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First Amplification System in the Senate Chamber

May 15, 1933

1890 Senate Chamber

On May 15, 1933, while setting up for the impeachment trial for federal judge Harold Louderback, who had been charged with corruption, workers installed the first voice amplification system in the Senate Chamber. For a legislative body famous for its oratory and debates, much of the history of the Senate has been one of acoustics.

Nineteenth-century senators learned how to project their voices while stump speaking before large audiences without microphones. Antebellum senators were also aided by the theater-like acoustics in the Old Senate Chamber. But in 1859 the Senate moved into the current chamber, which was an acoustical disaster. Sound bounced off its recessed walls and was absorbed through its stained-glass ceiling. Similar problems existed in the House Chamber, which one representative called “the worst place in America for a man to speak.” Many fine orators, it was said, entered the chambers--never to be heard from again.

Once radio started covering Congress in the 1920s, senators began making proposals to install microphones in the chamber to permit radio broadcasting of their debates. In 1929 engineers of the National Broadcasting Company conducted a successful test recording in the Senate Chamber with large parabolic microphones placed on either side of the vice president’s desk. Washington senator C. C. Dill then introduced a resolution to place lapel microphones at each senator’s desk, but his resolution went nowhere because senators expressed concern that the microphones might also pick up their private conversations.

Journalists found this resistance a mystery since some of the senators spoke so softly they could not be heard from the press gallery. They watched the reporters of debate sprint back and forth across the chamber in order to hear two speakers debating from opposite sides. However, reporters noted that when the shoe was on the other foot, the senators’ resistance ended because they themselves were eager to hear testimony in the impeachment trial. The microphones installed in May 1933 proved their worth when one of the witnesses, in such poor health that he had to be carried into the chamber on a stretcher, needed amplification to be heard. Three years later, microphones were again placed in the chamber for another impeachment trial, but again were used only by the House managers, the defense attorney, and witnesses--not by the senators.

It took until 1971 for each senator’s desk to be outfitted with a microphone on its left side and an amplification box on its bookshelf. The original sound system remains in place today, except that in 1994 it was converted from analog to digital technology.

Senators, by the way, found Judge Louderback not guilty--perhaps because they could hear the evidence being presented.

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