Recommended Components

Headphones & Headphone Accessories

Editor's Note:

We strongly recommend those interested in headphone listening visit our sister website, www.InnerFidelity.com, which is edited by Tyll Hertsens.

A

Audeze LCD-4 headphones: $3995
For their new LCD-4 headphones, Audeze uses a variation on their tried-and-true planar-magnetic technology, with a vanishingly thin diaphragm of aluminized film suspended between a push-pull array of Double Fluxor magnets (flux density: 1.5 teslas) and impedance-matching Fazor waveguides on the outer surfaces of the earcups. The supplied cable has left and right mini-XLRs for the earcups and a ¼" plug at the other end, with no adapter supplied: the LCD-4s are not intended for use with telephones. Used mostly in single-ended mode, the LCD-4s impressed JA as bass "champions" that "spoke cleanly and evenly." JA also wrote that the new Audezes "excelled in the midrange," and noted that he enjoyed the LCD-4s' "sweet" treble performance more than Tyll Hertsens did in his own review of the LCD-4s for InnerFidelity.com. Writing from his test bench, JA also noted an impedance of 156 ohms (as opposed to the specified 200 ohms) and a very benign electrical phase angle, making for an easy-to-drive pair of 'phones (but beware their lower-than-average sensitivity). The verdict: "The best-sounding headphones I've heard in the 45 years since I bought my first high-end cans." (Vol.39 No.7 WWW)

Audeze LCD-X: $1699
These large, luxurious, circumaural headphones have planar-magnetic drive-units with a thin-film diaphragm energized by arrays of powerful neodymium magnets on both sides. They employ Audeze-patented Fazor elements, said to guide and manage the flow of sound in the headphone. The circular drivers are housed in polished, black-anodized aluminum earpieces, with generously sized pads, of either lambskin or leather-free microsuede, filled with foam. Adjustment is via notched, chromed metal rods attached to each earpiece, which fit into the sprung, leather-covered headband. The LCD-Xes produced a seductive, compelling overall sound, with precise imaging, rich mids, smooth highs, and clean bass, said JA. Compared to his longtime reference Sennheiser HD650s, the LCD-Xes resolved more detail, produced the more convincing sense of recorded ambience, and provided deeper bass. "Highly recommended!" JA concluded. (Vol.37 No.3 WWW)

Aurender Flow DAC–headphone amplifier: $1295.95
In the increasingly populous field of USB DACs, the Flow leaves its mark by being compatible with iOS and Android smartphone sources. Additionally, this compact, South Korean–made DAC, powered by rechargeable lithium-ion batteries, can accept an mSATA drive (not included) of up to 1TB, thus giving it the ability to hold a great deal of music on its own. The Flow supports resolutions of up to 32-bit/384kHz, as well as DSD64 and DSD128, and allows the user to select from a range of filters. Despite an overall "light tonal balance" that made this DAC–headphone amp a better match for "relatively dark-sounding headphones like the Audeze LCD-Xes," JA enjoyed his time with the Flow: "a beautifully made, beautiful-looking, beautiful-sounding, and beautifully versatile audio component." On JA's test bench, the Flow delivered "superb measured performance." (Vol.38 Nos.6 & 12, Vol.39 Nos.1 & 2 WWW)

Ayre Acoustics Codex D/A headphone amplifier: $1795
Described by designer Charley Hansen as "deliberately built to the lowest price point we've ever done," the Ayre Codex uses a 32-bit ESS DAC chip to provide up to 384kHz PCM or DSD128 resolution via its asynchronous USB input. (An optical input is also provided but is not compatible with all devices.) Both balanced and unbalanced headphones and headphone cables are supported. JI wrote, of listening to the Codex through his Audeze LCD-X headphones, "there was plenty of detail to go around, as well as the ability to hear into the space with the performers." He elaborated: "Probably the best words to describe the Codex's aural character are neutral and detailed—and add Control, with a capital C." Writing from his test bench, JA observed that "the Codex offers excellent measured performance." (Vol.39 Nos.6, 7 & 9 WWW)

Benchmark Media Systems DAC2: $1995
See "Digital Processors" (Vol.37 No.2 WWW)

