I have had very good luck with ferrites here in New York city where there is tons of RF. I place them one by one, because they can screw up the sound if put in a place not necessary. WHat I tend to hear is the entire system quieting down. I literally have to turn the volume up after placing them. The systems seems to sound a little dull at first. Instruments are bigger and splashier with harmonics and rf on the line. With the firrites, the instruments become smaller, more focused, purer with seeminglyu less high end, until you hear something that's tryuly in the treble range range, then you realy hear it bloom in it's own acoustic envelope. My spectral dma 50 amp sounded unimpressive with a new speaker I installed. Once I realized the ferrite was out and out them back in, the magic was back, and not in a euphonic way.
