A system detects an acoustic-wave-producing downhole event associated with a pipe at an uphole location in the presence of surface noise. The system comprises: a first plurality of acoustic sensors located a first axial position along the pipe and oriented symmetrically about the pipe axis; and a second plurality of acoustic sensors located a second axial position along the pipe and oriented symmetrically about the pipe axis, the second axial position spaced apart from the first axial position. A processor is connected to receive the signals from the first and second pluralities of sensors and configured to process the sensor signals to thereby produce an output signal. The processor is configured to adjust the digital processing, based on the sensor signals, to minimize a contribution of the surface noise to the output signal.