Chord Mojo: $599
Fans of James Cotton and Muddy Waters will be dismayed to learn that the name of Chord's latest D/A headphone amplifier is a contraction of mobile joy. But that is likely to be the only disappointment associated with the chunky little Mojo—which, like Chord's more expensive Hugo TT (see above), eschews an off-the-shelf DAC chip in favor of its own proprietary code, implemented with a field-programmable gate array (FPGA). The Mojo even runs the same Rob Watts–designed digital filter as its dearer stablemate, and its USB input is compatible with PCM up to 192kHz and DSD up to 11.29MHz (DSD256). No less striking are its three matte-surface glass control balls, which change color to indicate various functions and statuses. Used by JA with a variety of partnering gear—the Audeze LCD-X headphones suited it especially well—the Mojo "combined authoritative, well-defined low frequencies with smooth, detailed highs and excellent soundstaging." JA the measurer confirmed "performance that is superb for a portable device, and would not be out of place in a high-priced conventional D/A processor." But the last word goes to JA the listener: "Wow!" (Vol.39 No.2 WWW)

Focal Utopia Reference: $3999
See HR's review in this issue.

HiFi Man HE 400i headphones: $499 $$$
The least-expensive planar-magnetic headphones ST knows of, the HE-400i offers a 32 ohms impedance and 93dB sensitivity, and performs at its best with a dedicated headphone amplifier. The sound is "crisp, clean, clear, and lightning fast, as music is in real life. This is true of the bass, too. Indeed, the sound is seamless from the top down or the bottom up," summed up Sam. (Vol.37 No.12)

JH Audio JH16 Pro: $1149 (plus custom earmold fee) ★
Designed by Jerry Harvey (ex–Ultimate Ears), the top-of-the-line JH Audio in-ear monitor uses eight precision-balanced armatures (two dual-armature woofers, one dual-armature midrange, and one dual-armature tweeter) and a three-way crossover. It delivered clean transient attacks, a smooth midrange, big-hearted bass, and a detailed soundstage, said JA. The JH16 Pro exhibited excellent overall performance when driven directly by JA's iPod Classic, but offered more low-bass energy and greater articulation when driven by the Ray Samuels Emmeline The Tomahawk headphone amplifier. Price includes plastic Otterbox carrying case, felt drawstring bag, and cleaning tool. (Vol.34 No.8 WWW)

Linear Tube Audio microZOTL2.0 headphone amplifier $1100
Designed by David Berning and built in Washington, DC by Linear Tube Audio, the microZOTL2.0 (ZOTL stands for Zero-hysteresis Output TransformerLess) is a 1Wpc integrated amplifier that doubles as a headphone amp and triples as a line-level preamp. Each channel uses a 12AT7 dual-triode tube for voltage gain and phase inversion, while the two halves of a 6SN7 dual-triode comprise a single-tube, push-pull, class-A, OTL output stage. HR delighted in the sound of the microZOTL driving DeVore O/93 and Zu Soul Supreme speakers—with the latter, he said, "musical flow seemed more slippery and alive, like a trout in a clear mountain stream"—and with JH Audio Roxanne headphones, he said, "the midrange was pure and right." And "because of its radical transparency," says HR, the microZOTL2.0 "would hold its own" as a line stage "in a cost-no-object system." According to JA, while the microZOTL2.0's test-bench performance wasn't without wrinkles, "this unusual design measured well in some respects, particularly in how its linearity was not affected by the load impedance." (Vol.39 No.6 WWW)

Meridian Explorer² USB D/A headphone amplifier: $299
Hailed by Jim Austin as "the cheapest ticket into the world of MQA"—aka Master Quality Authenticated, the digital-audio format that has energized portions of the audio community and hopes to do the same for the recording industry—this reboot of Meridian's popular portable DAC-headphone amp offers more processing power than its 2013 predecessor. Specifically, its XMOS processor upsamples lower-frequency inputs to 176.4kHz or 192kHz—and, of course, allows the Explorer² to decode MQA files. Used primarily with his Sennheiser HD 650 headphones, the Explorer² impressed JCA as "very pleasant to listen to: It conveyed plenty of information in a relaxed way." In comparison, the similarly sized and priced Apogee Groove was, in JCA's words, "a little punchier . . . and a little less smooth," and the Groove lacks the Meridian's line-out jack. Of his experience with one of a handful of (unfamiliar) MQA-encoded tracks, JCA wrote of being "struck by a remarkable sense of intimacy, a close connection to the solo instrument." Writing from his test bench, JA observed that, "Like its predecessor, the Meridian Explorer² offers superb measured performance." JCA's conclusion: "a fun, capable audio device." (Vol.39 No.6 WWW)

