I attended a support group meeting in San Diego, in the mid 90s. A young Trans-woman gave a sales pitch for her instructional video on achieving a counter-tenor speaking and singing voice.

As she explained the training regimen in full detail, I didn’t bother to buy the video,(VHS tape in those days).

I practiced while driving, every day,(a lot of that in SoCal).

Once I had trained the muscles to achieve the proper timbre,(the average female voice is only half an octave higher than the average male voice), I sang along, in my car, with Patsy Cline, every day. That reinforced the 'female' timbre, regardless of pitch.

26 years later, my 'Adam’s Apple' is gone. A young woman that I know, a month or so ago asked me if I could speak with my old voice, (lower range of baritone/upper bass). I tried. She said that I sounded like,”a woman trying to sound like a man.”

As a music professional, I would assume that you have access to the training method for learning counter-tenor. If you don’t, please feel free to contact me. I’ll explain it. It’s really quite simple, just takes daily practice…😍😘😇

“Male to female voice change.” by WeeziSbaby https://link.medium.com/24sKkXx2o7