Working from home? Switch to the DIGITAL edition of Stage Directions. CLICK HERE to signup now!
Generic selectors
Exact matches only
Search in title
Search in content

Wireless Wonderland

Vincent Olivieri • Feature • December 2, 2013

A still from Invisible Cities

A still from Invisible Cities

The Industry’s production of the opera Invisible Cities used wireless technology to transport the audio—and the audience—throughout L.A.’s Union Station

Los Angeles is a cultural capital. Driving through its many streets and highways, you can’t help notice all of the creative projects (large and small) that are happening all around you. There are light festivals on the beach, performances in parking garages, concerts on street corners and theatre in city parks. Recently, that list got expanded with an opera performed in a train station.

An opera. In a train station. An immersive opera, in which each audience member moves through the space at their own leisure. A roving opera, where performers wander through LA’s iconic Union Station and its adjoining courtyards, singing and dancing amongst the travelers and audience members (and homeless people). A modern opera, with a score by Christopher Cerrone. A technological opera, in which audience members experience the music over high-quality stereo Sennheiser headphones and every performer is wired for sound. Invisible Cities, by Christopher Cerrone, and presented jointly by The Industry and LA Dance Project, is this opera.


Sound designer E. Martin Gimenez, second from left, backstage at Invisible Cities.

Sound designer E. Martin Gimenez, second from left, backstage at Invisible Cities.

Directed by Yuval Sharon (who is also the artistic director of The Industry), Invisible Cities is based on the novel by Italo Calvino, and recounts a conversation between Marco Polo and Kublai Khan in which the explorer recalls for the emperor some of the many exotic cities that he visited in his travels. For this production, that conversation took place in, and the exotic locales were suggested by, L.A.’s Union Station.


I was invited to watch the second run on a two-run rehearsal day, and I arrived at the train station mid-way through the first run. When I entered the station, my first thought was that nothing was out of place. Commuters still rushed to their subway trains (yes, L.A. has a subway), and travelers waited for their Amtrak journeys. However, it was not long before unusual things started to appear. Groups of people wore headphones and moved collectively, like schools of fish. Dancers contorted themselves in fits and starts. Mysterious hooded figures glided through the main hall. A man in a wheelchair wearing an old green army jacket filled the room with his voice. A large man in a hipster-plaid flannel shirt pushed him around (E. B. Brooks designed the terrific costumes). I followed the singers around until the rehearsal ended, finally ending up in a side hall that is usually closed to the general public. The rehearsal ended, the audience applauded, and both cast and audience dissolved back into the general mass of travelers, working on notes or getting a few minutes of break before the next run-through.

The Journey

The Industry is barely three years old, but it has already created a reputation for avant-garde work. Their previous piece, Crescent City: A Hyperopera, also directed by Sharon, was mounted in a warehouse and featured the work of a half dozen different visual artists. At the opening night party for Crescent City, sound designer E. Martin Gimenez, deep in conversation with Sharon, proposed a new idea for a project: what if The Industry created a piece entirely for headphones? Gimenez is an aficionado of the Silent Disco movement (where a group of people, equipped with wireless headphones, dance to the club music while onlookers watch the silent dancing mass), and he was eager to explore using the technology in an operatic environment. Sharon took to the idea, but he wanted to do the performance in a public space. Soon The Industry was hard at work planning for Invisible Cities.


The audience gathers around the orchestra as the opera starts, before touring Union Station

The audience gathers around the orchestra as the opera starts, before touring Union Station

One of the first things Sharon and Gimenez had to do was source the headphones for the audience. They wanted high quality equipment for an excellent audience experience, but Gimenez’s queries into the silent disco communities were not proving fruitful. A casual conversation with a company member opened a door to the Sennheiser Company, one of the top manufacturers of wireless technology in the world (Sennheiser also distributes Neumann microphones). The Industry pitched their idea, and Sennheiser, bowled over by the vision of the project, committed to supporting it in any way they could. Sharon and Gimenez were buoyed by this boon, but they knew that access to the high-quality microphones and wireless gear was only part of the solution; they also needed to address the infrastructure and logistics required by the massive amount of equipment that would need to be brought into Union Station. For that, Gimenez contacted Bexel ASG, an international company that handles wireless needs for companies around the world. Bexel, like Sennheiser, jumped at the opportunity to work on the unusual challenge of Invisible Cities. Andrew McHaddad from Bexel served as the project lead.


The Challenges

With Sennheiser and Bexel on board, Gimenez and his expanding group of colleagues got to work figuring out how best to deliver sound to the audience. Their task was broken into four basic elements:

Input. Everything in the opera is produced live; there is no prerecorded musical content. Using a live orchestra was important to Sharon, Gimenez, and conductor Marc Lowenstein, but the orchestra could not rove like the singers and dancers. Rather, it needed to live in one room that could be dedicated to its use, and Union Station offered a special-events room for that express purpose. The orchestra room was located a short walk from the main hall, but it fit Lowenstein’s needs and also happened to have an acceptable acoustic response (owing to cork paneling on many of the hard flat surfaces).  The orchestra was outfitted entirely with 24 Sennheiser and Neumann microphones, which were converted to digital and sent 1000 feet of fiber optic cable to the mixing console.

