USC Professor of Electrical Engineering Chris Kyriakakis
USC Viterbi Professor of Electrical Engineering Chris Kyriakakis helped pioneer a state-of-the-art audio application called “Audyssey,” which employs psychoacoustic technology to revolutionize the way we listen to music. By downloading the 99-cent Audyssey app to a smartphone or iPod, music lovers can enjoy pure, uncompressed studio-quality sound with nothing more than a pair of standard earphones. Is this too good to be true? USC Viterbi Reporter Conrad Wilton sat down with Kyriakakis to find out.
How does Audyssey enhance the listening experience?
Audyssey has developed several technologies to address some of the key problems in audio, acoustics and psychoacoustics – the human perception of sound. When loudspeakers in a room or a car transmit sound, multiple reflections of that sound enter our ears at different times. These reflections are a form of distortion that causes muddy bass, muffled voices and other problems. Not only is the sound degraded, but the level of degradation is also different for every listener depending on their hearing ability and the acoustics of their room or car. Audyssey can automatically find and correct these problems for a wide listening area so every listener can enjoy an enhanced audio experience.
Additionally, another problem Audyssey attacks is the way music is created. In the studio, mixing is done at very high listening levels. However, when we listen at home, in the car or with our headphones, the volume of the music is significantly less than it is inside the studio. This presents a problem in that human hearing is very different at lower volumes than it is at higher volumes. As a result, the balance between the bass and high frequencies that was designed in the studio is lost when we turn the volume down. Audyssey developed a technology to restore this balance by modeling human perception and adjusting content in real time to deliver pure, studio-quality sound.
How did you develop the Audyssey technology?
One of Audyssey’s main objectives is to develop technology that improves the performance of headphones. To achieve this goal we first analyzed the sound in calibrated studios via high quality speakers. Then we injected that sound into the ear canal of an artificial head to better observe how humans perceive the sound.
Finally, Audyssey developed a large database of over 200 types of headphones by measuring every model and creating an acoustic profile for each. We then used this knowledge to develop innovative technology that calibrates each headphone model so the sound it transmits is as close to the original studio sound as possible.
Audyssey Allows Songza Users to Calibrate Their Headphones
What was the greatest challenge you faced when developing Audyssey?
Our biggest challenge was finding a way to develop an automatic method to create the headphone profiles. There are several types of headphones (in-ear, on-ear, over-ear, etc.) and each type delivers sound differently.
What separates Audyssey from competing software that supposedly enhances the listening experience?
Other audio companies in this area provide sound effects such as bass boosts, vocal enhancement, and “virtual” surround sound. These effects may be desirable by some listeners, but they change the sound from the original. Furthermore, because each headphone has unique acoustical characteristics, these effects are not consistent from song to song.
Audyssey has focused on developing technologies to remove the problems that degrade sound quality instead of just disguising them with special effects. These problems are very difficult to solve, but once they are removed the improvements in sound quality are dramatic and can enhance the listening experience for every song in your library.
How can listeners customize Audyssey to fulfill their personal preferences?
We allow users to set their preferences consistently without having to readjust for every song. Audyssey developed an intuitive tone adjustment control called “Tilt” that lets the listener fine tune the balance of high and low frequencies with a single slider.
Which mobile devices currently support Audyssey?
In Japan, every Android mobile phone sold by NTT Docomo comes with Audyssey technology built into its media player. Other mobile operators are planning to offer Audyssey to their users in the near future.
The most advanced version of Audyssey for mobile devices is now available on the iTunes app store. It’s an application called AMP (Audyssey Media Player) that applies Audyssey to your iTunes library on your iPhone, iPad or iPod Touch.
Why does it only cost 99 cents to download Audyssey’s state-of-the-art technology? Is there a catch?
There’s no catch. We want everyone to enjoy music the way it was originally made.
In addition to mobile devices, what other industries are currently using Audyssey to improve their sound systems?
Audyssey can be found in about 75% of home theater systems. IMAX is now using Audyssey to calibrate their theaters and deliver an enhanced sound experience to their viewers. Additionally, top automotive manufacturers in Europe are using Audyssey to remove acoustical problems in their cars. Television manufacturers are using Audyssey to enable thin TVs with small speakers to deliver higher sound quality. Streaming music services are starting to include Audyssey to improve the quality of music delivered to their listeners. Songza, one of Spotify and Pandora’s lead competitors, has already incorporated Audyssey into its programming.
Where do you see Audyssey going in the future?
The future is in applications. Hardware of all types is quickly becoming a commodity and differentiation among competitors will come from compelling apps. Audyssey will be the company that continues to innovate and ensure the quality of the audio experience is as high as possible regardless of the playback device.