Jon Risch distortion test signal

[ToddB]

This is going to read as if I'm replying to Jon, but it applies to the thread in general.

Yes, let's keep this on topic. If there are other issues that people would like to discuss, please start other threads about them.

Also, I think all of us (myself included) can probably tone down the personal invective. For the most part, I think this exchange has gone amazingly well, and it's been very interesting and informative, and I for one would really like to keep it that way.

I don't have any particular technical knowledge or experience related to this subject, so take my opinion for what it's worth, but based on the arguments given in this thread, I'm not seeing a sufficient rationale for taking the position that Jon's test method is without merit. The argument that his new method somehow suggests that the previous methods are wrong seems to be particularly flawed, since scientific advancement historically doesn't seem to be so much about disproving previous understanding, as it is about providing more clarification and refinement of previous understanding. Unless one holds the position that the current methods and abilities of distortion measurement are inclusive of all relevant aspects, and will forever continue to be so, then I think common sense suggests that methods of acquiring more data would be beneficial, IF that data can prove to bear out some experiential corellation, as Jon suggests his method indeed does.

Also, and perhaps this is more significant, nobody seems to be disputing the validity of the actual test method itself, nor the figures Jon claims to have generated by using it. And I don't believe that anybody said a thing about Jon's claim that using his method enabled him to discover problems with the digital filters in some of the CD players he tested. That purpose alone would seem to be an eminently useful aspect of his method, even if it's potential elsewhere remains in dispute.

I think someone asked if I was "pretending"(?) about wanting people's opinions about this subject. I was not. What piqued my interest in this was reading a review of some Simaudio component, and the reviewer stated that the product literature mentioned that Simaudio try to eliminate IM from their products, because they think it's more detrimental to sound quality than HD. Jon has a test method for measuring these that's different than any I'd read about anywhere else, so, here we are.

Jon, I'd appreciate it if you could elaborate on what you meant about the "past signal history" portion of this statement:

The data is out there, audio amps, and other audio devices have HD and IM that vary with level, with frequency, even vary with the past signal history of the device!!!

That's a new one for me.