2014 10 24, Gerhard

A multichannel audification has been performed in the Ligeti hall. 31 out of the 164 neurons can be listened to at the same time while walking around in the hall. The samples are looped and the playback speed can be varied. The loudspeaker configuration is the one that was used in the Mind the Gap event.


Before listening to the audification in the hall, StiffNeck was used to auralize the audification. When changing the playback speed, it was discovered that the signals contain a frequency at a third of the sampling frequency (ca. 14.7 kHz). When transposed downwards, this frequency becomes very audible (for younger listeners it is probably already very audible in at the "original" speed). This is why all samples have been lowpass filtered reducing the bandwidth to half of the original (11.025 kHz).


The band limitation has been achieved by converting the sampling rate of the soundfiles to 22.05 kHz and then to convert them back to 44.1 kHz using high-quality sinc interpolation (sndfile-convert).


2015 06 01, Gerhard


The artefacts decribed above were due to reading the data incorrectly (see also here).