The HelicopterBand performs while navigating four radio-controlled helicopters. Members are TANIGUCHI Akihiko, YASHIRO Satoshi, Koichiro Mori, and SEKIJIMA Naoto. Each performer's helicopter is equipped with a distance sensor, and the performers control the square wave frequency based on the distance of their helicopters in flight from the ground. Each player performs by navigating his helicopter according to a musical score.
Square waves are a type of sound that cannot be reproduced in today's FFT*-based digital audio environments. Inaudible as linear frequency transformation, it is emitted through aliasing** in the form of sine waves of different frequencies.
The band interprets such vaguely outlined square wave as a kind of sound that dangles in the space between sine wave and noise, and makes use of the non-linear frequency transformation as a peculiar, latent tonality of the 44.1 KHz sampling rate.
* FFT (Fast Fourier Transform): Transformation of audio signals through decomposition into sine waves of different wavelengths.
** Aliasing: Phenomenon of virtual sounds not contained in the original data that surface when sampling sequences of analogue audio signals as digital discrete values.