wgscott
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- Mar 1, 2016
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One fine day, early on in my attempts to acquire and appreciate high-resolution downloads, a senior colleague, who listens mostly to jazz that he acquired on vinyl many years ago, came for a visit. Since I don't know anything about jazz, he suggested a few titles, and a subset of them were available from HDtracks.com, so I purchased and downloaded them for his visit. He would never call himself an audiophile, but I wanted to impress him with what computer audio could do, relative to mp3 or CD playback. He is a scientist (and member of the National Academy) and a very talented amateur musician as well.
The first title I played for him was one called "Lush Life" by John Coltrane. Since I know nothing about jazz, I guessed from the title that it must be some sort of ballad about being an alcoholic. But it actually sounded pretty good to my ears, and I didn't even feel a need to run out an purchase a white polyester leisure suit.
So after it was done, I asked him what he thought. He was very polite, but eventually said he thought it wasn't as good as the CD, and inferior to the initial pressing. I then told him it wasn't an mp3, and that it was, in fact, "high resolution." I explained to him what that meant, and got the predictable response, but in addition, he suggested I do a Fourier transform on it to see what was going on. (We both do X-ray crystallography, so this isn't an unnatural suggestion.) I found some GPL software called Audacity on line and downloaded and installed it, and proceeded to show him what the file looked like. To my surprise, here is what it looked like:
The larger image shows the Fourier of the left and right channel to 48kHz, which is the upper limit imposed by Nyquist for 96kHz sampling in the case of this high resolution file. Both this and the accompanying inset (which you can think of as a cross-section of one of the channels) show that there is very little information beyond about 22 kHz, which is the frequency limit imposed on CDs and mp3s. In other words, there was no significant high resolution information present in the file.
One could object that this is irrelevant, simply because even a child's hearing won't go above 20kHz, but that is only part of the story. The reason you might want to have higher-frequency information present is to avoid having a brick-wall cutoff imposed at ~22kHz, which can produce audible aliasing artifacts and Fourier truncation artifacts, among other problems. Besides, I paid a premium for those files, above and beyond the cost of a CD, to have that higher-frequency data present, even if only my dog can appreciate it.
I complained to the vendor, as did apparently a number of others, and they pulled the title and offered me another download for free, so at least they tried to make it right after the fact. I very much appreciate that.
The problem is that this kind of thing happens fairly frequently, and is not limited to any single vendor. I've even encountered it on some of Neil Young's stuff. (I presume a vocal advocate of high res music wouldn't knowingly do that.)
Here's a few other highlights I have found (to pick from about 30 examples I have personally experienced). This is common enough that I hesitate to purchase high–res music now, without seeing the data.
That last one is particularly weird.
The first title I played for him was one called "Lush Life" by John Coltrane. Since I know nothing about jazz, I guessed from the title that it must be some sort of ballad about being an alcoholic. But it actually sounded pretty good to my ears, and I didn't even feel a need to run out an purchase a white polyester leisure suit.
So after it was done, I asked him what he thought. He was very polite, but eventually said he thought it wasn't as good as the CD, and inferior to the initial pressing. I then told him it wasn't an mp3, and that it was, in fact, "high resolution." I explained to him what that meant, and got the predictable response, but in addition, he suggested I do a Fourier transform on it to see what was going on. (We both do X-ray crystallography, so this isn't an unnatural suggestion.) I found some GPL software called Audacity on line and downloaded and installed it, and proceeded to show him what the file looked like. To my surprise, here is what it looked like:
The larger image shows the Fourier of the left and right channel to 48kHz, which is the upper limit imposed by Nyquist for 96kHz sampling in the case of this high resolution file. Both this and the accompanying inset (which you can think of as a cross-section of one of the channels) show that there is very little information beyond about 22 kHz, which is the frequency limit imposed on CDs and mp3s. In other words, there was no significant high resolution information present in the file.
One could object that this is irrelevant, simply because even a child's hearing won't go above 20kHz, but that is only part of the story. The reason you might want to have higher-frequency information present is to avoid having a brick-wall cutoff imposed at ~22kHz, which can produce audible aliasing artifacts and Fourier truncation artifacts, among other problems. Besides, I paid a premium for those files, above and beyond the cost of a CD, to have that higher-frequency data present, even if only my dog can appreciate it.
I complained to the vendor, as did apparently a number of others, and they pulled the title and offered me another download for free, so at least they tried to make it right after the fact. I very much appreciate that.
The problem is that this kind of thing happens fairly frequently, and is not limited to any single vendor. I've even encountered it on some of Neil Young's stuff. (I presume a vocal advocate of high res music wouldn't knowingly do that.)
Here's a few other highlights I have found (to pick from about 30 examples I have personally experienced). This is common enough that I hesitate to purchase high–res music now, without seeing the data.
That last one is particularly weird.
. So yes, let's create a new thread. I will try to get one of the videos created so that you see what I am trying to highlight there that is harder to do with static images. One of the things I also like to do is a bit of a tutorial as I don't think most people know how to read the spectrograms.
