This paper describes the nature of the residual background noise in ABR averages in normal-hearing subjects. The residual noise is estimated with the Fsp technique. Low-level click stimuli are presented in 2-dB steps in the range from 30 to 48 dB p.e.SPL (approximately from -2 to +16 dB nHL) and for each stimulus level, 10 000 sweeps are acquired and stored for subsequent analysis. The shortcomings of artifact rejection and traditional averaging are demonstrated. It is further demonstrated how weighted averaging can help minimize these shortcomings. Finally, it is analyzed how the number of sweeps per block influences the ability of weighted averaging to control the destructive effects of non-stationary background noise. It turns out that reducing block size from 256 to 32 sweeps per block improves the weighted averaging significantly - but with a small amount only. Minimizing the destructive effects increases the value of statistical techniques used for objective ABR detection or to control the quality of ABR recordings. It is concluded that these techniques in combination improve not only the accuracy of test interpretation but also the efficiency of clinical test time, which is becoming important for the control of medical costs.