An electronic article surveillance system has a receiver with a plurality of receiving coils. Each coil in the system is treated as a separate detection unit with its own noise environment which is distinct from the noise environments of the other coils in the system. The picture of the noise environment is preferably expanded to include examining noise per coil per phase. Control apparatus has facility for changing the interconnection and configuration of the receiving coils responsively to the per coil and per phase noise environment analysis. Noise analysis and coil configuration change can be practiced concurrently with EAS system operation or may be practiced during periods in which the EAS system is rendered inactive.