I did actually play this game. Playstation Magazine way back when put it (and its sequel, Amplitude) on Demo Discs.
I fell in love with Frequency, and I still have the demo, and when I had the ability to rent games online, I did that too.
It was not the best game ever, but it was fun, and it made me expand on my musical library. A great way to kill a couple of hours and listen to some new music while you have the chance.