I typically read at 300-500 wpm (I don't really subvocalise - it's not a deliberate choice, I just don't, and don't remember ever doing, when reading at a 'norm

I typically read at 300-500 wpm (I don't really subvocalise - it's not a deliberate choice, I just don't, and don't remember ever doing, when reading at a 'normal' speed), and I'm always visualising scenes and characters (there are some I can distinctly remember, years later). Listening to an audio book at regular speed, I'm often waiting for the next piece of detail, and that pulls me out of it. That is sometimes the lesser experience (for me) - I generally find it much more difficult to build a mental image at the slower pace. If I really pay attention, I can sometimes 'hear' fragments of words and individual words - it's like a partial subvocalisation (something like "I listen 1x speed plenty fast visual fill detail"). If I deliberately slow myself down (as I often do if I'm particularly enjoying a certain section, or if a section is particularly intricate), I subvocalise as normal, but at the same time I lose the visual aspects of picturing a scene. I start to hear the prose, but lose the visualisation.