Just bought 2015 hybrid with THX. Dealer played the demo THX sound button which blew my socks off. Thought I was in for a real audio experience. So this is what I found: The system has fine fidelity...sound frequency bands can be set to anyone's preferences. Fader has good range--no problem getting adequate volume in the back, although I found that I had to put the fader about halfway between center and rear to get balanced volume. Bass very good. Better than most car systems I've heard. BUT, and this is a killer: The center speaker volume is considerably louder than the side speakers. Since the center speaker combines the right and left channels, if the center speaker is dominant, it drounds out the stereo separation you would normally hear from the right and left speaker. I don't know about previous systems, but this one doesn't have any DSP settings other than "stereo" and "surround" which do nothing on satellite radio setting. You can't get to any hidden menus (press 3 and 6 on presets, etc.) that I'm aware of. It honestly sounds like a hi-fi monaural system from the early 60's. If a good car stereo system is high on your list of must-haves, this car is not for you, at least not the trim model with the THX system. I have a call into the dealer. Will post upshot.