We can thank Apple for many things, but ultimately one of their greatest achievements has been truly creating a world full of more music enthusiasts. The ability to have one's entire music collection in your pocket, was not something planned or expected at the time, and while not responsible for its invention, Apple certainly can take the credit for making that happen.

That was 2001. 'Click-wheel' through to 2014 and it's hardly surprising that the portable music platform has evolved in a multitude of ways. The world embraced the compression and portability of music, but as internet bandwidth became faster and cheaper, storage devices got larger and similarly, cheaper, and advocates emerged lobbying against compression and the "loudness wars". Neil Young himself even threw his weight (and money) behind the development of a super-format, Pono, that we're actually still yet to see launch.

Chesky Records is a name well associated with quality records and has been enjoyed by music lovers and audiophiles for many years now. David Chesky looked deep into his crystal ball and co-founded HD Tracks, arguably one of the most widely known online stores for not only his own label's releases, but also many other label's offerings thanks to some obviously clever brokerage.

The HD Tracks offerings themself have been the subject of intense scrutiny by music and recording professionals, as well as audiophiles across blog, web and forums posts in recent times. Not to single HD Tracks out however, as sites are emerging daily offering 'high resolution' or 'studio master' transfers for purchase and download.

So what's the problem?

Platforms, formats and actual resolution itself varies across recording studios, but in nearly all cases the original analogue recording is what is considered to be the 'studio master', with the exception of modern studios and recordings of course. The "studio masters" term is enabling labels worldwide to dig up these analogue masters and re-release them all over again, but some of these 'transfers' could be considered simply upsampled transcodes at best. The dynamic range is limited to around 10-12 bits and the frequency response extends to around 20 kHz. It is the studio master, but this is often transferred from other analogue masters. The original 24-track is mixed to the 2-track master, and then transferred again after mastering…at each phase it loses 6 dB of signal to noise ratio. 'Analogue tape' is standard definition - not high definition.

The problem is that there is no 'standard' or even industry-wide accepted rules that govern these transfers and releases.

One well respected expert on this matter, is Mark Waldrep, Ph.D (a.k.a Dr. AIX). Waldrep has over 40 years experience as a recording and mastering engineer, is the founder and director of AIX Media Group, AIX Records and iTrax.com (the first high-resolution audio download site launched in 2007). Waldrep also holds multiple advanced degrees in music, art and computer science. So you see, he's qualified; and passionate about this topic.

If you're not familiar with Dr. AIX, I urge you to subscribe to his newsletter here.

When StereoNET spoke to Waldrep on this matter, he stated "Over the course of 14 years or so, I've talked about high-resolution terminology and definitions with hundreds of people from audio engineers, to audiophiles and individuals from the consumer electronics companies. Thus far, I've been unable to get a consensus even among professional audio engineers. Unlike the working groups that found common ground on defining the various formats in video delivery (standard definition, high-definition and now ultra high-definition), music and audio engineers and other interested parties have not been able to establish meaningful and absolute definitions. This is a problem.

Just because something is delivered in a 384 kHz/32-bit data bucket doesn't mean that it meets the potential of a PCM recording of those specifications."

Waldrep proposes there should be three quality designations, and within them categories for both source and delivery formats and specifications:

• High-Definition or High-Resolution - Recording and playback systems that have the potential to meet or exceed the capabilities of natural human hearing. New recordings done at 96 kHz/24-bits or better with the intent to maximise fidelity.
• Standard-Definition or Standard Resolution - Recording and playback systems that have the potential to capture and reproduce a frequency range of 20 kHz and 60-90 dB of signal to noise ratio. Think analogue tape, vinyl LPs and compact discs.
• Low-Definition or Low Resolution - Recording and playback systems that have the potential to capture and reproduce a frequency range of 15-18 kHz and 20-40 dB of signal to noise ratio. Here we’ll have 128 kbps MP3, HD-Radio, AAC and other heavily compressed (data compression) formats.

"We have to maintain the distinction between the potential fidelity of the source and the potential of the delivery format. It makes little sense to transfer a DSD 64 recording with all of its inherent "out of band" noise to a 192 kHz/24-bit PCM file… although there are plenty of vendors doing exactly that." said Waldrep.

So a 'studio master' must be of audiophile level quality and will bring out the best in our high-end music reproduction systems yes? No.

"The music that we consume is deemed complete when the mastering is finished and approved by everyone involved with the project. The artists, the producer and the record company have to all agree that the album is ready for the target market…the commercial music marketplace. It has to be able to play on the radio, in your car, through ear buds and headphones as well as at home. Can you imagine how difficult it is to craft a single master recording that will work equally well in all those environments? It's very difficult and demands that sonic compromises be made. The master is NOT optimized for audiophile systems and golden ear listeners. We’re not getting all that we hope for." said Waldrep.

He continued "when people say they want the "studio master" they really don't know what that means. It assumes that there is a single ultimate quality analogue tape or digital file that is the definitive statement of fidelity for an album or track. The music production world just doesn't work that way."

Waldrep decided to investigate some of the downloads available for purchase from the French site, Qobuz.com, which has been rapidly growing in popularity. What he found after downloading and anaylsing two 'high resolution' files was disconcerting.

"Here’s the spectrogram of the first file. The title of the piece is “Mere de Dieu Vierge” and it is a performance by an a cappella vocal ensemble. Human voices don’t put out a large amount of high frequency sound so I wasn’t expecting too much with this track. What I discovered was a track that had been rolled off at 23 kHz! This was advertised as a 192 kHz/24-bit track and is intended to be used to evaluate very high sampling rate material. Take a look:

Figure 1 – A spectrogram of a “192 kHz/24-bit” demonstration file from QoBuz.com

The fact that this plot goes to absolute zero means that they used a low pass filter to exclude any frequencies that might have been in the recording space beyond standard CD resolution. I just can’t figure it.

The second track was recorded at 176.4 kHz. It’s a jazz trio featuring an acoustic bass. We would expect it to contain a reasonable amount of high frequency material due to the drum set. This time there’s no roll off…although the track would probably benefit from a LPF because there’s a few oscillations in the upper spectra and a large amount of noise in the highest frequencies. My guess is that this track was recorded using analogue tape and that there was some ultrasonic noise present in the studio. Here’s the spectrogram:

Figure 2 – A spectragram of a “176.4 kHz/24-bit” demonstration file from QoBuz.com

It’s pretty clear that the French site has some misunderstandings regarding high-resolution audio. Unfortunately, the amount of misinformation being put forth about high-resolution audio is widespread".

So you see it's simply a case of buyer beware. The music business has always been about, you guessed it, selling music. High resolution downloading has enabled labels (and sites) around the world to sell music direct, easily, and to sell more of what would otherwise be archived or out of print.

Dr. AIX is dedicated to his belief in true 'high resolution', and through his own download site www.itrax.com, which is constantly evolving, hopes to raise awareness of the current issues relating to high resolution downloads, and perhaps dispel a few myths and even operators in the current market at the same time.