At the opening in STUK a white carpet covered the floor to reflect the light that illuminates the steel sheets. Indirect lighting is used to avoid mirror effects and to accentuate the original steel drawing.
This white field marked the boundaries of the set-up and thus it created a stage. People took the opportunity to find positions to mark their act of thinking.
Opening of ‘Staalhemel’ at arts centre STUK in Leuven, Belgium.
The installation received nearly 1100 visitors in 5 days. On October 7 Christoph De Boeck presented a lecture on the working process alongside the researchers from IMEC, Wolfgang Eberle and Lindsay Brown, and David Garcia with notes on collaborations between artists and scientists.
staalhemel @ STUK, frontal view
The visitor’s brainwave fluctuations produce a dynamical distribution of taps over the grid of steel objects. The steel matrix is suspended at 2m50, typical for ceiling height. It is important for visitors to walk below the steel sky and experience the acoustic shifts in direction. ‘Staalhemel’ was originally conceived as an immersive sound art project. When visitors watch the whole of the installation frontally as one total object and from a distance, they will only hear the sum total of acoustic reflections from 80 pins hitting on steel. This acoustic monolith is very diffuse, shapeless and relatively loud. When however the visitors pass below the matrix, sound sources become very defined as they hear the pins directly above their head changing their frequency. Visitors are enveloped by a dynamic acoustic cloud of which details change when they move position.
Images from the first build-up at Arts Centre Netwerk in Aalst, Belgium.
Extended electrode 10-20 positions
A definite selection of the electrode positions has been made. IMEC hardware now allows for transmission of up to 8 channels simultaneously. Electrodes for the following positions will be provided in the headset: FP1, FP2, F7, F8, C3, C4, O1 and O2. Almost all of these electrodes can be integrated into the headband section of the headset, only C3 and C4 will be mounted on top of an arm extending to the upper half of the head. Ground and reference electrodes are placed just behind the ears. It is not entirely clear if we are going to need all of the eight available channels. Work has centred upon finding electrode positions which deliver the most efficient data, e.g. in respect with the relationships between pairs, or because of the robustness of the signal. Lowpass filters remove the airborne and omnipresent 50 Hz hum from electrical mains and other background noise that interferes with the reading of microvoltages on the scalp. Signal processing algorithms are written to treat the raw data and return scaled events to the Max/MSP computer which controls the pins on the steel segments.
Soon we will start analysing the brainwave content of these areas in order to map significant data into a format that is meaningful for the distribution of sound.
The international 10-20 system is based upon a division of the head from nasion (the point between the eyes on top of the nose) over cranium (top of scalp) to inion (the bump on the lower rear part of the skull). The “10-20″ refers to the percentages that delimit the electrode positions on this line that traverses the scalp.
Here is a more graphic representation:
electrode positions 10-20 frontal and lateral
20 channel EEG event
Brainwaves know different frequency ranges. Dynamic synchronic or asynchronic changes measured over a certain number of channels, can refer to certain events such as perception and recognition of images and objects, motoric intention or mental concentration.
The following frequency ranges are typical for EEG reading:
Alpha 7.5-13Hz Alpha waves are associated with relaxation. The amplitude of alpha waves ranges between 10 and 50 mV.
Beta 13-40Hz Beta waves are associated with alertness, arousal, problem solving, and concentration. Beta waves are fast but low amplitude.
Delta 0-4Hz Delta waves are associated with deep sleep. They are a high-amplitude, low-frequency wave, and are generated by the lack of processing by neurons. Delta waves can also be found when examining a comatose patient.
Theta 4-7Hz Theta waves are associated with sleep, but can also be associated with anxiety, epilepsy, and traumatic brain injury.
Mu 7-11Hz Mu rhythms are associated with the motor cortex, and can be used to recognise imaginary motor movement.
A visitor walks under a sky of steel segments.
Hammers are mounted on top of the steel – they respond to the brainwaves of the visitor.
Visitors receive a wireless EEG brain scanner one by one, while others can watch and listen.
Previous installation project (2007) by Christoph De Boeck.
In the interactive installation timecodematter the visitor enters an arena that is bordered with vibrating sheets of massive steel. The steel objects are pulsating with low frequencies and they react to the approach of persons. The acoustic energy in this installation is both penetrating and intangible: the resonant properties of twelve different steel sheets respond to the low frequencies and produce a conjuring effect.
In this set-up De Boeck plays an electronic music concert with Yves De Mey as the duo Audiostore & Eavesdropper.
The segments suspended at a height of 2m50 are made of hot rolled steel sheets. The heating process leaves traces of discoloration on the surface. These colour gradations form patterns that mark the sky.
Contiguous segments derived from one single original sheet will be dislocated so as to accentuate the puzzle-like aspect of our consciousness.
All pieces have been cut to the uniform size of 700 x 700 x 2 mm. These dimensions deliver a rich musical spectrum when the plate is struck with a pin.
dorkbot presentation
On October 28, 2009 Christoph De Boeck presented notes on the creation process of ‘Staalhemel’ at dorkbotBRU at iMal in Brussels, a gathering of technologically minded artists and interested spectators. This session was recorded and can be watched here:
Still from the presentation at dorkbotBRU
Or via this link:
http://www.ustream.tv/recorded/2442258
Info on dorkbot and other meetings at iMal:
http://www.imal.org/rendez-vous/