PLANETARY RUNWAY
audiovisual installation
2009
 
Audiovisual installation for 8 loudspeakers and 8 diodes, placed along a straight line of at least 25 meters
 
A pulse sound is played through 8 loudspeakers that are placed on a straight line of at least 25 meters (longer distances are preferred). Next to each loudspeaker is an LED diode. The distance between the individual speakers/ diodes is:

speaker/ diode                   1 to 2:          4.25    meters
speaker/ diode                   2 to 3:          2.13    meters
speaker/ diode                   3 to 4:          3.72    meters
speaker/ diode                   4 to 5:          3.19    meters
speaker/ diode                   5 to 6:          4.79    meters
speaker/ diode                   6 to 7:          4.26    meters
speaker/ diode                   7 to 8:          2.66    meters

If more space is available for the installation, the distances can be multiplied by the same factor.

The pulse sound has to be delayed to the speakers 1 to 7 so that the sound arrives precisely at the same time at the position of speaker 1. The delays are necessary in order to compensate for the times that the sound takes to travel the distances. At a room temperature of 20˚C, the delay times for the individual speakers have to be:

speaker/ diode         1:                          85.8    ms
speaker/ diode         2:                          71.2    ms
speaker/ diode         3:                          63.8    ms
speaker/ diode         4:                          51.1    ms
speaker/ diode         5:                          40.1    ms
speaker/ diode         6:                          23.7    ms
speaker/ diode         7:                          9.1    ms
speaker/ diode         8:                          0.0    ms

The diodes are flashing at exactly the same times when the pulse arrives at the corresponding speaker.

If bigger distances are used between the speakers/flashlights, the delay times have to be adjusted accordingly.
The desired effect is that when somebody is standing at the position of the first speaker, all pulses are heard in perfect synchronization. Since the diodes are flashing up exactly in sync with the emission of the pulses at the individual speakers, the visual impulses will not correspond with the aural impression. When the person moves in between the speakers, the impulses get out of sync and start to form microrhythmic patters, that change with the position of the person. At the same time, it becomes evident that each speaker is in fact synchronized with the corresponding diode. However, the lights will always run in slightly irregular intervals from the first to the eighth lamp, while the perception of the pulses keeps changing.

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