Quick update, there was a sound recording invention that predates Edison called the phonautograph, you can find the earliest sound recording that was made in the middle 1800s. So it is possible that his voice could have been recorded but the technology was not as advanced and I don’t think anybody thought of the idea back then.
I read that his voice has calming to most. He was slow and had a bassy low voice. That adds up more than a dude back then being 6 foot 4 and having a high pitch voice.