What is the sampling rate for the INSIGHT and why has it been designed this way?

The data measured by the Emotiv Insight is oversampled at 2048Hz/channel and this is filtered heavily to remove all traces of environmental electromagnetic interference and then down sampled to 128Hz. The specified frequency response range of the Emotiv Insight requires a minimum sampling frequency of around 90Hz, we achieve very high signal fidelity with a data rate of 128Hz while maintaining adequate battery life.