Invisible Cities performed in front of spectators outfitted with Sennheiser headphones who  were there to see the show—and people in the station who had no idea what was happening.

Invisible Cities performed in front of spectators outfitted with Sennheiser headphones who were there to see the show—and people in the station who had no idea what was happening.

Real Estate. In initial conversations, Union Station mandated that The Industry set up and strike all of their equipment on a daily basis. Working within that restriction, Gimenez, Sennheiser, and Bexel designed a sound delivery system that fit into three road cases. Every night, the road cases could be rolled into place and connected with mult cables. At the end of the night, the mult cables could be disconnected and the cases would be ready to store until the next performance. As the time passed, Union Station relaxed their restrictions, eventually giving The Industry exclusive access to a centrally-located retail space in Union Station, which meant that much of the equipment could be left in place between performances.  Even with that change in logistics, the nightly set-up of the sound equipment (including positioning antennas and extensive testing) required the five-person sound crew to arrive five-and-a-half hours before curtain.


Mix, Monitor, Deliver. Gimenez elected to use a DiGiCo SD11B console to handle the mix and routing. The SD11 is a rack-mounted console with just 12 physical faders, but its i/o was expanded to fit Invisible Cities’ needs. Gimenez selected the SD11B for reasons both financial and functional (the desk was spec’ed to be mounted directly into one of the rack units, simplifying the daily load-ins), but when he was able to set up full-time in the Union Station retail space, he chose to not swap out for a larger console with more faders. The capabilities of the SD11B fit his needs entirely.  Because of how spread out the performers were, there was no way that they could monitor acoustically, so every singer and dancer was outfitted with Sennheiser EK2000 in-ear monitors. The SD11 created six separate IEM monitor mixes; principal singers had dedicated mixes, with ensemble members sharing the other mixes. Sennheiser SR-2050 XP transmitters sent the signal to the IEMs. The orchestra monitored over headphones, with six channels of monitoring divided over the eleven musicians and Lowenstein.

Wireless Activities. The RF needs for Invisible Cities were mammoth and were the reason that The Industry approached Sennheiser and Bexel in the first place. Gimenez praised both companies for their support: “The relationship with them and the resources that they have given us have been nothing short of extraordinary,” says Gimenez.

The entire wireless input chain was built around Sennheiser’s Digital 9000 Series. The 9000 is Sennheiser’s flagship wireless system and uses a unique uncompressed digital audio transmission. For Invisible Cities, eight channels of Digital 9000 were used in parallel during the show. The singers wore Sennheiser SK 9000 bodypack transmitters with MKE-1 elements. One Sennheiser EM-9046 multi-channel receiver collected all of the transmissions. And of course, each member of the audience wore a pair of Sennheiser HDR-120 wireless headphones. One of the biggest technical challenges of the sound design was designing and managing the wireless antenna network. Because Invisible Cities was performed over such a large area both inside Union Station and in its adjacent courtyards, a single system of antennae would not suffice for acceptable reception and transmission. Instead, Sennheiser and Bexel collaborated closely to design multiple antenna farms that were placed strategically throughout the performance area. Some antennae were installed on the top of kiosks, and some were mounted on tall tripod stands unobtrusively in corners of the station. Bexel MAS-500 Managed Antenna Systems modules coordinated the various wireless feeds. The result was a very clean signal for the listener, even when moving between zones.

The Impressions

Invisible Cities received rave reviews when it opened, and I must admit that even though I am not an opera fan in general, I enjoyed the production and the opportunity to wander the station as I watched the performers (perhaps being able to remove the headphones and listen to the direct sound at times added to my enjoyment).

In conversations with Gimenez, he repeated continuously how indebted Invisible Cities is to Sennheiser and Bexel for their support for the production. He also praised his sound team of Ryan Ainsworth, Jackson Campbell, Kimberly Egan, Veronica Mullins, Dylan Shyka, and Nick Tipp, who worked tirelessly to perfect the sound of such a complex project.

Remembering that Gimenez proposed the headphone opera to Sharon at the opening of their previous project, I asked Gimenez what he had proposed to Sharon for their next project at the Invisible Cities opening night celebration. Gimenez would not say, but he did go as far to say that whatever it was, he suspected he would be involved.  Through his work and relationship with The Industry, Gimenez has become a necessary partner in their projects.

Sennheiser Digital 9000 Wireless Series
System for Singers

8 Sennheiser EM 9046 multi-channel receivers

8 Sennheiser SK 9000 bodypack transmitters

8 Sennheiser MKE 1 microphones

IEM for Singers and Dancers

18 Sennheiser EK 2000 IEM receivers

18 Sennheiser IE 4 earphones

4 Sennheiser SR 2050 Twin Transmitters


200 Sennheiser RS 120 wireless headphones

Multiple A2003-UHF passive directional
antennas and A5000-CP UHF antennas



The Latest News and Gear in Your Inbox - Sign Up Today!