Ensemble signal averaging is conventionally used to reduce the noise content o/ECG recordings. One shortcoming of this technique is that it removes the possibility of registering transient signals. As a consequence the simultaneous averaging of spatially related leads has been used. This relies on the recording electrodes receiving correlated signal components for reinforcement together with uncorrelated noise. We have developed a methodology for studying EMG noise reduction by spatial averaging and present results for different electrode spacings which suggest minimum separations for noise rejection.