Psychophysical matching techniques were employed to equate the subjective experience of motion in two roll-axis motion simulation devices: the RATS, a whole-body motion environment, and the dynamic seat sub-system of the ALCOGS, presenting motion cues through a moving seat pan. Two psychophysical techniques, cross-modality matching and magnitude estimation, yielded similar results. These results indicated that motion sensitivity increased with roll angular frequency for both simulators. However, the rate of increase at high frequencies was greater for the RATS than for the dynamic seat. These results were used to design a filter for the dynamic seat which enhanced high-frequency signal components. Tests in a roll-axis tracking task showed that performance in the dynamic seat using this filter was both quantitatively (in terms of r.m.s. error) and qualitatively (in terms of frequency characteristics) similar to performance in the whole-body motion environment.