I did voice recording here, long ago, and did not have a positive experience.
Fifteen years ago there was this sleazy local managing the downtown branch of a big buxiban who asked me to do some voice recordings. The pay was a bit higher than teaching English, but not a huge amount more – something like 700-800 per hour (?), when the class pay was around 550 (?), and it was hourly, yes.
I recall that he was having us record English lessons for some CDs, and when I stumbled over some obvious errors in the lesson and then read them the correct way, this sleazebag objected. I explained that the grammar wasn’t right, but he didn’t care – he wanted the CD to match the text. I objected, saying I wasn’t going to teach English the wrong way, but he insisted. That left me with a pretty bad taste in my mouth.
The time after that, I traveled the great distance from my home to the studio for a session, as scheduled, and since the recording engineer didn’t show, sleazebag postponed the session to another day. Not a penny for the voice people who all showed up, not a penny for transportation and the inconvenience.
Was it worth it? You have to figure in the extra hassles and be clear on the details before making that decision for yourself.