I found this thesis which is probably the most thorough, some would say dense, exploration of voice vs social and biological gender I've ever seen.
Only read the intro's, discussion, conclusion of each chapters, its the only one
relevant to a non expert reader. You can read the general conclusion, but its hard to follow it if you haven't read the chapter discussions.
http://www.lotpublications.nl/publish/articles/000035/bookpart.pdfOne of the interesting conclusion is that masculinity can be transmitted through voice, but not femininity, which is very highly associated to the biological gender of the speaker.
Meaning, if you look in any way male, it won't matter how feminine you speak, it won't transmit femininity, only make you more undifferentiated, not more androgyne (they won't place you between feminine and masculine, but some kind of modified male). My own opinion is that this will classify you as a gay male.
So, to sound androgyne, if you are male, you have to significantly change your presentation towards the female side.
But, for a woman, its easier, since masculinity is not as typed, you can get away with a gender neutral presentation and some speach modifications.
In the article, they talk about two types of speach mods,
- Those are linked to the identified biological gender: Loudness and pitch.
(So, a woman to sound more androgyne should speak slightly louder, and at a slightly lower pitch (maybe 1/4 octave lower)).
- Those are linked to the identified social gender: loudness, pitch, tempo and harshness.
(So, a woman to sound more androgyne should slightly up the tempo, not vary the tempo too much (less variance in tempo in man than woman), have a slightly harder attack (less breathy) and less higher harmonics (this is a bit harder one to do than other parameters).