A system for generating a head-related transfer function, HRTF, dataset, the system comprising an HRTF dataset selection unit operable to select two or more HRTF datasets, a characteristic identification unit operable to identify characteristics of the selected HRTF datasets, an HRTF dataset modification unit operable to modify one or more elements of the one or more selected HRTF datasets in dependence upon deviations in identified characteristics of the HRTF datasets, and an HRTF dataset generation unit operable to generate a combined HRTF dataset comprising at least the modified HRTF elements.