My experience to date has been in narrating instructional audio tapes of a technical nature.
Reading full length books onto tape for the blind.
Reading magazine length articles onto tape for the blind.
Although I took courses in voice when I was a young man, I have spent most of my career as an engineer, and later as a manager for companies involved in medical imaging. During that time I used my voice primarily in instructional areas related to my work.
Thirty years in technical fields and technical management gives me unique skills with regard to those projects where the material is complex or uses jargon specific to an industry.