Piercing Brightness for Power and Clarity
Now, if you want to be heard above a lot of background noise, without relying on the booming strength of a masculine voice, you will need to add a piercing brightness that will give your voice more power and clarity while also making it more feminine at the same time.
The secret is a singing technique known as vocal twang. It sounds almost like nasal resonance, where the sound goes through your nose, but it is not. Instead, vocal twang is created by squeezing what is known as the aryepiglottic sphincter (or AES), which is right at the top of your larynx, above the vocal folds. You can see and hear the difference dramatically in this video, showing the throat of a female singer as she first hums (nasal resonance), then sings normally, then sings with a very pronounced twang.
Learning Twang Through Imitation
The best way to learn this is through imitation. Quack like a duck, cry like a newborn baby, or say "I AM A ROBOT" in your best robot voice. They may not be pretty, much less feminine, but all of these are great examples of vocal twang pushed to an extreme. And you want to learn the extreme and then dial it back from there - it is a lot easier that way.
So take a moment to try a few quacks, to cry like a newborn, and talk like a robot. Then watch this video and follow along with the singing exercise at the end.
Seeing Twang on the Spectrogram
Open up the Spectroid app, and say "uhh" in a relaxed voice. Notice where the yellow lines appear on the scrolling spectrograph. Then try saying "quack" like a duck or "I AM A ROBOT" in a robot voice - something with a lot of vocal twang. If you have done it correctly, you will see a bright yellow band of lines appear past the 1000 Hz mark. The more you constrict the AES, the brighter the yellow band will be and the more you will hear a harsh edge to your sound.
Watch this video for a great example of this, starting with a dark "uhh" and gradually raising the larynx, raising the tongue, and then adding the vocal twang for maximum brightness.
Twang Practice and the Nose-Pinch Test
With Spectroid running, try to imitate the video and say "uhh" in a relaxed voice and then gradually slide into a harsh, twangy "ehh" like a duck quacking, and back down to a relaxed voice again. Watch the spectrograph and try to get that yellow band as bright as possible when you add the vocal twang.
Then pinch your nose shut too, so you do not accidentally cheat by using nasal resonance instead of twang! You should be able to do this just as easily with your nose pinched shut - otherwise you will end up sounding like Squidward, as in this video.
Then try adding different degrees of twang to your speaking practice, to see how it feels and sounds. You could go all the way and sound like SpongeBob SquarePants, take it out completely like his friend Patrick, or add just a hint of it and sound, well, more feminine. See what you like!
Twang for Singing
Vocal twang is also really great for feminizing your singing, if you are into that. Skillful use of vocal twang can turn a weak falsetto into a powerful head voice, and increase your upper range by an octave or more. It is also the secret behind CeeLo Green's distinctive singing voice, combining a dark oral resonance with a lot of bright vocal twang and a bit of nasal resonance, as you can hear in this video. If you start there and then brighten your oral resonance with a raised larynx and tongue, you can sound like a female singer. Seriously.