I posted the first positive feedback way back when the initial design by Dakiom released, although actual product experience reported as review on the website. I believe my feedback should have properly credited Dr. Dao not Mr. Dao, but his level of academic attainment was unknown to me at that time.
One on the CDP outputs and one on the receiver amp's speaker output terminals created a more solid or three dimensional illusion of performers in the room along with enhancing clarity, and most of all it really elicited a musicality from recordings that previously sounded rather dull. This was true for the two plain vanilla systems that I used as test systems since they were uncomplicated, free of tweaks, and in need of help. Upon removal, to check whether there really had been so much improvement, the sound returned to being trapped between the speakers and a dullness replaced the toe tapping quality.
After all these years, the website has accumulated many amateur and professional reviews which mention benefits to sound systems of varied pedigree. An affordable tweak that has proven itself many times over.