I have to admit that when I first used PLII I wasn't that impressed. In fact I couldn't understand what the fuss was all about, the surrounds I thought were weak. It wasn't until I turned the circuit off that I realized the enveloping effect it provided. So you should notice "something" as you switch it on and off, (provided it's working properly and you have the parameters set correctly). Try Pink Floyd's "Dark Side Of The Moon" cd and see what your system will do.