A cure for proliferation and redundancy
One of the downsides of assembling a state-of-the-art audio system is the proliferation of boxes for differing sources. On the digital side alone, my system has relied on three separate devices: one each for computer audio (a USB digital-to-analog converter), for SACD and CD, and for DVD and Blu-ray. Separate boxes mean multiple interconnects, power cords, and rack shelves -- an expensive proposition. Perhaps most frustrating is the knowledge that so much of what each box contains is redundant: digital filters, DAC chipsets, clocks, analog output stages. Nevertheless, no single digital device, to my knowledge, came close to providing edge-of-the-art performance with all of these disparate formats. It was therefore an exciting day last summer when Ayre Acoustics announced the imminent release of its DX-5, a new digital source component billed by Ayre as a Universal A/V Engine ($9950 USD).
The DX-5 is a single-chassis digital player with a transport able to spin all commercially available 5" silver discs -- CD, SACD, DVD-Audio, DVD-Video, and Blu-ray -- as well as a USB input capable of receiving datastreams from the "Red Book" standard of 16-bit/44.1kHz to high-resolution files of 24/88.2, 24/96, 24/176.4, and even 24/192. My anticipation was further enhanced by reports that the DX-5 achieved higher levels of performance with audio discs than even Ayre’s own C-5xeMP (my prior reference player) -- or, with computer audio, Ayre’s QB-9 USB DAC. The QB-9 has been part of my reference system for the past 18 months, and both it and the C-5xeMP are SoundStage! Network Recommended Reference Components. As a bonus, Ayre has included video playback in the DX-5, with an attention to detail unheard of in my experience. That all of this functionality could be contained in a svelte aluminum case requiring only a single AC cord, one set of analog interconnects, and one shelf space seemed almost too good to be true.
Slimming down
True to Ayre Acoustics practice, the DX-5’s packing materials are as earth-friendly as they are effective. The player comes double-boxed, wrapped in a thick polyethylene bag, suspended between two opposed, trampoline-style frames, and accompanied by a standard IEC power cord, a USB cable, a registration card, and a manual. For any device offering such extreme functionality and flexibility, reading the manual is a must. Luckily for customers and reviewers alike, Ayre’s founder and resident visionary, Charles Hansen, has paid as much attention to the DX-5’s guide book as he has to its electronics. The logical organization, straightforward descriptions, helpful hints noted with a light-bulb icon, settings checklist, and glossary allow for quick setup and immersive customization.
Unboxed, the streamlined DX-5’s brushed-aluminum panels, soft-beveled edges, and central blue display make it immediately recognizable as a member of Ayre’s "5" series, though at 17.25"W x 3.75"H x 12.5"D it’s about a full inch shorter than the K-5xeMP or C-5xeMP. The elegant front panel and controls are dominated by two principal elements: a rectangular aperture at the center of the thick aluminum faceplate frames the disc tray (top) and the blue LCD display (bottom). To the right is the control ring -- a multifunction, highly intuitive user interface enabling the functions of Play, Pause, Stop, Open/Close, and Skip, as well as up, down, left, and right cursor controls for navigating the onscreen menus. There’s a status LED at the control ring’s lower left, an On/Standby button at the lower right.
The DX-5’s rear panel, by contrast, is fully occupied with inputs, outputs and system-integration ports. Starting from the upper-left corner are: the analog audio two-channel outputs, one pair single-ended (RCA) and a second pair balanced (XLR); directly below them are the USB input and HDMI audio output, and to their right an AES/EBU digital audio output (XLR) and a composite-video output. At the bottom center of the rear panel are three ports, labeled Ethernet LAN, USB Host, and HDMI A/V Output. At the far right, past a whisper fan and a row of small ventilation slots, are the IEC power input, a pair of AyreLink ports, and four DIP switches for system optimization. There’s plenty of room for customers to connect their favorite, oversized, audiophile power cords and interconnects. I found that the fan almost never ran when I played music, and when it did -- usually during Blu-ray startup -- it wasn’t nearly as noticeable as that of my Oppo Digital BDP-83SE universal Blu-ray player, presumably because it’s been designed to run very quietly, with ball bearings to ensure long life.
