To reduce a number of required channels for a survey system having seismic sensors, the seismic sensors are partitioned into groups of corresponding seismic sensors. An aggregation unit applies different transformations of signals of the seismic sensors within a particular one of the groups. The differently transformed signals within the particular group are aggregated to form an aggregated signal. The aggregated signal for the particular group is transmitted, over a channel of the survey system, to a processing system.