Algorithms and 167 000 speakers: the sound in the MSG Sphere

You can tell that concert halls are optimised for good acoustics. They have a complex geometry that distributes the sound as evenly as possible to the audience and avoids annoying reflections. A lot of wood and plaster is used, while sound-absorbing absorbers prevent unwanted echoes.

The new MSG Sphere in Las Vegas is even more difficult. This is because the spherical architecture is anything but ideal acoustically. Even in circular concert halls, the sound is extremely amplified by reflections at certain points. This is even more true for a sphere.

The square must go into the round

The company Holoplot from Berlin has installed a total of 167,000 loudspeakers in the MSG Sphere - combined into 1600 fixed and 300 mobile units. Holoplot uses 3D audio beamforming - so the loudspeakers can be controlled individually. This allows the acoustic differences at the various points in the room to be equalised using algorithms.

With wave field synthesis, sounds can also be virtually placed in the room. This allows the illusion to be created that a certain sound source is coming from a certain point.

The speakers are invisible because they are located behind the 15,000 square metre LED wall. This poses another problem: the wall is between the speakers and the audience and impairs the sound quality. The solution here is the same: Compensation through algorithms.

According to Holoplot, the result is crystal-clear, complete and consistent sound. At least a few thousand visitors will find out whether this is true after 29 September, when the Sphere opens with a concert by U2.