Your housemate doesn't re-listen the recorded book, doesn't make edits, doesn't clear up passages, cut and rearrange unwanted silences? He is either wildly underestimating it by only taking the "talk into a microphone" part in consideration, or I feel terribly sorry for anyone listening to his audiobooks.
He's constantly listening out for mispronunciations, unwanted pace changes, mouth noises etc. He frequently has to stop the narrator, listen to it back, get them to do a whole bit again... That's why it can take up to 3 hours just to get one hour of audio down. Not 5-12 hours though.
Does the narrator need to be involved in making edits, re-listen to recorded book, cutting and rearranging unwanted silences? Other than the occasional line redo if something is flubbed or off I don't see how that involves the narrator?
It's not just the odd flubbed line, it's loads of problems. I hear a lot of stories about it. Sometimes the narrator's pronunciation of a weird name can drift, very gradually, and the engineer then has to go a long way back to figure out where the drift started, and get them to restart from there. It has to sound natural and flowing, so no you can't just re-record individual lines and splice them in later, they would stand out and it would sound shit. That's why it can take up to a few hours to get one hour of audio down. (But not 5-12 hours, he says that's a huge exaggeration.)
