Thanks for the reply, Amir. There is lots to cover here which is why I was hoping to break this down into just one question at a time.
Based on the replies I've seen so far, let me phrase it this way:
I understand and completely agree with running products through tests and you get zero argent from me about any measurements you or anyone else wishes to put products through. Where my concerns arose and the reason I reached out to to Rob was that it appears to me that the M-Scaler is being judged negatively for measurents that are objectively meaningless, specifically:
- the 1kHz tone which you stated did not benefit from upsampling
- the jitter measurement which you stated would be fixed by any decent DAC
Again, I'm not debating the measurements. My concern is there is a lot of discussion here about people being misled by audio companies while I feel that the subjective judgements of measurements that are objectively irrelevant to the real world performance of the device in question (whatever it is) is equally misleading.
Let's pretend for a moment that the M-Scaler does do what it's said to. If someone new to the hobby we're looking around for reviews and saw your comments on the 1kHz tone test (with Hugo 2) and on the jitter test, they'd likely be instantly turned away because they wouldn't necessarily understand that neither measurement matters.
So, I guess my question here is this. Are you looking to provide objective data and unbiased interpretation of that data or are you using the data to illustrate your own opinions of the products? (I am not judging either approach and not suggesting any manipulation of the data)
Finally, I want to clarify here that I reached out to Rob Watts to ask him to answer my questions about the measurements, not to read and critique your review. I also respect the fact that he makes a point of not discussing other people's reviews (regardless of their objective or subjective content). Doing so would create a very combative and potentially disrespectful tone in our hobby. So, Rob not reading the review was in no way disrespect based on what he said to me and he was also quite familiar with much of the content of your review already because it had been posted and discussed at length on Head-Fi.
(I have no need or desire to defend Rob, but will definitely call out unfounded criticism when I see it, no matter the recipient.)
You’re missing a fundamental issue that could make this discussion much simpler: to the extent some of the measurements could be said to be “meaningless,” that’s because they don’t address the M-Scaler’s claim to fix or restore transient losses by upsampling the original signal.
What you’re missing is that
@amirm ’s measurements don’t detect that feature because NO measurement can detect that feature. And the reason is that it’s impossible for upsampling to restore anything already lost when a recording was digitized at a lower sample rate.
To put it another way, it is impossible for a transient to be “too fast” for a given sample rate, EXCEPT if the transient is at a higher frequency than the sample rate can encode. And since 44.1k already can capture frequencies up to (and beyond) the limit of human hearing, there is nothing for the M-Scaler to “restore” or “reconstruct,” even if upsampling could do such a thing (which, again, it cannot).
So your argument, and as far as I can tell, that of everyone else critiquing Amir and defending Rob Watts here, boils down to, “I don’t believe that what Amir and others are saying about the basics of digital sampling theory is true - Rob Watts is smart and therefore you guys are untrustworthy, close-minded, and/or incompetent to test or evaluate his gear.”
That’s just bush-league Appeal to Authority fallacy, no matter how much you try to dress it up as some kind of nuanced set of interview questions.