Reading a thesis about temperature in Organ construction I encountered this term and I didn't know anything about it before.
So I wonder what you can tell us about "vox humana".
The "vox humana" is an organ stop intended to resemble the human voice.
According to Wikipedia
The Vox humana (Latin for "human voice) is a short-resonator reed stop on the pipe organ, so named because of its supposed resemblance to the human voice. As a rule, the stop is used with a tremulant, which undulates the wind supply, causing a vibrato effect. The vox humana is intended to evoke the impression of a singing choir or soloist, though the success of this intent depends as much upon the acoustics of the room in which the organ speaks as it does the voicing of the pipes. It is almost invariably at 8′ pitch, though on theater organs it is not uncommon to encounter a chorus of vox humana stops at 8′ and 4′ pitch, with the addition of a 16′ acting as a pedal stop.
The article says about the "vox humana":
*...apart from the temperature issue dealt with here, with artistic intention ¨ can be used: e.g. in the " vox humana "- register of the organ, in which for each ¨ sound two pipes with slightly different pitch and thus sound a beating arises, which is supposed to make the human voice sound"
and I've found this interesting demonstration of the Drawbar Organ: