A/V Veteran

"The Cube" is the first stop in testing a B&O loudspeaker. At 12x12x13 meters it is the world's largest privately owned sound test room. It is not an anechoic chamber. Instead, B&O built a space large enough to use MLS measurements to a high degree of precision. MLS measures the speaker's response to an impulse. This result is then gated to eliminate the effect of the sound reflected off the walls. The reproduced and filtered impulse is then converted back to a frequency response (techies will recognize this as a Fourier transformation). The two walls of the chamber are damped, not to eliminate reflections but to speed up the time between impulses (a number of impulses are averaged for greater precision). The support structure shown here holds the loudspeaker (in the photo it's one of B&O's very tall, pencil-thin designs). The mike is visible in the distance. Measurements are made in 140 different directions.