Meridian Prime D/A headphone amplifier: $2000
Notable as much for its praiseworthy headphone amplifier and analog inputs—which, when driven by the output of an Auralic Vega DAC, sounded "rich and warm" through JA's Audeze headphones—the Meridian Prime's asynchronous USB DAC handles incoming datastreams at 16 and 24 bits and sampling rates up to 192kHz, and applies to all incoming data an "apodizing" reconstruction filter. While noting the Prime's lighter weight and smaller body as compared with the Vega, JA praised the Meridian DAC's "clearer balance." Also singled out for praise was "the palpable way [the Prime DAC] had with imaging"—which, JA mused, might be attributable to that reconstruction filter. Use of Meridian's optional Prime power supply ($1295) in place of the stock wall wart added "a touch more body, a tad more authority." In his measurements, JA found discrepancies in the Prime's 24-bit performance but praised its well-engineered analog section. The verdict: "A cautious recommendation . . . for this beautifully finished, excellent-sounding headphone amplifier." In new measurements made for his November 2015 Follow-Up, JA confirmed Meridian's hypothesis that the aforementioned discrepancies were caused by the Prime Power Supply. Still, he mused, "Why did I prefer the sound of the Prime with the underperforming Prime Supply?" As of the spring of 2016 will decode MQA data. (Vol.37 No.10, Vol.38 No.11, Vol.39 No.9 WWW)

Pass Labs HPA-1 headphone amplifier: $3500
Also usable as a line-level preamp—it has a pair of single-ended output jacks (RCA) to allow just that—the Pass Labs HPA-1 is a perfectionist-quality headphone amplifier that uses a MOSFET-based current-feedback amplifier to drive headphones ranging from 15 to 600 ohms. Its single headphone-output jack, also single-ended, is a Neutrik locking jack sized for ¼" plugs. After auditioning the HPA-1 with a variety of 'phones from Audeze, AudioQuest, and Master & Dynamic, JA declared that, "in bass quality and authority, and in midrange transparency, the Pass Labs HPA-1 is without peer." JA also brought the HPA-1 to his test bench, where it stood up to everything he could throw at it (well, not literally), prompting the appraisal: "superb audio engineering." (Vol.39 Nos.7 & 9 WWW)

Sennheiser HD 600: $399.95 ★
WP, KR, and ST were unanimous in calling these the best dynamic headphones they've ever heard. "The only ones with which I have ever been physically or sonically comfortable," says KR. "Sennheiser has kept all of the qualities that made the HD 580 among the best of its breed, and in several areas has even managed to better it impressively," according to WP. Says ST, "The magic of the HD 600s is their midrange—a purity of tone, especially when driven by tubes, that is quite special." Astonishingly transparent when driven in balanced mode by a HeadRoom BlockHead, found J-10 in July 2002. (Vol.21 No.2 WWW)

Sennheiser HD 650: $499.95 ★
The HD 650s are an evolution of Sennheiser's very successful HD 600 open-back dynamic headphones, claimed to provide superior results due to hand-selected parts with closer tolerances and the use of a specially developed acoustic silk for the driver diaphragms. Compared to the Grado SR325i, the Sennheisers sounded richer but slightly darker. JM found that their very effective seal created a resonant cavity that produced "bass that is both quite deep and a trifle indistinct." JA's new reference cans. Compared to the Audeze LCD-Xes, the HD650s had a similar overall sound, but lacked bass control, detail resolution, and ambience retrieval, said JA. (Vol.28 No.6, Vol.31 No.9, Vol.37 No.3 WWW)

Sennheiser HD 800: $1399.95 ★
Sennheiser's attack on the state of the headphone art uses a 56mm ring-radiator transducer, the largest dynamic driver currently in use in any headphone. The HD800's large earpieces are made from a combination of absorbing composites and functional metal accents, and though the 'phones' weight is 11.5 oz without cable, its clever damping and padding made it comfortable for extended listening. The HD800's Y-cable harness uses braided, Kevlar-reinforced OFC copper wire; the cable is terminated with a very substantial ¼" phono plug at one end, and two proprietary Sennheiser connectors at the earpieces. WP: "I was stunned by the Sennheisers' ability to project scale, to reveal dynamic nuance, to present timbre with realism." Compared to the Audeze LCD-Xes, the HD800s were equally revealing of low-level detail and recorded ambience, but sounded brighter, less laid-back, and lacked some bass extension and weight, said JA. (Vol.32 No.7, Vol.37 No.3 WWW)

