The second step in achieving true high-resolution audio playback is to acquire discs or files that are actually high-resolution. This seems like it should be simple, right? You go to Amazon or one of the high-res download sites, select a product that says “High-Resolution” somewhere in the marketing materials and presto, you’re good!
Sadly, no. There is no HRA police or even definitive list anywhere. There is a site called “Find HD Music” but they simply list all of the albums that are being made on the high-resolution digital music download sites. Qobuz, Promates, Ponomusic, HDTracks, ProStudioMasters, SuperHiRez, and HighResMusic and all of the others get most of their content from the big labels, small labels, or digital music aggregators. The Omni Music guys in the UK are the suppliers of all of the audio tracks that are going to be sold on Ponomusic, for example. And they are delivering standard CD rips and Pono is pitching them as high-resolution.
Do we have to trust that the retailers are really giving us true high-resolution audio? Actually we don’t. I’ve analyzed plenty of high-resolution audio files (including the recent downloads from Promates in high-rate PCM and 88.2) and posted lots of audio spectra on this site.
The German site HighResAudio even has a whole page dedicated to their guarantee titled High Resolution Audio – Fake or Not. You can read it in English here.
First, it’s important to realize that HighResAudio is a digital download store that has license agreements with the major labels. That means that the files they receive are coming from the catalogs of the majors as their mastering studios make their way through the analog tapes that are likely to sell to “high-resolution” customers. Knowing that, we know that the files are coming from standard definition sources…i.e. analog tapes. They are the best versions of those tapes but I have staunchly maintained from 2000 that they are only as good as the sources. And the sources are not high-resolution, unless you consider third generation analog tape as HD. I don’t.
The HighResAudio site description of high-resolution audio starts out on a confusing note:
“True, native High Resolution Audio Format means that during recording, the fine structures contained in the music signal are adequately resolved per unit of time. A true music signal recorded with microphones contains sensitive temporal information in the 45-50 kHz frequency range. For certain instruments (for example, trumpet with straight mute) and above all for percussive sounds, this range can be higher. The transfer of fine information is not possible with equipment which uses 22 kHz frequency bandwidth (CD) or 24 kHz bandwidth (the industry and radio standard).”
We’ve been talking about the relationship between frequency and time over the past few weeks. They are intimately related in digital audio systems but to say that there are “fine structures contained in the music signal” that can only be captured and reproduced using high-resolution is reaching a bit. If they’re referring to the ultrasonic frequencies as the “fine structures”, then it’s true that using a sample rate of at least 88.2 is required. But what about the “fine structures” associated with dynamics? Or the fact that most recording systems prior to high rate PCM didn’t record those frequencies.
Got to run…stay tuned.
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