Mark Waldrep Knows What He's Doing
by Andrew Quint
On what seems to a visitor from the steamy East Coast an impossibly beautiful July afternoon, I’m sitting at Dr. Mark Waldrep’s mixing console, in cool semi-darkness. I’m in Los Angeles for a family wedding and have planned to meet with Waldrep, the man behind AIX Records and iTrax, for a demonstration of his live action music 3D Blu-rays. Waldrep isn’t here: he’s been called to Nashville to caucus with Naxos regarding distribution of his chronically underappreciated recordings, a major coup. But the engineer/producer has suggested that I stop by anyway. We talk by phone for a while, then an assistant plays me selections from AIX’s 3D Blu-ray music demo disc that range from a Mozart string quartet to solo jazz piano to Mark Chesnutt’s country band to Rita Coolidge belting out "Brickyard Blues." The 3D video aspect is interesting—if, for me, unessential. But the multichannel audio, emanating from five B & W 801 loudspeakers, is quite simply the most realistic and involving instance of recorded sound I can recall, from any source format. Mark Waldrep knows what he’s doing.
The PhD, by the way, isn’t in electrical engineering or some other scientific or technical discipline, as I’d assumed. The degree is in music composition: at UCLA, Waldrep submitted the first-ever electronic music doctoral dissertation. He took a dummy "binaural" head and a stereo NAGRA IV-S battery-powered field recorder into various acoustic environments—a cave, the beach, up in a hot air balloon—and used these binaural recordings as the raw materials for a composition. Waldrep’s musical activities in those days were quite diverse, to put it mildly. He wrote musique concrète but was also a capable rock guitarist. He studied composition with Mel Powell and Morton Subotnick, and was selected to attend master classes with Pierre Boulez while a student at Cal Arts. Yet around the same time Waldrep landed an engineering job at Mama Jo’s Recording in North Hollywood, where he worked with the likes of the pop/rock band Ambrosia.
It was in the context of all this musical activity that Mark Waldrep’s recording philosophies developed. Watch the videos that accompany many AIX DVD-Audio and Blu-ray releases and you’ll note stereo pairs of microphones positioned close to individual instrumentalists and vocalists. "It’s not panning a mono signal among speakers or adjusting reverb and dynamic levels that gets you the sense of physical placement in a surround field or even a stereo field," Waldrep told me. "It’s about the mechanisms of what we have built into the sides of our heads—our ears— and the processing of that information in our brains."
Waldrep elaborates: "There’s a reason why we have two ears and it’s not just so that we can tell whether a perceived sound is coming from our left or right. A far more important aspect of binaural sound is the ability to discern how far away a particular sound source is from us. This evolutionary development ensured that humans and animals would have an early warning system when it came time to get away from predators. It's the same reason why we have two eyes and experience the world in full stereovision. It's all about ‘depth’ of vision or sound.
"Unfortunately, most traditional studio/commercial recordings are done using a single microphone placed near the instrument. The recorded sound is then electrically panned between an array of speakers, artificial reverberation is added, and the perceived distance to the sound is controlled exclusively by the amplitude of the track; the lower the volume, the farther away the object producing the sound is. The problem with this type of audio engineering is that the reproduced sound never breaks the perimeter of the monitor speakers. Getting inside or outside of the ‘circle’ of speakers is almost impossible using mono sources. However, if you record with the space in mind using a stereo pair of mikes and carefully arrange them in the mix, it can make the speakers disappear and transport you into the space where the original performers were playing."
AIX typically includes two multichannel mixes (in addition to a stereo version) on its releases—a traditional "Audience Mix" and a more aggressively enveloping "Stage Mix." Waldrep’s preference is clear. "The sound of highly reverberant classical recordings is not something that I personally value," he says. "As a guitar player, I've played in a number of bands and always enjoyed being close to the sound coming from the other guys in the group. My epiphany moment came when my piano instructor, Gaylord Mowrey, invited me to one of his solo recitals. On the program that afternoon was a single piece of music, a two-hour-long solo piano work by the late Morton Feldman. As I walked into the Roy O. Disney hall, a modular room with no stage or raised portion, I saw the piano was in the middle of the space. There were no chairs. The audience area, which surrounded the piano, was covered with rugs and pillows. Listeners were invited to recline for the lengthy program. My teacher came up to me as I entered the space and told me that he had reserved a very special location for me—directly underneath the nine-foot Steinway grand piano! That afternoon, as I drifted in and out of consciousness listening to Gaylord playing the Feldman piece, my perspective on the traditional audience placement during a music performance changed.
