good enough to rock the socks off music lovers. He may strengthen the bass, for example, or accentuate or dampen certain frequencies in a singer's voice, to make her sound smoother. The process of tinkering with frequencies to get a more pleasing combination is called equalization. The resulting digital collage is then compressed to create the MP3 file that you download [sources: LeLoup and Ponterio, Self].
But that's just part of the aural journey of a song. It goes through other filters, including your headphones and/or your computer sound card and speakers, and they act as equalizers, too.