Greetings, all,
I have just perused your thread on "what is a trus contralto". My voice teacher says that 70 % of women are sopranos, about 15-18% are mezzo-sopranos, and the remaining 2-5 % are contraltos. Obviously, most of the "altos" in a choir then are mezzo-sopranos.
What determines that I am a contralto rather than a mezzo is that my voice is dark, heavy, and rich as well as low. ( My voice break is around E/F above middle C and on a good day, my high pitch is the G an octave up from there. I can easily sing tenor in my low end.) Even in head voice, my voice is heavy, so I work on nasal resonance and such to bring the sound forward.
In addition to our relative rarity compared to other female voices,it has been my experience that contraltos do not get the strokes that the high women's voices get (boo-hoo, pass the tissue). A Bass friend of mine used to say that the "S" in SATB stands for "soloist". Additionally, because there are not many parts for us in opera, we tend to seek out other types of music. And lastly,because many untrained sopranos and mezzo-sopranos sing only in "chest" voice, I think it is a common misconception that all Women singing in a low tessitura are just untrained and/or in chest voice.
Kathleen