This looks like an old thread, but sharing incase anyone else finds this helpful because I've used audio for years to add to my workflow and use
Audeus, I heavily use it for everything because I myself learn really well audio while following along. The big thing I use it for is batch processing readings as a first pass, and braindumping questions on another document as I listen along. I basically just hit the play button and get through whatever I need to read pretty quickly. Often for non PDF information, what I will do is screenshot a bunch of material and paste it into a Google Doc, export it as a PDF and listen to it in the app. I have paid for other ones too for years and found them to get worse over time and had to switch, and most can't read images in a PDF as well for the method I like to use. I make these large GDocs for myself and get through a good first pass at 2x speed pretty quickly and make sure I watch and read along. You also have to because PDFs aren't perfect and no matter what, all these programs have some issue with junk filtering, so even ones that claim to "filter junk" don't work well in my experience. Avoid "free" programs because they don't have WORD level highlighting as the text is being spoken and are mostly mediocre and not "free" because they waste my time and make it hard for my eyes to track what is being said. That is the big one for me and I kinda credit text to speech for getting me through my undergrad and saving my degree.
Now you mentioned recordings, most of the time, I transcribe them using something like turboscribe, put that text into a Google Doc, export and use the voices I like. It's not perfect but that's just my own way to do it, and I'm not sure if I even recommend it, it's just my own style. My personal experience with text to speech tools has been basically what let me do well in undergrad and proofread all my applications.
Remember, it's still "passive learning" - you have to still be active and actually understand the information, but the first step in any process is usually not a time management issue, but energy management, and getting over that hump is a lot easier when you can just hit play and get in the zone. You also don't need to use the voice reading the whole time, often, I'll skim read a bit, then find a pretty dense area or when I get tired and I just click on the text and keep on going. That's helped me quite a bit because a lot of studying/life stuff is less about time management but more about energy management (and attention management is dependent on energy.) For me, it basically lets me have even those "off days" to read a few things and let me sleep on the material so when I read it more in-depth the next day, all of it is way more familiar.
But this is my own experience, and like anything, you have to test and try these things yourself. And also not expect them to "do the learning for you" - you still have to be involved and that is going to energy intensive regardless.