Packing it in
The DX-5’s low-slung exterior has necessitated a compartmentalized, layered interior. Some products, when opened up, beg the question "Where’s the beef?" -- their insides are mostly air. Not this Ayre. Rather, the question that came to mind as I examined the DX-5 was the one I ask when peering under the hood of a Mercedes AMG C63: "How did they shoehorn all that in there?" Ayre makes the most of the DX-5’s limited real estate, packing in four prime subsystems: a transport/video board, a USB receiver board, two transformers/power supplies, and, finally, the engine itself -- the analog audio output board. Each deserves analysis.
The first and potentially most controversial is the transport/video board. Ayre mines these subcomponents largely intact from Oppo’s BDP-83 Blu-ray player, but replaces all of the board-level switching power supplies with discrete, linear ones, and uses its experience with precise, low-jitter master clocks to extract tighter tolerances from the video clocks. From the design team’s perspective, there are several benefits to outsourcing the transport mechanism and video board. First, starting with one of the most robust universal transport mechanisms -- it reads BD-Video, DVD-Video, DVD-Audio, AVCHD, SACD, CD, HDCD, Kodak Picture CD, CD-R/RW, DVD±R/RW, DVD±R DL, and BD-R/RE -- and similarly accomplished video-processing chipsets, Ayre can apply its perfectionist point of view to achieve even higher performance. Second, Ayre can bypass the BD and DVD licensing fees manufacturers must pay. Third, they can piggyback on Oppo’s firmware support, one of the best in the business, to ensure compatibility with future Blu-ray releases as the format matures, something no low-volume producer could ever hope to do for itself. And, as discussed in greater detail below, the transport/video subsystem has its own grounding scheme, one galvanically isolated from the DX-5’s audio sections.
The second subsystem is the USB receiver board, which is all Ayre, with a little help from Wavelength Audio and its Streamlength asynchronous USB audio solution. In essence, the receiver board is a high-speed update of the input device that debuted in Ayre’s QB-9 USB DAC. Streamlength takes advantage of the asynchronous delivery options embedded in the USB standard, allowing a high-precision, fixed-frequency clock in an outboard DAC to be the master to which the computer’s output is slaved, effectively eliminating jitter to a level well below 10 picoseconds. In the DX-5, music files of up to 24-bit word depth and 192kHz sample rate are supported by the high bandwidth of the USB Audio 2.0 protocol and drivers, with one fixed-frequency clock dedicated to the 44.1kHz sampling rate and its multiples (88.2 and 176.4kHz), and a separate clock dedicated to 48kHz and its multiples (96 and 192kHz). Speaking of slaves, whenever the USB receiver is locked to a computer outputting an active bitstream, the DX-5’s USB DAC functionality becomes the master, as its transport/video subsystem is fully disabled, to eliminate any mechanical or electrical interference. The receiver board is powered by the USB power bus, cleansed by micro Ayre Conditioner power-line RFI filters, and, just like the transport/video system, is galvanically isolated from the audio circuits.
The third subsystem consists of the two massive transformers and regulation for the multiple power supplies used throughout the DX-5. Consistent with Ayre’s convention, EI-type transformers were chosen over the nearly ubiquitous toroidal type. According to Ayre, their shielded EI transformers offer greater stability and clarity, superior rejection of line-borne electrical noise, and low magnetic radiation (essential within the tight confines of the DX-5). To further augment its superior rejection of noise, each transformer is preceded by a dedicated Ayre Conditioner. The transformer at the front-left corner of the DX-5’s interior services the transport/video board and the control/display functions; the second transformer, at front right, feeds the audio board with double-regulated, zero-feedback analog power supplies for each circuit.
