Stupid Question : when I buy a high-res album, e.g. from Qobuz, e.g. Moving Pictures by Rush at 192 KHz / 24 bit, where does this high-res file originate? Did somebody re-digitize the old analog masters at a higher resolution? Presumably it’s not that somebody upsampled a 44.1/16 CD and did some kind of interpolation. Sorry if naive Q
It’s usually re-digitized as you describe.
It is possible to double check (you can look for high frequency content over 22k).
I believe there have been cases (probably not on Qobuz) where things were just upsampled - but as you’d expect this didn’t go down well with the customers.
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The reality is there’s no way to know unless the provenance is provided by the record company. In the past, many high-res files were found to be 16/44 transfers with no additional music above the redbook standard.
in contrast Signals sold to me as 96 KHz looks like it actually has some nonzero info above the nyquist of 44.1 Khz (i.e. 22.05 KHz) … is it real? is it noise?
As you say - assuming the tool is working correctly - that isn’t good - clear signs of a brick wall filter at 20k!
Still not great.
Might’ve be remastered from a 44k transfer or similar. So some content greater than 22k, but not the smooth roll off you’d expect from analogue.
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That looks fine.
I usually record at 96k, and there isn’t a usually huge amount up there - but have seen cymbals etc up to 40k.
So it’s more interesting than I noticed. Some things still look limited - but with modern music it could be they were using samples, or samplers that were 48k limited on some tracks.
But as a whole it still looks legit.
That looks like it might be a modern 96k recording.
100% right!
van halen 1984 sold to me as 192 KHz at least seems like a smooth rolloff even if there’s nothing much up near the nyquist
Questionable: Julien Baker/Torres sold to me as 96 KHz ; looks like a brick wall at the nyquist for 44.1 KHz
I mean, at least the high-res Qobuz are cheap right now, as a subscriber I get these discounts… even cheaper than the 44.1KHz/16bit versions sometimes.
You are doing all the right things and getting the right answers using Spek. Sometimes you aren’t getting what you pay for, and Spek is a great way to fight back and keep vendors on their toes. I’ve used it to get refunds in the past.
BTW Audirvana has a feature built in to highlight “fake” high-res files using Spek-like analysis.
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It probably won’t change your mind, but someone has to point out that you can’t hear anything above 20kHz or so, so it doesn’t really matter if there’s anything there, signal or noise. (As a matter of fact, it’s better not to have anything there.) The quest for “genuine” hi-res is quixotic. If you think your DAC works better with 96kHz or 192kHz or whatever sampling above 44.1kHz, you can upsample during playback.
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192 kHz refers to the sample rate, not the audible frequency. We can’t hear above 20 kHz when we’re youngsters, let alone later in life.
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Moving pictures was recorded digitally at 16/44.1 I believe. It might have been remastered higher for purposes of accuracy with mastering plug-ins.
And more dough for labels that engage in a tiered, pay-per-resolution scheme.