Short answer
Use a synthetic voice when the audio changes every week or runs to thousands of lines, and a human voice actor when the audience has to feel something. Many projects use both.
01When a synthetic voice fits
A synthetic voice turns text into audio quickly and keeps the same voice across thousands of lines. That suits notifications, internal training, product catalogues and anything that changes every week.
It also makes some projects possible at all, such as an audiobook backlist that would never fit a studio session.
02When a human voice actor fits
A human actor reads intent: sarcasm, warmth, a pause that sells. Advertising, brand film, drama and documentaries, or anything where the audience must feel something, ask for a person.
A human voice can also be directed live, so a note on the take changes the performance.
- Many lines or frequent updates
- Fits a synthetic voice.
- Emotion and brand
- Fits a human voice actor.
03A simple test
Ask three questions. Is the audio changing every week? Does it need to move the listener? Will it be public advertising? If the first is yes and the other two are no, a synthetic voice is a good fit. Otherwise start with a human actor, and switch to a synthetic voice later for updates.