A method and a device for signal separation. First, values of signals observed by M sensors are transformed into frequency domain values, and these frequency domain values are used to calculate relative values of the observed values between the sensors at each frequency. These relative values are clustered into N clusters, and the representative value of each cluster is calculated. Then, using these representative values, a mask is produced to extract the values of the signals emitted by V (1≦V≦M) signal sources from the frequency-domain signal values, and this mask is applied to the frequency-domain signal values. After that, if V=1 then the limited signal is output directly as a separated signal, while if V≧2 then the separated values are obtained by separating this limited signal with separation techniques such as ICA.