by Leo (Laewoo) Kang, Feb 2017

April 2018, at la SAT, Montreal, photography (c)


Intermodulator is a sound responsive installation that produces diverse patterns of moire image through participants’ collective and improvisational sound engagement. The system receives and analyzes the frequency and volume of different live sounds, and map them to the speed of the fans and the brightness of the backlight. Current installation is comprised of eight different modules of the fans, and each module is assembled by two fans that oppositely face to each other like a sandwich (Figure 2).

Each side of fans is connected to two different sound inputs (mic A and B in Figure 1, 2), and this module assembled with an incandescent light bulb produces diverse combinations of fan images by responding to participants’ sound (or music) engagements. When a certain resonance and tension are achieved between these different inputs, the installation produces diverse patterns of moire, which is visionary illusion caused by mutual ‘interference’ of two oppositely rotating objects or visual images.

Figure 2: One module of Intermodulator responding to two different sound inputs. The speeds of individual fan are mutually affected by each other’s sound.

Like a seesaw, which requires more than one person to appropriately enjoy it, its design of the system naturally and implicitly encourages people to use this installation in a collaborative format. This system also can be extended to multi-channel inputs by incorporating an audio-mixer through which more than two people can interact with the installation.The following videos show its alternative version where eight participants collectively improvise with the installation.
By providing a heuristic space where participants can produce interesting audio-visual performances through collaborative improvisation, this installation allow people to empirically explore the nature of collaboration and improvisation that promotes group creativity and learning.

This installation was built in the process of our art-based research project titled ‘Intermodulation [Under review]’ where different musicians, visual artists and HCI researchers collaborated to produce diverse audio-visual concerts from 2015 to 2017 in NY, USA. The main goals of this research were to understand the key features of collaborative improvisation that enable creative learning, and to explores the value and possibility of such artistic practice as a mode of HCI research and inquiry.

In this project, the author was engaged primarily as a multimedia artist, providing interactive artworks to accompany the performances of electronic and experimental musicians. Along with this art making study, we also had interview-based study on multi-media artists and musicians, including participated musicians, who engage processes of improvisation for producing their creative works.

One key lesson the author learned from this research is that collaborative improvisation has essentially ‘inter-dependent’ nature where participants actively listen to each other in the situation, and mutually adjusting their tunes depending on other’s play. Especially, good improvisation, which promotes creativity and learning, is not only achieved by building harmonic and stable relationships between those who share similar interests, but also by exploring ‘tension’ between similarity and otherness, which may periodically give rise to kinds of ‘interference’ or ‘disturbance’ to each other.

Like two oppositely facing fans that mutually interfere each other’s direction, like moire image that appears in tension of interdependent engagement, such lesson on collaborative improvisation conceptually and technically inspire the design of Intermodulator.


photography (c)


Technical Details and Settings
The system of this installation is built by assembling diverse DIY electronic components. The PSSR/ZC Tail has been used for safe control of 120vac incandescent bulbs through zero-crossing detection. For analyzing the frequency and level of individual input sounds, Sparkfun’s Spectrum Shield has been used. The speed dials in the box fans have been hacked and connected to four channel relay shields. These electronic components are connected to and controlled by the Arduino-based microcomputers. More than 2000W at 120VAC is required to run the whole installation.