Audio Technology Redefining Art

The EK 2000 IEM receivers, IE 8 earbuds and SR 2050 IEM twin transmitters were accompanied by a complex antenna system. Seventeen antennas for wireless mics, IEM and headphones were allocated among four concentrated locations throughout the station to achieve seamless RF coverage for both the performers and audience members.

Depending on the zone, model A 2003-UHF passive directional antennas were deployed with A 5000-CP circularly polarized antennas, effectively minimizing signal strength variations while eliminating multipath issues.

The “technology star” of Invisible Cities was the Sennheiser Digital 9000 wireless mic system, which delivered eight channels of uncompressed, artifact-free audio throughout the facility and captured the nuances of the libretto. The components of the Digital 9000 system included the EM 9046 digital receiver, SK 9000 beltpack transmitters and MKE 1 clip-on mics.

A fully digital transmission system, the 24-bit/96 kHz analog-to-digital conversion takes place in the transmitters. The clarity and sonic quality of the system was excellent, virtually identical to listening to wired mics in a studio control room, and it delivered rock-solid wireless performance in the notoriously tough RF environment that exists in downtown LA.

One of the four wireless antenna stations.


Sound designer Martin Gimenez specified a diverse collection of Sennheiser evolution mics to capture the orchestra’s brass and percussion as well as overall room ambience. For woodwinds and strings, including a harp, he called for several Neumann KM 184 small-diaphragm condensers, and for piano, selected a pair of Neumann U 87 Ai large-diaphragm condensers.

“Between the sonic immediacy of the headphone concept and Christopher Cerrone’s haunting orchestration, sonic transparency was paramount on our minds,” Gimenez says. “Having access to the entire range of Neumann and Sennheiser microphones proved vital and necessary in order to convey the amount of detail to each and every audience member.”

How It Works
Union Station is a busy, fully working transit station that host upwards of 30,000 passengers per day. And like it or not, for a month or so, the thousands of people who used the station were a part of the production, if only for a moment or two, as they made their way through the building. Most were completely unaware of what was taking place around them.

An actor outfitted with Sennheiser mic
and IEM.

I attended a dress rehearsal of Invisible Cities prior to its official opening. The concept could be called something like a “moveable production.” With your ticket comes the pair of Sennheiser wireless headphones. You put them on and wait for something to happen, perhaps feeling a little odd that you’re wearing a conspicuous over-the-ear set of headphones in a public place. But there are others around you with the same headgear—each performance accommodates 150 to 200 theatre-goers.