You could have a thousand people saying their car runs faster when they wash it. It doesn't matter. The truth in that is measuring that it did or did not. Chefs make their food plates attractive. Many people as a result think the food tastes better while we know that can't possibly be true. Our mouth has no eye. The brain does of course.
By the way, it is not a matter of being skeptical. It is a matter of analyzing what is there and realizing it doesn't do anything. I am not a fan of skeptics. I am a fan of calming looking at something, analyzing it and having that be the reference point of view as opposed to what masses may be saying.
To that end, those of you who have the unit try to imagine that it has made the sound worse. Think hard to see if the improvements you thought were there, were not. Do this as honest as you can be with yourself. Then see if the improvements are resilient.
Consider that if a simple device like this made a difference, real circuit changes in our electronics would have effects that would be so large as to make our measurements blow off the scale!
These are the types of logical analysis that you want to do rather than going by how many people thought it made a difference.