With respect to the ad copy for that mod, one of the "DIY individuals who operate(s) on misguided notions" is Tyll Hertsens, founder of Headroom, headphone guy for InnerFidelity, and a guy who has actually spent a lot of time working up a reliable system for headphone measurement and publishing his results - the type of graphs which seem conspicuous in their absence in the aforementioned copy. IIRC the originator of the Anax mod published quite a bit of frequency response data as he developed his mods too. If this is better I would love to hear it, but there doesn't seem to be much info on that page to help motivate the buyer. Perhaps we are too misguided to understand the rationale behind the mods?
Yeah marketing speak is an instant 'red flag' for me as well. And their 'marketing outreach' is a bit 'thin'. But then I'd rather have it that way, that its opposite.
And I know Tyll personally, and he provided the motivation (ie. pushed me) to explore this whole avenue of investigation. I have installed the 'anax' mods (as in several versions of them) and they all had their strengths and weaknesses, but they were (relatively) easy to remove and try another version.
But this SAA mod is much more 'permanent', so it is a 'risk' in that if you don't like the results there is much more involved in going back to stock.
And this SAA mod does WAY more than than any version of the anax mods. At least in terms of audible results. When coupled with 'proper' upstream equipment and source material, the results can be astounding.
And I wish to meet with you and heartily thank you for your efforts as well. Between the HD-800 mods, and a few others I have made, I also purchased 2 of your power cable kits. I then proceeded to 'mod' them, heavily. The results, in my system, are astounding as well. The system I now have is the culmination of decades of investigation and exploring a variety of 'key' factors, which all coalesced into what I currently enjoy. And this SAA HD-800 mod is an indispensable part of my system, as well as what your power cables (now in generation-4) revealed to me. Such that they still are a point of reference in my system.
As for the lack of measurements, we are working on that.
And I'm sure that everyone is aware that there are very few folks who are capable of performing measurements on headphones and related gear. So in this regard it doesn't surprise me that there is a lack of measurements.
Tyll is a pioneer and we are lucky he had the foresight to not just see the need for these measurements, but also that he made it happen.
JJ