I was browsing the website for Harmonix (makers of Guitar Hero and Karaoke Revolution), and I noticed they have one more game series whose elements are called FreQuency and Amplitude.
Unfortunately, their website has absolutely no information about what these games are. I get the vague impression that they involve music, somehow, and I would extrapolate that they're like Beatmania IIDX except that there appears to be no specialized controller.
So at the risk of sounding like a complete newbie: are these music games, and if so, what kind?
Edit: almost forgot the most important question - are they any good?