The method of noise reduction known as FX-Deconvolution or FX-Prediction was fust introduced by Canales (1984). Gulunay (1986) pointed out that FX is incapable of correctly predicting coherent energy when more than one dip is present. Examples show that the effect of this in the real world is not as drastic as the mathematics might indicate and FX is now widely used as an effective after stack process. (or pre-stack on fully corrected gathers).