Finally, we come to the main attraction: the analog audio output board. As mentioned above, the DX-5’s total electrical isolation of the video, computer audio, and analog audio sections is made possible by high-speed optical isolators. Whether the digital audio bitstream is sourced from the internal transport mechanism or the USB input, the stream of ones and zeros flows through opto-couplers into a Xylinx Field Programmable Gate Array (FPGA), where Ayre’s proprietary digital filter performs its tricks, then on to Texas Instruments DSD1792A D/A converter chips, which enable discrete decoding and playback of each format in its native domain (PCM or DSD). From there, fully balanced analog signals benefit from Ayre’s EquiLock gain circuit before exiting the DX-5. Charles Hansen has summarized the impact on the sound of each of the elements in this chain: "A D/A converter’s performance probably only depends about 10% on the DAC chip. The digital filter is maybe 20% (we bypass the one in the DSD1792A and roll our own in an FPGA), the clock is maybe 20%, and the other 50% of the sound quality comes from the analog circuitry and the power supplies."
In essence, Ayre has combined the best aspects of the digital conversion and analog output stages of its C-5xeMP disc player and QB-9 USB DAC to achieve a new level of performance in the DX-5. Using the foregoing description of throughput as a guide, let’s delve deeper into the technology implemented in the DX-5’s audio analog board.
A continuation of the research and development that resulted in the MP upgrade for the C-5xe and the release of the QB-9, the DX-5 includes state-of-the-art digital filters that are proprietary to Ayre (they’re firmware upgradeable), and are an extrapolation of Peter Craven’s groundbreaking 2004 paper for the Audio Engineering Society on apodizing minimum-phase digital filters. Minimum-phase filters primarily differ from their linear-phase brethren (the standard design used in over 99% of all digital recording and playback devices) in avoiding pre-ringing, a filter byproduct alien to the analog world in which the human ear/brain interface evolved, and which is discussed in great detail in a white paper available on Ayre’s website. The DX-5 incorporates two minimum-phase alternatives, labeled Listen/Measure, and selectable by the user via those rear DIP switches. Measure is essentially a textbook adaptation of the apodizing filter advocated by Craven, while Listen is unique to Ayre and features a gradual rolloff as it approaches the Nyquist frequency of half the signal’s sample rate (e.g., 22.05kHz for the 44.1kHz sample rate of a "Red Book" CD). When such a slope is used, the post-ringing of the filter is significantly reduced to about one cycle, though at the expense of a slight rolloff in the uppermost frequency response and a partial loss of the theoretical benefits of apodizing. Nevertheless, Ayre believes these slight trade-offs are more than compensated for by the enhanced musicality and natural sound they feel their Listen filter offers. Also notable, these minimum-phase filter designs employ a single-pass 16x upsampler rather than the usual cascade of 2x upsamplers. To my knowledge, this feature is currently unique to Ayre, who claim that it eliminates the compounding of rounding errors of the datastream.
As for the galvanic isolation of the DX-5’s analog audio board, Ayre pioneered such isolation in its D-1xe DVD player over a decade ago (separating the audio and video grounds), readapted the scheme for the QB-9 (disconnecting a computer’s ground plane from that of the audio), and has now perfected it for the DX-5 (detaching the grounds for audio, video, and computer). The reason is obvious to Charles Hansen: video and computer devices introduce significant barriers to good sound due to the radiation of RFI by switching power supplies, dozens of competing clocks of varying frequency, connecting wires, and power cords. "We do everything possible to minimize or even eliminate the electrical pollution that [video and computer devices] inherently create," he says.
