How to Hide an Empire: A History of the Greater United States

by Daniel Immerwahr

In industry after industry, the world tuned itself to the United States. This happened literally in music, where countries bickered over the pitch of a concert A. The United States had been tuning its instruments to an A of 440 hertz since 1917. But continental Europe was officially tuned to the “French pitch,” a slightly flatter A of 435 hertz, closer to the classical pitches of the eighteenth and nineteenth centuries. Austrian delegates pushed for A435 at the United Nations. Yet with U.S. recordings flooding the market and the U.S. government broadcasting a pure A440 tone around the world from powerful radio stations in Maryland and Hawai‘i as a “service” to musicians, the Austrians stood little chance. Today, except for those playing period instruments such as baroque flutes or older church organs, A440 is the law of the land.