None, other than self-recordings. I have been told, many times however, that I'm a natural at it. I would have to agree.
Self-taught--I have been recording my voice or simply practicing my delivery since I was a kid.
I do not purport to be an editor--I have an external, Yeti USB microphone that I plug into my computer with which I make my recordings. I have a screen for the microphone and am conscious of acoustics of different rooms vs. open air and other impacting factors (like wind and direction) Please be aware that my services are intended to be entirely for the rough or "raw" cut of the sample needed, and any additional affects or gloss will need to be added on the commissioner's behalf. I will not submit a sub-par recording, however, so initial quality is assured.
I am a large male with a great ability to deliver abundant volume and clarity, and am an enthusiastic person in general with a love for doing voice work. I am aware of enunciation, inflection, and the fluctuating canter required to make quality, natural-sounding clips and am not afraid to re-record until I achieve the sound desired.