I think he is talking about the missing fundamental effect. If the fundamental frequency is f, there will be harmonics at 2f, 3f, 4f, and so on. Even if your system can not produce the fundamental (as has been pointed out, the bass note on a piano goes as low as 27.5Hz), it can definitely produce the harmonics which is how you perceive the bass note. Your brain fills it in.
I can listen to piano on my iPod earphones which definitely don't go as low as 27.5Hz, but I can still "hear" bass notes on the piano.
There are products out there that take advantage of the missing fundamental effect by boosting the harmonics, giving the sensation of more bass.