Hey!
So, I'm regularly heard as male even though I have trouble passing face to face. Since I do a lot of my work over the phone it was a really really important thing for me to get a hold on pretty early. For the record, I am completely pre-everything and the only bits of transitioning I've done have been through things like voice/speech reformation and dressing differently.
So here's what I've learned -- there are a lot of parts to sounding male/manly. I'll explicate on some of the things I've found most helpful below:
1. Bet you're thinking I'm going to start with pitch. Well, I'm not. Nope, I'm starting with the S's. S's are important. There was a study done not long ago by Colorado State University I believe that compared a trans*guy & a cis guy saying the same sentence. They both spoke at the same register but the former was unilaterally designated female and the latter designated male by listeners who did not know the subjects. The study found that this was largely due to the pronunciation of the S sound. Societal speech patterning for women teaches them to keep their mouths tighter and tongues higher when S-ing. Men on the other hand are "taught" to keep their jaws more relaxed and their tongues lower which causes more of a soft Z sound than the sharp S sound that women often make. This is totally workable.
2. Obviously, male voices are often deeper as well. You can do some work with this as well. your vocal chords are essentially a string instrument. To make strings have a higher pitch you tighten them and to lower the pitch you loosen them. So, first and foremost ... relax. Secondly, practice practice practice. Try singing some scales at a slightly lower pitch than your normal range. You do not have to be a fantastic singer to do this just practice when you're alone if you don't want people to hear. As you strengthen and loosen your lower chords you'll find it easier to go deeper. Don't try to go too low all at once though as unnecessary strain can damage your chords and potentially make it harder to reach a lower pitch over the long run. Also, keep those chords lubricated. Drink lots and lots of water. I also frequently do a mixture of water, lemon and honey at night. There are a lot of resources out there for singers on how to keep your vocals in good working order as well and those would be a good thing to take a look at.
I also do some work on this by imitating an actor that is slightly lower than my normal vocal range (Kevin Spacey in my case).
3. Pitch isn't everything though. Males also have a tendency to speak more through their nasal passages. This does not mean that you have to speak like Steve Urkle but the tiniest move from breathier (feminine) to only slightly nasally (masculine) can help a great deal.
4. Slow down. Guys are socially conditioned to speak more slowly than women. Not as easy to change as one might think but still doable.
5. Along with all of the things I have already said, how guys talk is not entirely about the sounds produced. Humans do roughly 55% of their communicating through body language and non-verbal cues. That said, watching how guys talk is just as important as listening to them.
We, as people, are the great imitators. It, like most other things in life, just takes time, patience and the willingness to keep trying.
Hope this helps.
