Here's a suggested test to see if the Stein product is in fact changing / improving the sound of your system. Assuming this device requires power have someone other than the critical listener switch it on and off at random (without being observed) and see if the listener can detect any change by raising and lowering his / her hand. This would provide at least a first round of objective evaluation of this piece of hardware.
Stein Harmonizer's
The other night a dear friend and major audiophile brought by three (3) Stein Harmonizer's. We were simply stunned by how much they improved my system (Devialet 220/Harbeth 30.2's/Nordorst, Red Dawn speaker cables/Torus TOT AVR). The soundstage, clarity, dimensionality etc. were greatly enhanced. Has anyone experienced anything similar? I was utterly incredulous until I heard the difference/improvement.