I'd never heard of QSound before this. I've just been on their website and listened to the demo's. It sounds to me as if they've added some out-of-phase effects to the higher frequencies - it's different, but I'm not convinced it's better. As for compression effects, I couldn't judge on the strength of a download, but I don't (think I) have any CDs using it. What other CDs are there using this technology?