Scientists Trying to Improve Acoustics in Classrooms

Nov. 12 -- On days when her class microphone is in for repair, teaching becomes a strain for Lizette Adkisson.

Adkisson has used the wireless microphone to talk to her 20 students over the din of a rumbling air conditioner ever since she started teaching third grade at the Fenton Avenue Charter School in Lakeview Terrace, Calif., five years ago.

Without the microphone, she senses her students drift away.

"I feel the children, especially in the back can't hear me unless I speak up," she said. "And my voice feels very tired."

Microphones Not a Final Solution

Over the past decade, schools in states across the country, including Florida, New York, Washington and California have installed microphones and speakers in the classroom to help students hear their teachers.

But many acoustical engineers say the microphones are a Band-Aid solution to a critical problem that seriously impedes a student's ability to learn.

"Wearing microphones is a solution if using crutches is a solution to broken legs," said David Lubman, an acoustical consultant based in Westminster, Calif. "When classrooms are reverberant — amplification doesn't help. It makes it louder, but not clearer."

Rather than forcing teachers to speak up over interfering noise, it's time school officials made classrooms quieter, Lubman and others argue

To spur improvements, a team of school officials and acoustical experts is putting together a list of acoustical standards to be adopted by the American National Standards Institute early next year. The hope is that schools will voluntarily try to meet them.

Lubman is also pushing to include the standards in the International Building Code, which would require all new schools or learning centers built after 2003 to adopt them.

What Was the Question?

Studies have shown that classrooms can be a hard place to listen.

University of Florida acoustics professor Gary Siebein has visited 26 different schools and about 600 different classrooms and discovered that 50 percent of the student population could not hear past the first two rows of their classrooms.