In this paper, the psychophysical abilities and limitations of the auditory and vibrotactile modality will be discussed. A direct comparison reveals similarities and differences. The knowledge of those is important for the design of audio-haptic systems, multimodal music applications or perceptually optimized human-machine interfaces. Literature data and own results for psychophysical characteristics are discussed. This paper focuses on the absolute perception thresholds of both modalities. The main factors which influence these thresholds are discussed: age, energy integration, masking and adaptation.