Book 14, Question 109
Why Do Recording Studios Have Foam Wedges on the Walls?
Recording studios have foam wedges on the walls to soak up sound instead of letting it bounce! With fewer echoes, a studio can record clear sound without a roomy ring. The wedges are especially good at soaking up higher sounds.
More fun facts
- The U.S. National Institute of Standards and Technology has a room called an acoustic anechoic chamber, where scientists measure sound without echoes.
- All six surfaces of that room, even the floor, are covered by special sound absorbing wedges.
- The chamber absorbs at least 99% of the sound energy that hits its surfaces for frequencies above 45 Hz.
- The chamber has a wire mesh floor stretched above the wedges, with a control room next door for equipment.
- The room rests on 52 springs that keep vibrations from the building out.
- Its background noise is below minus 2 decibels, too quiet for people to hear.
- Scientists use it to test microphones, loudspeakers and hearing aids.
Sources: NIST
Questions kids ask
Why are the foam pieces shaped like wedges?
The pointed shapes trap sound and let it bounce deeper into the foam, where it gets absorbed instead of echoing.
Can a room be quieter than silence?
Scientists measure some special rooms below 0 decibels, which means quieter than humans can hear.