The DX-5’s analog output stage features Ayre’s EquiLock circuit design, an advancement implemented in every Ayre component introduced since the MX-R monoblock amplifier. EquiLock is said to allow the circuit to operate with greater linearity and reduced distortion. In this regard the DX-5 supersedes the pre-EquiLock C-5xeMP. In the Universal A/V Engine, as in their other 5- and R-series products, Ayre taps into their precious store of new-old-stock Toshiba JFETs, their reserves of which are the envy of many an audio manufacturer. Ayre’s use of these otherwise unavailable parts and of heroic-level power supplies distance the DX-5 from the QB-9. And the power supplies feeding the DX-5’s analog audio board have benefited from Ayre’s highest level of scrutiny: each circuit is powered by linear, double-regulated, zero-feedback analog supplies.
Finally, from its digital filters onward, the DX-5’s circuits are fully balanced -- it’s a true dual-differential design. Still, single-ended outputs are provided for customers whose preamplifiers lack XLR inputs.
Gentlemen, start your A/V Engines!
Based on its pedigree and a thorough examination of what’s under its hood, I expected greatness from the DX-5. Nonetheless, Charles Hansen is quick to admonish that "one shouldn’t ever think that one can tell how something will sound by looking at the ‘specs.’ The only way to know how it will sound is to listen to it." And listen I have over the past six months, for hundreds and hundreds of hours.
From the word go, the DX-5 sounded excellent. However -- and as I’ve come to expect with Ayre’s top-level components -- several hundred hours of playback were necessary before the full measure of this player’s brilliance could be taken. While the fundamental sonic characteristics of the DX-5 remained consistent throughout this period, its refinement and transparency increased, making possible a more dynamic and engaging listening experience. According to Ayre and other manufacturers, not only do the devices in the signal path "settle in" over time to establish a more stable operating environment; the specialized circuit boards and their dielectric characteristics take significant time to coalesce electrically and mechanically. While the DX-5 was ready to charge ahead the moment I unboxed it, I suggest logging a week or two of continuous play before making a definitive judgment of its sound.
Spinning a collection of music discs
Whether spinning a CD or an SACD, my overwhelming sense of the DX-5’s playing of audio discs is best described as one of composure. While its sound was always detailed and resolving, I never felt fatigued for a moment. I exclusively used Ayre’s recommended digital filter setting, Listen, and the DX-5 had a relaxed musicality that encouraged deep engagement with the music, rather than that "edge-of-the-seat" sound that is stimulating in small doses but off-putting over the long haul. The sound of 5" discs through the DX-5 was better than I’d ever experienced at home.
Because all of my CDs are ripped as bit-perfect 16/44.1 AIFF files and are ready for playback through a computer, I primarily used the DX-5’s disc drive to reacquaint myself with my hundred or so SACDs. Beck’s Sea Change (SACD, Geffen 606949353728) is not only one of the best-sounding rock recordings available on SACD, it’s one of the few contemporary titles conceived from the start for the format. The artist’s emotional tone is moody and at times morose, and the two-channel mix, as revealed through the DX-5’s analog outputs, convincingly conveyed Beck’s post-breakup resignation and laconic melancholy, especially in "Lost Cause." The Ayre never editorialized, yet reproduced the emotional pathos of this haunted music more completely than I’d previously experienced.
Contrast the Beck of Sea Change with the high energy and sustained attack of the Pixies on their first three albums -- Surfer Rosa, Doolittle, and Bossanova (SACD, Mobile Fidelity Sound Labs 2032, 2033, and 2035, respectively) -- an unmitigated if somewhat macabre boisterousness. While lead singer Black Francis may evoke the supernatural, the extraterrestrial, and the downright strange, often all three in the same song, there’s nothing unnatural about these albums’ sound -- details and layers transcend the wall-of-sound cacophony. Through the Ayre, the energy and originality that vaulted the Pixies to the top of the indie-rock heap in the late 1980s were recaptured in song after song as vividly as I can remember ever hearing, communicating an immense visceral impact.
The DX-5 matched my longtime reference, Ayre’s own C-5xeMP, strength for strength and then added more, presumably due to the EquiLock circuit in its audio analog output stage. Not only did the DX-5 present all the same details; it seemed that a fine scrim had been removed, with the result of even greater clarity, the very last bit of restraint having been relaxed to further enhance the music’s dynamic flow. The sound’s basic nature was unaltered, but with the DX-5 I got more.
