Open Air

Prepared By Aisling Kelliher for xsead

Open Air

Open Air was an interactive artwork that used participants’ voices to transform the sky over Philadelphia.

About this work

"Open Air was an interactive artwork by Rafael Lozano-Hemmer, commissioned by the Association for Public Art. The piece allowed participants’ voices to transform the sky over Philadelphia. Using [the] website you could record a voice message and listen and rate other entries. The higher rated messages were played-back over the Benjamin Franklin Parkway using 24 powerful robotic searchlights that reacted, both in brightness and position, to your voice’s frequency and volume.  Every night from September 20 to October 14 the project made huge light formations, visible from 10 miles away, that were automatically controlled by your voice."

- From

This piece brings together many of the facets of Lozano-Hemmer’s work that he has engaged with over the past 15 years. Debuted in Philadelphia in 2012,  the work allows people to record short audio messages by speaking through a microphone or by leaving voicemails. After recording short 30 second snippets of their voice, this audio is then projected through speakers in a public venue, and also translated from the audio spectrum to the visible spectrum through a search light. Over the whole city you can then see the audio snippet rendered in light form.

While each snippet represents an individual’s voice, these voices could be somebody in the space, somebody participating online, or famous people from around the area who related to the ideas expressed in this work and recorded their voices for it. As a result, it has this very nice dynamic between realtime/not-realtime, in-situ/not in-situ blasting out over the whole city. 


Being at the home of the Liberty Bell and where a lot of the generation of the ideas on which the United States is founded occurred, the piece has a bit more of a political dimension to it as well. OpenAir, by allowing a broad participatory model, voices the artist’s interest in the democratic process. What you say might not be that meaningful but over the course of a day and by participating with all these other people, your thirty seconds is just as equal and meaningful as anybody else's.

This kind of participation allows people to engage in a kind of civic discourse that we might not necessarily get either in the online or in the physical world anymore. We live in a very polarizing society so having something where you have 30 seconds to say whatever you want and your voice shows up over the whole city; there is something very lovely about the grandness of that. To do something on a really grand scale. 


As OpenAir is both monumental in its challenges and scale, a big component of this piece is how to get cities to agree to do this type of work; to do it flawlessly when it has so many potential possibilities for public failure. There is something quite brave about doing large-scale works within a city. To be able to create works which are still delightful and intriguing to people at that scale is quite a challenge as well.

Technical Architecture for the Realtime System in Open Air


For an engineer or a computer scientist, or anyone who works in signal processing, Open Air is a great example of the huge technical challenges that are present, particularly in dealing with real-time systems. For example, when dealing with all of these different modalities, to get a system to work consistently in a whole slew of different settings is a non-trivial challenge. I can imagine that it's something that an engineer would find incredibly compelling to do; from dealing with timelag, to the vast disparity in peoples voices, to how do you create a system you can see for miles around but is legible in some meaningful way.

Further Reading

  1. Project Site at
  2. Rafael Lozano-Hemmer's description of the work
  3. See the work at
  4. Behind the Scene's video -
  5. Technical Description of the Project -

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Acknowledgements & Credits

Rafael Lozano-Hemmer, "Open Air". Commissioned by the Association for Public Art, Philadelphia, 2012. Photo by: James Ewing

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