1. A method for characterizing a suspension with particles floating therein, which method comprises the steps of performing a series of measurements, wherein each measurement comprises the substeps of generating an acoustic actuation signal in the suspension using a transmitter, registering an acoustic reflected signal coming from the suspension as a result of the actuation signal, wherein the method further comprises the step of determining a representation of a particle size distribution based on the composing of information of the reflected signals from the measurements, characterized in that the method further comprises the step of calculating for each measurement a first dataset on the basis of said reflected signal, so that said dataset contains information which represents an autocorrelation function as a function of the time of said reflected signal, and wherein the step of determining the representation of the particle size distribution comprises the two substeps of combining the first datasets into a second, cumulated dataset, which represents a sum of the autocorrelation functions which corresponding with said first datasets, and solving the representation of a particle size distribution from an expression for the second, cumulated dataset in terms of the representation of a particle size distribution.