Taking computer audio up two notches
With files losslessly ripped from CDs, the DX-5’s sound was both compelling and cohesive. The upper-register energy and complex harmonic structure of horns, especially when played muted, can be a perfect stress test for playback of 16/44.1 files. Take, for example, When the Heart Emerges Glistening (16/44.1 AIFF, Blue Note), the debut album of trumpet phenom Ambrose Akinmusire, who recently was honored with a 2011 Jazz Journalists Association Award for Up & Coming Artist of the Year. Artfully fusing askew moments of discord into the harmonic progressions of songs, the split-second timing and big, bold tones of Akinmusire’s quintet demands equivalent virtuosity from the playback chain. In "Confessions to My Unborn Daughter," the dance of Akinmusire’s trumpet and the tenor saxophone of Walter Smith III sounded both intimate and intentionally harsh through the Ayre, the artists avoiding anything Pollyanna-ish in favor of more honest revelations: the fresh, fierce, vulnerable, ever-changing chronicles of a life yet unfolded. To appreciate the full measure of this buzz-worthy accomplishment requires that impeccable timing, tonality, and transparency be extracted from the source, lest the transcendent devolve into tumult. Through the DX-5, they were.
Moving up into hi-rez territory, the great got even greater. I now have hundreds of hi-rez files, stretching from 24/88.2 all the way to 24/192. What better way to sample the sonic splendor achievable through the DX-5 than Reference Recordings’ 2011 HRx Sampler -- 16 tracks of 24-bit/176.4kHz "master" quality files? Listening to Eiji Oue conduct the Minnesota Orchestra in the finale of Rachmaninoff’s Symphonic Dances illustrated what sonic summits can be scaled when a performance is captured, mastered, and re-created at a very high bit rate. The DX-5 liberated every sliver of the huge dynamic range transcribed by engineer Keith Johnson and his customized recording chain. Timpani resonated with intensity, a physically palpable expansion of the sonic conflagration emerged as the ensemble raced to its ultimate climax. With the Ayre at the fulcrum, the experience was fantastically gripping.
Like those realized by the DX-5 over the C-5xeMP, the DX-5’s improvements over the QB-9 for computer-based audio were primarily those of flow: the new player was completely unrestrained yet always in control, while offering more resolution and natural ease. In comparison with the QB-9, the result was two steps forward and no steps back. For a few music files on my hard drives the tube circuitry and transformer-coupled output of my Wavelength Audio Crimson Balanced USB DAC gave me more enjoyment, but at the expense of the DX-5’s added clarity and minimum-phase-filtering benefits. From my reference rig I prefer to hear everything, warts and all -- which is why the Wavelength was returned to my secondary system, where critical listening routinely succumbs to pure hedonism. The foregoing comparisons were all made based on listening to files of up to 24/96 resolution, because neither my QB-9 nor the Crimson has yet been updated with high-speed receiver boards. While I don’t expect the QB-9 distinctions to change post-upgrade, I’ll report on the Crimson with a full review after it’s received its full suite of upgrades, including a high-speed receiver board, opto-coupler isolation, Wavelength’s Denominator 32/192 DAC module, and the addition of volume control (to bypass any preamplifier and instead directly drive the amplifiers in my secondary, computer-audio-only system).
Music video mastery
Ever since the DVD enabled the playback of hi-rez digital audio tracks at a full PCM resolution of 24/96, many music lovers, in particular those who appreciate opera, have flocked to music-video DVDs. And now that Blu-ray offers an even higher bandwidth, that route to musical appreciation is also gaining devotees. In the DX-5, the growing ranks of these connoisseurs have an impeccable playback option for uncompromising stereo sound and video. Jeff Beck’s Live at Ronnie Scott’s (BD, Eagle Rock Entertainment EVBRD 33326-9) features a lossless, hi-rez DTS-HD Master Audio soundtrack, and the soundfield re-created through the Ayre matched this disc’s 1080p hi-def images. Beck’s mastery of the electric guitar is legendary, and in "Brush with the Blues" his wailing instrument not only spoke through the DX-5, but it laid bare his technique onscreen.
