What's the lowest analog audio sound that a CD/44.1kHz audio system can make?

Question

CDs, and other 44.1kHz sampling audio systems, can produce a maximum sound frequency of 20khz in the analog audio range (I'm not sure how the maths goes, but that's apparently true). My question is, whats the minimum frequency you could produce with a 44.1kHz sampling audio system? Is it 20Hz which is roughly the lowest analog audio sound humans can hear, or can it go lower into the infra-sound range?

Of course the CD/sampling system's frequency range would be restricted by the range your speakers/headphones can produce, but I'm more interested in the CD/sampling system's limitations.

Answer 1

You can encode any frequency down to 0 Hertz (DC signal) in the digital signal. Most real-world recording and playback systems will not go this low unless you modify them in some way. The frequency content below around 20Hz or so is not considered to be music (at least not by most people), so both recorders and playback devices has high pass filters or other mechanisms. Exactly how it is done is dependant on the actual implementationer. The original standard for CD-s the Red Book, I believe specifikt 20Hz as the lower frequency.