Smyth Research Realiser A8 system: $2910 ★
Based on the Smyth Virtual Surround algorithm, the Realiser A8 subjects an audio signal to a DSP simulation of the hearing mechanisms needed for full spatial perception and then reproduces that signal through headphones, allowing users to effectively take the sounds of up to 64 different listening rooms wherever they go. The package includes the Realiser A8 processor box and power supply, the RC-1 remote control, a TU-1 Head Tracker, a TR-1 Head Tracker Reference, and two HTM-1 miniature in-ear microphones. The Realiser A8 provided the same balance and soundstaging as KR's main system, and allowed him to hear subtle differences between his Manhattan and Connecticut systems. "For the first time in my life, headphone listening was not only convincing but enjoyable," Kal marveled, adding "Class A all the way. Not only does the Realiser sound transparent as a headphone amplifier, it transforms headphone listening both in stereo and in multichannel." (Vol.33 No.11 WWW)

Thinksound On1: $199.99
ST, who hates in-ear headphones and noise-canceling headphones of any sort, liked the closed-back On1 'phones from Thinksound, a new US company whose products are made in China. The On1's over-ear enclosures are machined from the mahogany-like wood sapele, sport earpads made from memory foam (the modern pillow stuff), and are covered with faux leather. Two cords are supplied—one with a smartphone-friendly microphone, one without—along with a carry pouch of unbleached cotton. ST described the On1s as "Bass-rich, full-bodied, nonfatiguing, comfortable to wear, [and] reasonably well isolating" in their passive, closed-back manner. (Vol.37 No.7)

Ultimate Ears 18 Pro Custom in-ear monitors: $1350 (plus custom earmold fee) ★
The 18 Pro is a three-way, in-ear, custom-mold design with six balanced armatures: two each for the bass, midrange, and treble, the latter allowing the 18 Pro to have the most extended top end of any UE model. It combined clean, airy highs with a smooth, detailed midrange and deep, well-defined bass. "Its ability to play low frequencies at high levels with minimal distortion is unmatched by other in-ear 'phones, and the clarity and smoothness of its midrange is Class A," said JA. Its mid-treble might sound a little laid-back with headphone amplifiers having a high output impedance, however. Price includes personalized aluminum carrying case and cleaning tool, but does not include the custom earmold fee; optional Ambient feature allows some leakage of exterior sounds and adds $50. (Vol.33 No.12 WWW)

B

Apogee Electronics Groove: $295
After 30 years of designing and making pro-audio gear, Apogee has taken aim at the consumer market with the Groove USB DAC/headphone amplifier. Housed in a 3.7"-long aluminum case, the Groove uses an eight-channel ESS 32-bit Sabre DAC chip in a Quad Sum arrangement (four DACs per channel) for PCM input up to 24 bits and 192kHz. The Groove's (asynchronous) USB input is a Micro B socket, and its headphone output is a 1/8" jack; preceding the latter is a current-drive headphone amplifier—Apogee calls this Constant Current Drive—and a proprietary circuit that provides a variable output impedance, depending on the headphones used. Consequently, JI reviewed the Groove in combination with several different headphones (and in comparison with other DAC–headphone amps). Among the Groove's consistent strengths were its clarity and abundance of detail, which JI described while enjoying a Christy Moore track: "Through the Sennheiser HD600s, the Groove revealed every detail of Moore's great voice, each breath and reverb tail clear to the end." After conducting his measurements, JA concluded, "Overall, the Apogee Groove offers superb measured performance, which is even more impressive when you consider it costs less than $300!" (Vol.39 Nos.1 & 2 WWW)

