The Anechoic Chamber

Last night, I was at Microsoft Research’s new building in Redmond, WA, as part of TechFest 2008, where Microsoft unveiled a series of research projects. While there, I toured the anechoic chamber–a room that is built to suppress echoes–which is used to research microphones and loudspeakers. “This is a room that simulates the absence of a room,” said Ivan Tashev, a software architect in the speech technology group at Microsoft Research. I walked in through two sets of doors, walking precariously in heels over a mesh suspended above the floor, which is covered by the same alabaster-colored triangular cushions that fill the wall and ceiling. Tashev’s voice seemed to come from far away as he went on explaining that the triangular shapes trap and dampen echoes before they can reflect from one of the surfaces in the room.

If you sat here in silence for two minutes, he said, you would start to hear the blood rushing through your ears and the sound of your own heartbeat. After 10 or 15 minutes, the auditory hallucinations would begin.

What’s the use of such a surreal room? Tashev explained that the room is used to research direction and sound. Microsoft has done previous research in this area: it was used for signal processing algorithms incorporated in Windows Vista that allow a user to select whether she is listening to a recording through a headset or through speakers and adjust the sound accordingly. Normally, Tashev said, listening to a recording through headphones makes the sound seem to take place somewhere inside your head. The algorithms in Vista are designed to make the sound seem to occur in front of you, as it would if you were attending a concert. To accomplish this, he said, the researchers also studied the way that the structure of a person’s head affects the way she hears sounds.

Current research, Tashev said, probably won’t appear in a Microsoft operating system until the beginning of the next decade. But the anechoic chamber and other sound research are part of two other research directions for Microsoft: Tashev said that the company is working on better speech-recognition technology, as well as technology that could improve teleconferencing by capturing and accurately relaying directional sound. If successful, the research would increase the sense of presence at a teleconference by allowing a speaker to direct his comments toward a distant listener, the way he might direct them toward someone sitting to his left.

Ultimately, Tashev said, he envisions sound systems that record and replay accurate directional sounds without requiring users to wear special devices such as headsets.