Real scientists write a lot of things like "some of the evidence suggests..
Which means???
Lets get down to brass tacks. When they "use" that sort of scientific MUMBO JUMBO to sell products that DON"T work, it pisses me off. You know as well as I do that RPG products are all over the net.
Even though we've been through this subject a few times, I'm going to say this again for the benifit of any newbies that are currently visiting here. I'm certainly no expert on these subjects. And thats why I started asking questions regarding "diffusion" on this very bbs four years ago. I had purchased Alton Everests book called the Master Handbook of Acoustics in the early 90's. Now, I don't know about you, but when I read something that claims to be a so called "Master", I USED to assume they knew what they were talking about, and had the credentials to back it up. And indeed, within the book it appeared to do just that.
I don't know if any of you have this book, but I had the second edition, which had a chapter on Diffusion, and illustrated the current "scientific"concepts, techniques and products in vogue at the time. But when I say in "vogue", according to the book, these were based on solid scientific investigation and testing ie...Shroeder tests.
At the time, I was amazed at the "scientific explanation" and pictures of QRD's and Prime Root diffusers shown in the chapter on Diffusion. For years I planned on building some of these in my own home studio. But as you know, things don't always go as planned. As time went on, I found this bbs and at some point asked about how to interpret the "quadratic residue sequence". Also at this time, the bbs resident expert(John Sayers, who is a pro studio designer) replied right back. He suggested in no uncertain terms that he "had seen MILES of these type diffusers torn out of current studios because they PLAIN DON"T WORK!!
Well, as you can imagine...my bubble had just been burst!!
And I was PISSED!! After all, how can a so called "acoustician" with credentials write and sell a book, with suggestions of approval of products such as RPG sells, with scientific mumbo jumbo explainations on WHY and HOW they work, and THEN have professionals in the working world say they DON'T. Needless to say this led me on a quest to find out what the fuck was going on. Frankly, I don't think this quest has ended yet, as the link I posted clearly illustrates this quagmire STILL exists!
Two years ago I found a yahoo "Acoustics" group which has since been YANKED off the net
because of circumstances that were pretty wierd if not downright unlawfull . These circumstances appeared to have EXACTLY to do with what I'm talking about, and to this very day, as you put it Apl, "evidence suggests" that there are people out there that don't want certain knowlege known as it may cause ....well, lets just say...unpleasant consequences to some people and companys
Ethan, you KNOW exactly what I'm talking about here. Let me go on.
At that time I posed some questions to the "resident experts" on this very subject, of which I recieved some startling replys, which in effect didn't really answer my questions, but posed some even deeper questions regarding small room acoustical behavior. Thats when I began my acoustics "Alice in Wonderland" journey into the acoustics rabbit hole. I barely made it out alive
But not before seeing how deep and sometimes sinister it may be...
http://forum.studiotips.com/viewtopic.php?t=2196
, and how wierd it can be. To this day I am amazed at the heretofore unaccessable information that has surfaced for acoustical laymans consumption.
As time and questions/answers came and went, I began to smell something funny. It was at this point I discovered another Yahoo group called Alt. Physics, which I began to visit frequently. I soon discoverd most of the members of the Yahoo acoustics group had migrated to, as it was the only other viable "scientific" net community out there at the time. But as you probably are aware, group and audio/studio forum formation on the net has exploded. It was there that I finally posed a question directly conceived to expose what and what not is known about "diffusion". I posted this heading...
SMALL ROOM DIFFUSION-FACT OR FICTION?
I explained what I said above about the "Master Handbook" and asked about building some of those devices in the pictures. Well, it took at least a week before some serious, if not vague answers began to appear. In fact, it was beginning to look like a dance whereby "professional curteousy" superceded scientific FACT, as no one dared to actually come right out and tell me YES or NO, to the question...DO QRD"S WORK...PERIOD. And if NOT, why don't these companys that sell them get SUED! And if they do indeed work, why do I hear other acoustic professionals tell me they DON"T!
Regardless of your personal opinion of whether these concepts work or not, I still feel to a certain extent that the Emporer is walking around nude, and when those proponents of TRUTH try to expose this and other acoustical quagmires, they are COMPLETELY shut down on some of these forums. Here is an example..
http://forum.studiotips.com/viewtopic.php?t=2190
http://forum.studiotips.com/viewtopic.php?t=2191
And frankly, I don't even give a fuck anymore cause I'm at the point where I'm ready to chuck this hobby for good. But its nice to know I'm not the only one who chases these curiosities.
http://forum.studiotips.com/viewtopic.php?t=2154
Ok, I'll be the first to admit, I'm certainly no expert. In fact, I'm still just a somewhat enlightened Home Recording enthusiast wannabe, but that doesn't mean I can't smell snakeoil. And if someone can prove its NOT, I'm all ears, but as far as I can see, theres some pretty strange stuff goin on out there. And I ain't talken about egos either. I'm talken DOLLARS AND CENTS.
Quite a discussion though. Although I already went through one on that site last year about the same thing. I wanted to build a QRD on my ceiling like some pictures in Everests book. I was told by members there that they were bullshit. Which is why I've been pissed at "acousticians" ever since. I mean, I paid almost $25 for that book in the early 90's, and believed everything in it., Basically I was told by an acoustician who frequents Studiotips site, that Everests book was .....well, I better not say. 
I don't believe THEY are JUST "net" acousticians. Thats not to say that the others you have mentioned are on another planet either. I'm just saying, it amuses me when something embraced by "science" can be so easily rejected by the proponents of "other" schools of thought. I was taught either that "scientific PROOF" EXISTS or it DOESN"T...period. 
Oh well, such is life.