Disclosed is a method of adjusting a supplementary data signal (wm(n)) to be embedded in an information signal (x(n)), for example an audio signal. The method comprises the steps of determining (107) a relative magnitude (g(n)) of a first property function (Mx(n)) of the information signal averaged over a region of a predetermined size and a second property function (M.sub.wm(n)) of the supplementary data signal averaged over said region; and adjusting (407) the supplementary data signal according to the determined relative magnitude.