Thanks for the nice explanation. I will comment on this part:
I am trying to think in all the high-res samples I have examined whether any of them have usable content beyond 48 kHz. As such, it is perfectly proper to throw away the spectrum above that. And then, in the interest of maintaining any characteristics that the original 192 kHz sampling provided, to upsample back out.
So in the context of perceptually preserving high-resolution content, what they do is valid.
It is only an issue if they had claimed mathematically lossless which MQA is not.
I ask again: why would we, as the objectivist group, get up in arms over the content above 48 kHz getting thrown out? Why would we be bothered that all the junk above that spectrum is discarded?
It is as if we want to wear the hat of subjectivism while using objectivism to critique it.
Amir, I don't disagree with the individual statements here, but the way you have put them together does not make sense to me.
Throwing out content above 48kHz, aka downsampling from 192kHz to 96kHz: I agree with you - there's no need for those ultrasonic frequencies. But then the question is, once the samples are discarded, what possible "characteristics that the original 192kHz sampling provided" could there be - in other words, once you've downsampled from 192 to 96, what on earth is the point of re-upsampling to 192? What "perceptual" preservation are you talking about? The only "preservation" of 192k that MQA provides, is the color of the little LED light on MQA DACs, and a "192k" readout for musical streams that in actuality are only 96k. To me that reads like marketing and fraud rather than "perceptual preservation."
The point here is that it is not
me (and others critical of MQA) who is saying that a 192k sample rate is worthwhile - it is
MQA that is saying that. Without the underlying idea that 24/192k resolution is important, MQA becomes pointless.
In other words, MQA files are, as far as I know, a little larger than 16-bit, 96kHz FLAC files and a little smaller than 24/96 FLAC files, on average. If that's the case, then why not just go with 24/48 or 24/96 FLAC files? The bandwidth/streaming requirements would be more or less the same.
In that case, the only remaining argument for MQA is that their files sound better than 24/48 or 24/96 FLAC because they "correct" for the sonic signatures of the ADCs used in the recording process, and for the specific characteristics of the DAC used during playback. The former claim makes sense only when the ADC is known
and when it's not a modern, multitrack recording that uses multiple ADCs, multiple A-D-A-D steps (as in the very common rock mastering practice of re-amplifying/re-recording certain tracks in a multitracks). And the latter claim has been shown to be largely BS, as MQA DACs using a variety of DAC chips, from variety of manufacturers, all have the same small number of filters applied during the final unfold - meaning the filters are not "customized" but instead merely reflect Stuart/MQA's
subjective preference for minimum-phase, apodizing filters.