My immediate family and some extended family know but not all of them. I rarely see most of my family and don't talk much with my extended family because we live far apart. So, telling some of my family has not been a big priority.
The tricky ones will be my grandparents. My parents and I aren't really sure how to handle this yet. My maternal grandfather is very ill, has gone blind and is mostly deaf. So, actually physically telling him
anything is difficult. My maternal grandmother has Alzheimer's so we're not sure how much she would understand or comprehend. As you can see those grandparents are a tricky case.
However, my paternal grandmother is healthy and sharp. The problem is if anybody she would take it the worst and be most unaccepting. She was the family member most vehement about my "tomboyness" as a teenager. If anything she did everything possible to make me a "girl". So, there was much fighting, arguing and rebelling with her.
Maybe now that she's older (in her 80's) she's more mellowed out now? She told me over Christmas that she realizes she doesn't have many more years left so wants to fully enjoy what she's got. This new mentality might help because isn't that what we all really strive for? To enjoy life as our true genders- our true selves?
Anyway, my family's still not really sure on when we should tell her. She did tell my stepmom that when I talked to her over the phone on Christmas I sounded like I had a really, really bad cold.

So yeah, I know what you mean about T making obvious voice changes.