Icing on the cake
While this is a review of the DX-5 as a two-channel audio product, Ayre has also optimized its hardware for anyone wanting to use the player as a digital transport for multichannel surround. There are two HDMI outputs, one of them exclusively dedicated to audio signals. The HDMI audio output uses a high-precision, fixed-frequency clock (the same frequency used for 720p video signals) to deliver a rock-solid multichannel digital bitstream. In addition, Ayre has implemented the Auto Rate Control portion of the HDMI specification, which will, whenever implemented in a receiving processor, slave the delivery of the multichannel digital bitstream to the processor in the same way the Streamlength asynchronous USB receiver slaves the computer’s digital audio output to the DX-5’s precise, fixed-frequency clocks. For these reasons, always run the HDMI audio to a processor input dedicated to the audio signals, with a second run of HDMI cable carrying only the video. Hopefully, a processor manufacturer will implement the capability of Auto Rate Control to slave the DX-5’s precise HDMI audio output to the timing clocks that control the multichannel D/A converters.
I can’t help but praise the DX-5’s video performance. While the Oppo BDP-83SE is a world-class video source, there must be some magic in the discrete linear power supplies and clocking enhancements of the DX-5’s transport mechanism and video board. I enjoyed a level of engagement and natural ease -- again, with no sense of fatigue -- that, while perhaps not evident with test signals, was immediately obvious when I watched movies on DVD and Blu-ray. Watching our 60" Pioneer Elite Kuro plasma display, my wife frequently asked why we would even think about going out to a movie theater. With the DX-5, you can have your cake and eat it, too -- especially in a 2.0-channel home-theater system such as ours, where the disc player is the only video source.
Spring cleaning and simplicity
Digital audio has never sounded better in my system than when I use Ayre Acoustics’ DX-5 as the source. Refined, resolving, musical, and engaging, the DX-5 is exactly what the doctor ordered: an electrifying performer and an unequivocal bargain, despite its price of nearly $10,000. The folks at Ayre have outdone themselves -- the DX-5 is better than their C-5xeMP at spinning audio discs, leagues ahead of their QB-9 for computer audio, and provides 2D images of unequaled quality, without the ailments typically inflicted on an audio system by the inclusion of video. And now that the DX-5 has taken up permanent residence in my reference system (I purchased the review sample), I’ve been able to streamline my setup and regain a few shelves to host review components. I could not be happier.
. . . Peter Roth
peter@soundstagenetwork.com
Associated Equipment
- Speakers -- Vandersteen Model Seven
- Analog sources -- Spiral Groove SG-2 turntable, Centroid tonearm, Lyra Kleos cartridge; Aesthetix Rhea Signature phono preamplifier
- Digital sources -- Oppo Digital BDP-83SE Blu-ray player; Ayre Acoustics QB-9 USB DAC; Wavelength Audio Crimson Balanced USB DAC; AudioQuest Diamond USB cable; Apple MacBook Pro running Amarra music-player software
- Interconnects -- AudioQuest Wild Blue Yonder
- Speaker cables -- AudioQuest WEL Signature
- Power conditioners -- Ayre Acoustics L-5xe, Furman IT-Reference 20i
- Rack -- Harmonic Resolution Systems MXR rack with M3X shelves
Ayre Acoustics DX-5 Universal A/V Engine
Price: $9950 USD in silver (add $250 for black).
Warranty: Five years parts and labor.
Ayre Acoustics, Inc.
2300-B Central Ave.
Boulder, CO 80301
Phone: (303) 442-7300
Fax: (303) 442-7301
Website: www.ayre.com