"So it was natural for me to think about being on stage with the musicians, in the midst of the performance. In fact, this is the default on our releases because it forces the listener to confront a mix that fully immerses you in the music. People have said ‘Well, this is another conductor-wannabe mix and I feel like I’m standing on the podium.’ Well, what’s the matter with standing on the podium? Look, if everybody had the opportunity to be up there with [Gustavo] Dudamel or Zdeněk Mácal and the New Jersey Symphony Orchestra, I think you might come away with a different appreciation of Pines of Rome— with 120 decibels hitting you from 30 feet away, as opposed to being in the 20th or 30th row. It’s all about personal taste. For me, the more involving, the better."
A sore subject with Mark Waldrep over the years has been his decision to use the DVD-Audio platform for his high-resolution recordings, rather than SACD. He’d bristle if the obvious was pointed out in print—that DVD-A was fading fast as a commercial endeavor. Of course, with the ascendance of Blu-ray—including its use as a music-only carrier—Waldrep has been vindicated, in terms of the evolving dominance of PCM-based recording over the Direct Stream Digital methodology. "I'm not a fan of DSD technology and have a hard time comprehending the ‘success’ of SACD over DVD-Audio. I can only guess that Sony/Philips did a much better job of marketing its ‘revolutionary’ archival technology than the forces behind DVD-Audio did.
"I'm a member of the CEA Audio Board and another board member distributed a handout that was meant to illustrate the benefits of DSD over CD-quality PCM. There were two spectragraphs on the piece of paper. The upper frequencies on the PCM graph were clean and surrounded by black—no sound—as you would expect. However, the DSD graph of the same music had a very definite ‘purple haze’ in the band between 25 kHz and 35 kHz. This was the result of the noise-shaping algorithm of the DSD process. Most mastering engineers simply roll off these unwanted HF components. So the question I asked myself was: ‘If one of the goals of the new formats is to increase the HF extension and accuracy of the recording, which does it better, PCM or DSD?’ I made my choice and only use HD PCM to represent the digital audio we capture.
"Blu-ray offers the best combination yet for combining HD surround music and HD video. Where we previously had to down-convert our videos from HD to anamorphic SD video and use a lossy audio encoding technology like Dolby Digital or DTS for the surround mixes, now we can have uncompromising HD audio and HD video quality, thanks to the next generation of optical disc technology, the Blu-ray disc. I couldn't be happier with the sound and accuracy of the TrueHD encoding methodology from Dolby Laboratories. It is a continuation of the Meridian Lossless Packing (MLP) algorithm of the DVD-Audio format and provides 100% accurate reproduction of the master digital files."
Another subject about which Mark Waldrep has strong feelings—very strong feelings—is high-resolution downloads. He launched iTrax in 2007 for the online sale of AIX recordings and the site also has material from a few other labels, including Harmonia Mundi and 2L. Waldrep is prickly about what counts as a high-resolution music file and a banner on the AIX website sums it up: "Home of REAL High Definition Recordings."
"I define high-definition audio—whether it comes from a disc, memory stick, the ‘cloud’ or wired file transfer—as audio that was recorded, at the time the original musicians were present, using equipment that has the capability to achieve or exceed the dynamic range and frequency response of human hearing. In the language of PCM digital encoding, this translates to a sampling rate of at least 96 kHz and word lengths of at least 24 bits. I’m not willing to debate the upper range of human hearing: if a musical instrument/singer produces frequencies above the traditional 20 kHz ‘highest’ end of human hearing, producers/engineers should capture those frequencies and deliver them through the playback systems to consumers. I know there are high partials above 20 kHz in the sound of cymbals, violins, and a trumpet using a Harmon mute: I've seen them and experienced them. We have speakers that can reproduce frequencies this high, so why not provide them to music fans? It's about coming as close as possible to the actual music-making event.
"According to Nyquist, a sampling rate of 96 kHz provides recorded frequencies up to 48 kHz and gives equipment designers much greater flexibility in the implementation of filters in their ADCs and DACs. It also minimizes the interaural delays that can happen between different recording channels, resulting in better spatial resolution and clarity. So it's not just about extending the highest frequencies above the traditional range of human hearing. The use of 24 bits means that the full dynamic range of a musical performance can be maintained during the entire recording chain. This provides a theoretical upper limit of 144 dB of dynamic range (the reality is closer to 120-125 dB) but this is far better than the best analog tape machines can muster."
But doesn’t a Golden Age analog recording that is digitally remastered at 24/96 count as HD, representing as close an approach to the original mastertape as consumers can get? Waldrep doesn’t buy it.
