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Misleading Measurements


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@bluesman I like the way you approach finding answers. You pick up your guitar, record it, and make your points. Using different tools, I often take a similar approach.

 

I have said for years, I'm an open-minded skeptic (similar to the Sagan quote above). So, a bit of the friendly skeptic part: I don't (yet!) see evidence of sum and difference frequencies that you mention, other than the linear effect of beats. Your recording doesn't help me (yet). Can you help me? I'd like to work through this with you to understand the sum and difference vs. IMD issues.

 

Some comments on your recording:
- I don't like the Spectrum function in Audacity (which I otherwise love), so I use my own.
- I don't find any "notes" (frequencies) near 246Hz
- I find 2 peaks at about ~221+ and ~226+Hz, giving the noticeable ~5Hz beats. I looked at the 2nd, 3rd and 4th harmonics: they are there, but I don't see anything at (F1 + F2) frequencies.
- There is not any signal near 5Hz (F2-F1)
- There's a lot of "stuff" between 20-34Hz, with a peak at 26+Hz. I have no idea about the origin.
- "Something" changes at about 1.0s. It is audible and visible as a sudden amplitude drop. Any ideas? Could you have adjusted your hand, or...?
- All the "stuff" around 26Hz is gone after 1.5s
 

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3 minutes ago, pkane2001 said:

But I already mentioned the ASR thread on testing and validating of DISTORT while it was being developed (still is, really) easy to look up and find what testing was done and what results were produced by me and by others. 

Hi Paul,

I understand, have seen the other thread, and will have some questions for you there.

But here, keep in mind you and @Audiophile Neuroscience are stuck in the same place I am with my cousin. I'm waiting for her to reach out to me, and she is doing the same in reverse. You want AN to put in some effort (define, read/search, try out), while he is waiting for you to put in effort to provide evidence of validation. It won't work. Either one of you has to flinch first (I won't hold my breath) or others will need to jump in. I attempted above.

Cheers, SAM

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2 hours ago, pkane2001 said:

Welcome to the loop (get out while you still can :))!

Hi Paul,

 

I understand your perspective, and given the complexities of online relationships, I don't wish to convince you of anything

 I've interacted a few times with AN also, even before "the big break", sometimes very satisfyingly. He does have a few issues upon which he chomps down like a pit bull and won't let go - even if you turn the hose on him. Like validation. If it is done in good faith, he reminds me of a couple of reviewers I've dealt with a few times. They have issues they chomp down on, but even after a bit of swearing and name-calling during the rewrite/resubmit phase, I have to admit that the final product (the paper) was better after dealing with the "issues".

In this thread, the question of good faith arrises, and I hope giving the benefit of the doubt is warranted.


SAM

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5 minutes ago, bluesman said:

 What we still don't know is what else it may be doing to the signal passing through it.  That is not an unreasonable thing to want to know.

 

 

[snip]

 

 

So, specifically, what I'd like to see is a list of the other effects on the source signal that were considered possible and shown not to occur with use of the app in question.  This is a very reasonable thing to ask - it's neither pejorative nor argumentative.  It's just a factual inquiry that deserves an answer.  Since I didn't get one and I want to try the app myself, I'll try to determine the answer myself.  And I promise to try hard to avoid misleading measurements.

I guess you didn’t see post#776. If you answer mine, I’ll answer yours.

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2 hours ago, 992Sam said:

 

look man, I know what I saw.... just go find the PS Audio DirectStream DAC review thread and you'll find at least 3 banned users.. all of them dared try to defend the DAC they felt sounded good against the measurement nazis in that thread including Amir.   I saw the same all over the board while lurking... 

hey man, @danadam wasn't calling you a liar... he just asked for examples. Some people, like me, don't automatically believe everything they read on the internet, especially interpretations of "what happened". It's nice to interpret for oneself.

 

Disclaimer:I don't know how to be a good moderator for internet forums. I notice on several forums, including this one, that some people are banned quickly after what I would consider minor infractions (although there could be a backstory I don't know), while other repeat-rule-violators are tolerated.

 

That said, I went to look at the PS Audio DAC thread, as you suggested. I found:
- With over 1500 posts, I wasn't willing to look at all of them. I perused here and there (beginning, middle, end of thread) and didn't see anyone labelled "Banned", but I found 2 users who were banned.
- One was a "Major Contributor" with over 4000 posts who seemed to be banned around February. I could not figure out why he was banned, but it was clear he was a fan of measurements, but also sometimes a bit abrasive.
- The other was you. You know why, and the reason you were banned was *not* an unwillingness to toe the pro-measurement line. People here have been banned for the same reason you were banned there.

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2 minutes ago, The Computer Audiophile said:

Examples please. 

I'm not going to start an open fight with you. I'll PM you a couple examples, and you are free to post them. As you know, or can check, I've praised your moderation (but included some bafflement). Also, read my disclaimer.

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It might help to not spend too much effort understandIng AES17-1998 given the Forward of AES17-2015 states:

Quote

This document substantially revises and updates AES17-1998

and the Forward of AES17-2020 states:

Quote

This document clarifies the definition of levels, the units FS and dBFS.

I don't have the new document (nearly twice as long as the 1998 standard), but perhaps all is made clear!?

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