I started with 1 Schumann, then 2. I enjoyed the small improvements they made, then tried the FEQ. The FEQ was about twice as effective in my system. Both require a lot of experimentation in finding the best location. I discovered that my FEQ works best located between my speakers and about 3 feet high and a couple feet out from the wall. Adding 2-3 sets of Synergistic HFTs brought out even more soundstage improvements. I also tried using both the FEQ and Schumanns together, and the FEQ did seem to work best on its own. They are expensive, but once I lived with them for a while, there was no taking them out. I got a bit of upper high frequency roll-off with the Schumanns, but they did improve the soundstage.