"Think about it. If you take an analog recording—which usually started as a 24-track master that was mixed to another analog 2-track tape and then was mastered to another tape only to be copied to yet another tape—that has 55 to 60 dB of dynamic range and transfer it into an HD PCM ‘bucket’ capable of 120 dB of dynamic range, does the fidelity of the original analog tape adopt the sonic profile of the new HD environment? No, it stays the same as it was at the last point prior to the digital transfer. It's true that you don't lose any fidelity during the transfer but you don't gain any additional dynamic range or frequency response either. It may sound ‘better’ than the original to some reviewers' ears but that is likely due to creative remastering and not the additional fidelity possible with HD formats.
"A standard definition recording will always be a standard definition recording because the fidelity is locked in at the time of the original session. Those who would elevate analog tape and vinyl to HD status are essentially saying that we've had HD audio since the 1960s and that the advances in fidelity haven't improved in the intervening 50 years. I don't accept that. I believe there are lots of very high quality recordings that eclipse the best of the analog era."
The full-boat 24/96 two-channel and surround options for iTrax downloads are costly—$21.99 and $27.99 per album, respectively—and this is the case with other online purveyors of HD files as well. Waldrep is frank about the pricing of his iTrax offerings: "The price of a digital download is based on a number of factors just as the price of physical goods is based on the cost of production, marketing, and distribution. There are costs associated with the bandwidth and monthly storage fees charged by the ISP, but they don't warrant the wide variety of pricing that you find on the different HD download music retailers.
"I recognize that my productions are more costly than many other high-end music labels working with digital releases. However, considering that audiophiles are willing to pay $30 to $50 for a single piece of vinyl or many hundreds of dollars for an analog tape copy of a standard definition archival release and even thousands of dollars for interconnect and speaker cables, I don't feel that spending around $30 for a true HD music album is out of line."
Early on, AIX offered a video version of a disc’s program along with the various audio-only options. I mention to Waldrep that when the visual perspective of a performance changes but the audio perspective doesn’t, it can be confusing, even jarring to many consumers. Waldrep told me: "This is the most commonly asked question I get whenever I give a demonstration in my studio or at a trade show. ‘I hear the drums on the right side of the surround mix but the drummer is located on the left side of the stage as presented by the video.’ My response is that AIX Records is a record company that specializes in producing some of the world's best music recordings. Because we record all of the musicians at one sitting, I decided it would be worthwhile to include video on the discs we release. After all, it's just a matter of a few cameras and some editing time later, right? But the music comes first.
"As the audio mixer and the video editor, I have a choice to make when working with both media. The video could be a single locked-off camera looking at the group from the audience with the audio mixed to match the position of the musicians on stage or I could edit the video to be more interesting than a single camera and disconnect from the physicality of the placement of the musicians. I chose to mix the music tracks independently of the visuals. Clearly, I could chase the visuals with the mix—have the drums instantly jump from one position in the mix to another as the video cuts. This is not a viable choice. Remember these are music albums with video and not the other way around. If the disconnect bothers a particular listener then simply turn off the video."
Mark Waldrep has a number of "firsts" in his resume. The AIX Media Group was the first to release an "enhanced CD" and, in 1997, the first to author and release a DVD. His company developed "motion menus" and Internet connectivity for the DVD format. Now, Waldrep can take credit for the first 3D music Blu-ray discs.
"About a year and a half ago, I decided it would be fun to try and enhance the ‘private performance at home’ concept that AIX Records has pioneered over the past ten years. Panasonic Professional Products was in the midst of developing their first ‘semi-professional’ 3D camcorder and I asked if they would be interested in providing four of their prototypes for a few days so that we could shoot the first 3D music albums. They agreed. The 3D imagery was amazing. What I though would be a curiosity or gimmick became a transformative experience."
Mark Waldrep’s success derives, in part, from his unusual skill set, a rare combination of scientific discipline and artistic imagination. "I have a very strong left/right brain connection," he says, without a trace of braggadocio. "I can program computers and do math really well and I can write a melody and play the guitar." It could be added that Waldrep also has a restless curiosity that keeps him on the lookout for the latest technological developments that might further elevate the experience of listening to music at home. "It’s not, for me, about the traditional audiophile goals of a producer or engineer to recreate the acoustic reality of a physical performance. That’s not my goal. It never has been. It’s to maximize the creative, expressive output of a composer’s musical thought using the best technology we can. We have much more flexibility to do that these days than we ever had before."
Yes, Mark Waldrep knows what he’s doing.