Bench Talk

Recently I attended the 137th Audio Engineering Society (AES) Convention in Los Angeles. If you aren’t familiar with the AES Convention it’s a small event that hosts a pro audio trade show along with a wide range of technical sessions for design engineers developing new audio products. This year the AES technical programs featured a product design track that covered networked audio, analog-to-digital (A/D) and Digital-to-Analog (D/A) design for high-resolution audio (HRA). Some of the best producers, recording engineers, and audio hardware designers in the world attend to participate in workshops and make themselves available for questions. If you’re designing products that include audio and have never attended the convention you might want to consider looking into next year’s convention.

Of course all conventions start with the keynote speech. This year’s keynote was delivered by Alan Parsons, best known for his contributions as recording engineer for critically acclaimed albums such as Pink Floyd’s “Dark Side of the Moon”, Al Stewart’s “Year of the Cat” and five albums from The Hollies. I have to admit, at first I was a little confused by his message. One usually expects an upbeat, “let’s get this party started” kind of speech, but that’s not what happened. Alan Parsons was obviously frustrated and maybe even somewhat angry. His speech focused on the way consumers purchase and listen to music and the limited availability of high resolution music for consumers. It quickly became clear that his message was a call to action for everyone involved in the creation of music to raise the bar. So, what’s wrong with the music we have now? Mr. Parsons provided a brief comparison of the various popular download formats and the shortcomings of each, specifically MP3 which is by far the most popular download format. He followed the discussion with a question. “How did we let this happen?” Based on the keynote speech, it’s no surprise that high-resolution audio was a major focus at the 137th AES Convention.

But wait; many in the music industry have already been recording at 24-bit 96 kHz (or 192 kHz) for some time now, so doesn’t high resolution audio already exist? Yes, it does, but unlike HDTV manufacturers who were able to reach an agreement on the HDTV specification, there’s been little effort to develop agreement on defining HRA and how to promote it – until now. Recently the Digital Entertainment Group (DEG), working with the Consumer Electronics Association (CEA), the Recording Academy, and several major labels, announced the release of a formal definition for High Resolution Audio. The press release states:

High Resolution Audio is defined as “lossless audio that is capable of reproducing the full range of sound from recordings that have been mastered from better than CD quality music sources.” In addition to this definition, four different Master Quality Recording categories have been designated, each of which describes a recording that has been made from the best quality music source currently available. All of these recordings will sound like the artists, producers and engineers originally intended.

They don’t define a true specification; however, the four Master Quality Recording category descriptors provide a few additional details:

MQ-P: Recordings mastered from a PCM master source of 20-bit at 48 kHz or higher; (typically 24-bit/96kHz or 24-bit/192kHz content)

MQ-A: Recordings from an analog master source

MQ-C: Recordings from a CD master source (16-bit/44.1 kHz)

MQ-D: Recordings from a DSD/DSF master source (typically 2.5 or 5.6 MHz content)

Again, it’s not a specification. But at least it is an agreement that brings multiple organizations together to support and promote high resolution audio for consumers.

As mentioned earlier, HRA has been with us for a while. Some of you may remember the two formats that were competing for consumer acceptance in 1999. It was Sony-Phillips who released the Super Audio Compact Disc (SACD), while the DVD Forum promoted their DVD-Audio format. While neither format “won” the technology, each continues to make contributions today.

Another development that began in the 1990’s was the growth of online music downloads in popular formats like MP3 and AAC. Now, there are multiple HRA download sites like HDtracks, Acoustic Sounds, iTrax and others providing lossless (uncompressed) files in a variety of formats (FLAC, ALAC, DSD, AIFF, etc.) Recently Neil Young’s new company, Pono, made headlines by supporting HRA downloads and even providing a dedicated playback device ($399) designed to play HRA files. This is an interesting approach that’s understandable since portable products (smartphones) are the most common music playback devices but they’re not really designed to reproduce high quality music.

It’s still early in the promotion process and HRA music sales are slowly growing, but sales are being driven primarily by the audiophile community. The good news is there’s a great deal of weight being put behind HRA sales by the aforementioned groups, and many consumer audio product manufacturers are developing new products designed to take advantage of HRA. Yet there are still a number of challenges to overcome, which include higher costs for music files and playback components; although I expect the cost of HRA to drop over time. In reality, there’s no additional cost to produce HRA files. Added costs are not in the production but rather in the resources required to support higher bandwidth downloads.

The challenge of overcoming higher hardware costs is very real. Due to the higher cost of high resolution ADCs and DACs, industries that support high resolution audio find themselves competing for consumers who have more choices than ever. If HRA music takes off, it’s possible that economies of scale could help lower costs. In the meantime, there’s still a small but growing market to support HRA and some major proponents are combining efforts to provide music the way artists intended. In order to make this happen it requires everyone from engineers designing and creating new products to capture and reproduce audio, and everyone involved on through each stage of the production process. Every stage of recording, mastering, and encoding the final product for download provides an opportunity for new designs supporting high resolution audio that provide the intended, and therefore the best, listening experience.