Myself, I find the explanations and theories of manufacturers and just about everyone else to be at best interesting but more often than not distractions, and often misleading ones at that.
So lewm and lastperfectdaymusic, if you're looking for the typical audiophile banter as to why you can just go look elsewhere. There's reasonably likely explanations as to why this stuff works (dither) but the last thing you guys want is to have it proven. Also, seems to me, not all that interested in results either. Or you wouldn't be contesting it. You'd be reading all the threads already posted by the many people who have heard this stuff and know how effective it is.
All I can say is no lewm, I do not "think" SR PHT makes a "significant" improvement- I KNOW it does. Why, is what I do not know. WHAT however there is no doubt. It is significant.
My reviews were posted months ago. There are 4 versions of PHT. Purple Haze is indeed hazy and the only one I did not care for. Blue Velvet was okay but not worth it to me. Black Widow opened up the stage and improved dynamics and layering in a very neutral way across the board. Green Dream did the same only with an intoxicating borderline seductive liquid quality that really draws me into the music. I was able to get Betty at HighEnd-electronics.com to work with me and so now have one Green Dream and one Black Widow right on the Koetsu, with another Green Dream on the Origin Live Conqueror tone arm tube. There are also two ECT on the arm base, and one on my motor pod. The ECT are a similar effect to the Black Widow, improving dynamics and inner detail and very across the board neutral.
No one else includes these because no one else knows how to make them. The Origin Live Enabler is inexpensive, until you factor in the time it takes to install, and the hardware, the need to re-tweak everything, and the fact this winds up being a massive waste of time in the event it turns out to not be all that great. Let's face it, for $25 almost nobody is gonna go to all that trouble and then turn around and remove it, unless it actually makes things worse. PHT on the other hand can be installed and moved around wherever you want or removed literally in seconds.
Practical results and considerations. Or theoretical gobbledygook. Choose wisely.