It is commonly assumed that low-frequency reverberation time determines the perception of bass in concert halls. Laboratory experiments were conducted to evaluate whether this and other factors influence subjects' perceptions of the strength of bass sounds in simulated sound fields. The levels of the early and late arriving low-frequency sounds as well as low-frequency reverberation times were systematically varied. Ten subjects rated the strength of the bass content of the music for each sound field on a five point scale relative to a reference sound field. Both the levels of the early and late arriving low-frequency sound had significant effects on the judgments of the bass content. Low-frequency reverberation time was not significantly related to subjective ratings of bass. The direction of arrival of low-frequency sound had smaller effects on the assessments of the bass content in the sounds. The results suggest that increased low-frequency reverberation time is not important for increasing the sense of bass in concert hall sounds. Further, the low-frequency attenuations caused by the grazing incidence seat dip effect can be compensated for by overhead reflections to increase the sense of bass in concert halls.