I travel each fall to Denver, Colorado to attend, present and/or exhibit at the Rocky Mountain Audio Festival. Last year, AIX Records and iTrax.com demonstrated HD surround music in a couple of rooms, but overall the time and money spent didn't really pan out for our little company. The show is one of the last bastions of audio focused conferences (although there is a new one called the AXPONA happening in Florida in the spring - check out axpona.com for more information) but the RMAF is decidedly a two-channel, vinyl, tube, traditional audio weekend. So this year, rather than stand in a room hawking our wares and trying to sell audiophiles on the advantages of HD surround digital music, I did a lot more hiking with my wife and sister in the local mountains and dedicated a single day to the RMAF 2009.

I was very gratified to be invited by Majorie Stiefel and her advisors to give a presentation on Sunday afternoon, which I entitled, " High-Def, Surround Music Recording, Reproduction & Distribution."  The title morphed into "Myth Busters: HD Music" as I explored the world of HD audio and the falsehoods perpetuated by a number of venders/labels in this space.  It irks me to no end to spend so much of my time and resources producing uncompromised HD recordings only to find that many other companies promote their tracks as "HD" even though they derive from standard definition sources. If you've followed my articles or blog, you know this is not new territory to me. What is new this time is the support of a rigorous set of tests that I performed on a variety of tracks from lots of different sources. I ran spectragraphic analyses on about a dozen tracks from most of the major online "HD" distribution sites as well as "HD" files distributed on DVD-Rs. The results were not really surprising…many of the tracks that are so highly regarded simply do not contain the requisite frequency response or dynamic range that their specifications make available.

It started about a year before when I received a handout during the CEA high performance audio board meeting in Las Vegas. Ray Kimber, a good friend and the producer of some marvelous recordings, gave me a printout that showed a couple of spectragrams of one of his products. One was of a traditional CD resolution track and the other was of one of his DSD recordings, which he released on SACD. It was immediately clear that the CD had limited frequency response…at least compared to the DSD spectragram, and by a very large measure.

If you don't know what a spectragram is, let me briefly explain. The graph plots time along the x-axis, frequency range along the y-axis and the intensity or amplitude of the tracks frequency content through a range of colors (red being quite high in amplitude and blue/purple representing very low amplitudes). As you would expect, music tracks have a lot of reds, oranges and yellows in the low to medium frequency ranges and then the amplitude tapers off as you eclipse around 10-15 kHz. There is still sound up around the highest registers. I've got spectragrams of Wallace Roney playing a trumpet with a harmon mute inserted and he's generating frequencies the plow right through 48 kHz! I will not enter into any arguments on whether these frequencies are meaningful to audio playback…I'm not alone in believing that they do, especially over an extended listening session. But the graphs clearly show the presence (or absence) of music/noise content about 20 kHz.

So when I looked carefully at the graphs that Ray had handed out, I noticed that the DSD track had a very visible red "haze" hovering out there around 35 kHz. The oft maligned "noise shaping" artifacts were clearly visible and showed up with substantial energy. Does this noise affect the final playback sound of an SACD. You bet it does, if it is allowed to pass through to the final encoded and mastered disc. Thankfully, the mastering process removes this HF noise and the final product presents only those frequencies in the low to mid 20 kHz range. SACDs are better than CDs in this regard but not by much. This "red or purple haze" intrigued me so I decided to become a registered member at all of the HD download sites and acquire copies of all of the HD DVD-R files that circulate among audiophiles and test them using spectragrams.

The results were very telling. Can you imagine my surprise to find that the so-called HD downloaded files from one company are actually upconverted analog recordings? There was no difference between the CD original and the same audio plopped in a 96 kHz/24-bit bucket. And there's no way to tell from looking at the offering on the site. One site actually brags about the "HD 96/24 upconverted" downloads that it sells, ignoring the fact that there is no new information added during the upconversion process. The source recording at standard definition is all that can be reproduced. Perhaps the worst offense was the two "different" resolutions that were available from one site. You are asked to pay more money for the 176.4/192 kHz version than the 88.2/96 kHz version…when in fact the two files are sample for sample identical! Audiophiles seem to shop by the numbers rather than with their ears.

There are several companies that are distributing their tracks on DVD-R discs because the files are so large that making downloads out of them is impractical. I have analyzed a number of these files as well and am sorry to say that there is nothing above 35 kHz in any of them. Why bother with 176.4 samples per second when the resultant audio doesn't take advantage of the higher sample rate? It's true that higher sample rates also contribute to easier filtering in the D to A process. But why wouldn't the HF material that is produced by the instruments show up in these tracks? You'll have to decide for yourself the motivations of these other labels.

The point in my presentation at the RMAF 2009 seminar was to demonstrate that "HD" audio tracks can be analyzed to determine the degree of HF material and the dynamic range contained within them. If a track is truly recorded as an HD track, there will be information above that available on a CD. Sadly, it seems marketing has crept in to the world of HD downloads and disc based distribution. It is still buyer beware in the arena of HD audio.

That's the reason that I personally verify the "provenance" of every track available on iTrax.com. This is the only site that is exclusively providing real HD downloads.

The tracks that I record for AIX Records do contain frequencies above 20 kHz. In fact, most spectragrams extend well above 35-40 kHz! I believe that's why Dennis Burger of Home Entertainment magazine stated, "Longtime readers should already be well aware of my undying love for AIX Records. The company's award-winning, multi-disc DVD-Audio/Video releases continue to be without question, the most pristine recordings these ears have every heard."