It’s all in the title, the audio in the in-game turorials always seems to cut out before the lecture is finished. This may already be a known problem but I didn’t really find any references to it, except one dating back to 2012. Not a critical problem…
Win7 64-bit, standard Realtek HD Audio setup. Did not add a dedicated sound card to this system, and Windows auto-updating is turned on. I do have a dedicated graphics card (Nvidia GTX580), and the drivers are up to date.
Indeed that is a known problem, irritating but as you point out not game breaking at the moment. That definitely needs to be fixed when we’re polishing things up for Steam.
Ok then. Thanks for confirming.
A similar bug succeed with the test in the track: the car sounds very strange.
That’s just how the car sounds are at the moment. They’re going to revamp how they sound in the test track screen. (Judging from a ‘Little Dev Update’ video)
These car sounds are sometimes very strange indeed, I especially noticed them on the BRC testing - overreving caused silence sometimes. But that will hopefully be fixed with the next patches - with some additions 
I find the change in sound to be unnatural when decelerating while approaching a corner. But it isn’t too much of an issue.