I don't have the album, but I got curious and listened to some samples on the web. The lowest note I heard was a very low D, technically D1, which has a fundamental frequency of 36.7hz. This is the low note you hear in the beginning of the title track, for example. The bass is pretty prominent and deeper in tone than than you'd hear on most recordings, even from a bass guitar, so it sounds _really_ low. There isn't a whole lot of energy at the fundamental frequency, but there's more than you'd usually hear, and the low harmonics, starting at 73.4, are pretty strong as well.
The songs are mostly in G, so if you hear a lower pitch than that D1, it's likely to be C1, 32.7hz. The bottom note for a standard bass, acoustic or electric, is E1, 41.2hz, and you generally don't hear much of the fundamental. A five-string bass, which is fairly common now, bottoms out at B0 (B zero), 30.9hz. Below that, you're into pipe organ and synthesizer territory.
Have fun, and crank up the bass,
Drew
