Having just read this entire thread, it's easy to see the utter absurdity of the suggested tweaks (except for the most rabid believer) and the people who sell such crap are either conmen or delusional themselves.

However, other than being further (much further) out on the spectrum of the objectivist/subjectivist debate, is there anything ultimately different about this compared to the claims made about cables, burn in discs, vibration control devices, cd pens, amp shelves, pucks, isolation feet, clarifiers, electromagetic stabilizers, and so on?

How many companies sell speaker cables, power cords and/or interconnects for thousands of dollars, with a straight face? Lets face it, for better or worse, hifi audio product marketing is designed to simply separate people from their disposable money. The question is whether it is fraud or not.

Is there any difference between psychoacoustics and a scientifically measurable process if both result in a perceived improvement in sound? On the one hand, I can easily conclude that anything that is only psychoacoustics and unmeasurable by any known scientific method is fraud and anything that is measurable and independently verifiable not. On the other hand, if you hear a difference and believe you are getting the promised result, why aren't you? If you are absolutely sure you are getting what you paid for, is there fraud?

In other words, if it sounds better to you, who's in a position to tell you it doesn't, you've been defrauded and you are a fool?

Oh, and what about the "wow" factor for something that is very expensive, looks beautifully designed and made with expensive component parts, that ultimately is a true work of art and in many instances is a large component of the cost. If it looks so good and sounds good to you, where does that lie in the debate?

In general, fraud lies in the intent of the one promoting the product. However, in the high fidelity world, with consumers believing what they hear, you'd be hard pressed to prove it. Compared to snake oil medicine, where sick people can die by taking it either because it's toxic and/or by not pursuing medically valid treatments, not many people are going to complain, especially if they think they got what they paid for.