In stark contrast to the reverb chamber, NPL also have a semi-anechoic space. Large, foam wedges line the walls and ceiling of this room. They trap and soak up all the sound that hits them, making a room that has almost no echo at all (except for any echoes produced by sounds bouncing off the floor).
Sitting in this ‘dead room’, our ears took a welcome break from the reverb in the other chamber. You can hear the difference between the reverb and semi-anechoic chambers – and hear a musical saw played in both rooms – on the BBC interview.
Relaxing in the semi-anechoic chamber at the National Physical Laboratory
Lost in space
Gavin snapped this picture of Sarah and Stephen relaxing in the semi-anechoic chamber. As there are almost no echoes in this room, its acoustics mimics the effect you’d get if you were suspended in mid-air (an anechoic chamber is often called a ‘free-field’ room). But oddly enough, speaking in this room makes you feel very claustrophobic, even if you close your eyes. Humans aren’t used to hearing genuine free fields so perhaps that’s why we find it confusing.
In the film 1997 film Titanic, the survivors are in a semi-anechoic field – i.e. the middle of the ocean – after the ship has sunk. But the sound engineers made their voices echo. I remember being more confused and inquisitive about this than interested in what happened to Leonardo DiCaprio.
