The lecture is good, but the volume is really sooooo low. When I'm listening to this and a Windows notification pops up, I'm really surprised. I don't know why the volume is so low. I have no shame because I'm listening to it for free, but it's really so low. This is the loudest lecture I've ever listened to. I usually listen to music with the volume at 15~20, but this one has to be over 40 to be at a normal listening level.