Ok using a few basic sound engineering principles I really can solve this for you.
Amongst my many talents I used to be a BBC TV recording engineer. (My first job in television). One thing we were taught on our first training course was about the use of various different types of microphone and how to exploit them to get the desired sound profile for an artist or actor.
For you there is a very useful little effect called BASS TIP-UP - it's basically exploited a lot by sports comentators who want to sound butch, and by that man from hollywood who does all the action film trailers, you know the ones that start with a line, in a deep resonant voice, like:
"it was a time for heroes...."
The trick is to get a proper lip mic (this is literally a mic so insensitive that the only way it picks up you voice is when it is in contact with your lips) If you speak into one of those - or indeed any mic held REAL close then you will get bass tip-up and your voice will naturally sound a lot more resonant and much deeper. They can be bought from any decent sound recording shop and they aren't that expensive.
By contrast if you were an MtF looking for the reverse effect what you would need is a sensitive and selective hypercardioid mic placed at some distance away (because a distant mic always loses the bass frequencies.)
I hope I haven't made that sound to complex. It's actually quite simple
Close mic when you want lots of bass
Distant mic when you want to lose it!
Try it - I promise you it works.
