Now Hear This

While many school districts remain unfamiliar with the technology, Ohio is ahead of the sound curve. Prompted by Flexer's work, the state has required since 2003 that districts using state funds to build or renovate schools include sound amplification in their construction plans. Districts in other states are beginning to get on board. Last year Audio Enhancement of Bluffdale, Utah, the leading U.S. vendor of classroom sound systems, sold 15,000 of them, up from 7,000 in 2002. Typical cost per classroom: $1,500. Reno, Nev., has added the devices to 52 schools over the past two years, and Palm Beach County, Fla., is using a federal grant to pay for systems in 27 poorly performing schools.

For some teachers, including Adam Loredo of Chicago's Horace Mann Elementary, there's an unexpected bonus to using a microphone: "My throat stopped being sore at the end of every workday."