Mathematicians Solve the 'Cocktail Party Problem'

August 22, 2006

Officials at the CIA and scientists around the world have pondered the "cocktail party problem" for decades. How could they separate one sound - perhaps a voice - from a group of other recorded sounds, perhaps a multitude of voices at a cocktail party? Now, two researchers at the University of Missouri-Columbia have found a mathematical solution to this problem.

"Theoretically, our solution says you should be able to pick up voices on a squeaky old microphone and then separate them all out so that you can hear what each person is saying in his or her own voice," said Peter Casazza, professor of mathematics in MU's College of Arts and Science. "This is a very old problem, and we have the first mathematical solution to it."

Casazza and Dan Edidin, also a professor of mathematics at MU, worked with Radu Balan of Siemens Corporate Research to solve the problem. Their solution shows that it is possible to separate voices and still retain vocal characteristics. Researchers had previously found a solution for separating and reconstructing voices, but they were only able to reconstruct the words spoken, not the characteristics of the voice itself.

"Our solution is called 'signal reconstruction without noisy phase,'" Edidin said. "In speech recognition technology, a 'signal' could be a recording of 25 people in a room talking at the same time. Our solution shows that we can pull out each voice individually, not just with the words, but with the voice characteristics of each individual. We showed that this 'cocktail party problem' is mathematically solvable."

Although Casazza, Edidin and Balan do not have a computer program that can do this automatically, they hope to find a way to develop one. Currently, their solution runs on a computer, but the process cannot be easily replicated or distributed.

"The computer we use is doing the work without an algorithmic program. It uses a system called a neural net, which is designed for the computer to teach itself. Basically, it works on trial and error," Casazza said. "This isn't consistent and cannot be duplicated easily. We need to find a way to design an implementable algorithm that could do this consistently and quickly."

Casazza said that there are already programs that can separate and reconstruct voices, but they are not completely reliable. For example, such programs have difficulty separating voices with similar pitch characteristics. A program using the researchers' solution would be more exact.

Source: University of Missouri

Explore further: Study shows people are not good at recognising voices

Related Stories

Study shows people are not good at recognising voices

June 19, 2017

"Alexa, who am I?" Amazon Echo's voice-controlled virtual assistant, Alexa, doesn't have an answer to that – yet. However, for other applications of speech technology, computer algorithms are increasingly able to discriminate, ...

New audio codec enables unprecedented voice call quality

May 30, 2017

Smartphones can do almost everything you want, but their poor voice quality is still a vexing issue. Fraunhofer researchers have helped develop a new codec to banish this problem. Their solution raises voice quality to an ...

How to hold AI accountable for its actions

June 1, 2017

(Tech Xplore)—A trio of academics has written and published a Focus piece in the journal Science Robotics on the need to hold artificial intelligence systems accountable for their actions. Sandra Wachter, Brent Mittelstadt ...

Gadgets: Gifts for Dad—that he really wants

June 8, 2017

You think you really know what your dad wants for Fathers Day but really, you don't. Let me fill you in on what he really wants; you can't go wrong with any of these.

Recommended for you

UN says world population will reach 9.8 billion in 2050

June 22, 2017

India's population is expected to surpass China's in about seven years and Nigeria is projected to overtake the United States and become the third most populous country in the world shortly before 2050, a U.N. report said ...

The story of music is the story of humans

June 20, 2017

How did music begin? Did our early ancestors first start by beating things together to create rhythm, or use their voices to sing? What types of instruments did they use? Has music always been important in human society, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.