Audeze EL-8: $699
Available in both closed- and open-back versions—HR reviewed the latter—the US-manufactured Audeze EL-8 uses planar-magnetic drivers, the diaphragms of which are made with voice-coil traces of varying thickness, intended to produce a more uniform driving force from center to edge. Audeze's acoustical Fazors, used in earlier models as response-smoothing waveguides, also appear in the EL-8. (HR suggests that the Fazor-equipped Audezes "sound more airy and transparent, but less weighty and punchy than the non-Fazor models.") Fresh from his time with Audeze's more expensive LCD-2 and LCD-X open-back 'phones, HR wrote that the EL-8s' "special beauty was their holistic way with space and inner detail," noting that, on one recording in particular, "the roof of my head became the dome of a cathedral." (Vol.38 No.12 WWW)

AudioQuest DragonFly Red D/A headphone amplifier: $199 $$$
AudioQuest DragonFly Black D/A headphone amplifier: $99 $$$
Descended from the company's popular DragonFly USB D/A headphone amplifier of 2012—a product whose price began as $249 before dropping, in 2014, to $149 with the release of the revised DragonFly v1.2—the new DragonFly Black and DragonFly Red embody a number of technical refinements. In particular, Black and Red alike use as their controller the Microchip PIC32MX, in place of the Texas Instruments TAS 1020B of their predecessors. That change allows the new AudioQuest DACs to use 77% less current than their forebears, which in turn makes them suitable for use with iPhones, iPads, and other portables. For the DragonFly Black, output voltage has now dropped from 1.8 to 1.2V, but in the DragonFly Red—which also has the distinction of an ESS Sabre 9016 DAC chip with 64-bit digital volume control—output voltage is bumped up to a healthy 2.1V, which AQ suggests better suits it to drive difficult headphone loads. (For use in driving the line-level input of a home playback system, both new DragonFlys require a cable with a 3.5mm stereo plug at one end and a stereo pair of male RCA plugs at the other.) AD remarked on the Black's greater openness and clarity over the original DragonFly, as well as its decreased bass weight, the latter associated with less boom with some recordings but less pleasant whomp with others. That said, AD wrote of preferring "the new DAC's superior musical incisiveness." The new Red, too, had less bass richness than the old DragonFly, but even "surer reproduction of pitches and timing." Yet when used with headphones, neither of the new DragonFlys was the least bit lacking in bass weight—and the Red's superior music-making was even more apparent. AD tried using the Black with his iPhone but, given the less-than-stellar sound, just didn't see the point—and surely wouldn't recommend buying the twice-as-expensive Red if use with a smartphone is all the consumer has in mind. After a false start occasioned by an unforeseen interaction between JA's test equipment and the Red's headphone amp, both DragonFlys generally acquitted themselves well on the test bench, though neither was at the head of the class in terms of jitter rejection. (Vol.39 No.9 WWW)

AudioQuest NightHawk: $599
The AudioQuest NightHawk headphones feature dynamic drivers with 50mm bio-cellulose cones, housed in semi-open earcups with 3D-printed diffuser grilles. The cups themselves are molded from "liquid wood" and cushioned with soft "protein leather" earpads. Each pair comes with two 8' cables: a rather stiff perfectionist-quality one for listening at home, and a more flexible one for greater convenience while traveling (and a balanced-mode cable is available for an additional $109.95). Initially, HR felt that the NightHawks sounded "dull, dark, foggy, and compressed"—but after being told that they require considerable break-in time, he set about giving them just that, and ultimately declared that the 'phones were "transparent in a way I haven't quite experienced before." HR's summation: "The NightHawks take my listening to classical, opera, and choral music to levels I can only describe as psychedelic." (Vol.38 No.12 WWW)

CEntrance DACport: $199 $$$ ★
Built in the US, the bus-powered DACport is a small, well-finished, tubular device 4.5" long, with a ¼" stereo headphone jack and a USB port. Although the USB interface operates in adaptive isochronous mode, CEntrance employs their proprietary, two-stage JitterGuard clock-management system. The DACport's D/A section will decode 24-bit data at sample rates up to 96kHz, and its direct-coupled output stage is claimed to run in class-A. Setup was simple; no driver is required, and the DACport is compatible with Mac, Windows, and Linux operating systems. Though it lacked the bass extension and control of the Benchmark DAC1, the DACport offered a clean, grain-free sound, with airy highs and natural transients. "A great-sounding product at a great price," exclaimed JA. (Vol.33 Nos.6 & 10, Vol.35 No.10 WWW)

Master & Dynamic MH40: $399
In the Master & Dynamic MH40, the earpads and the underside of the headband are covered in soft lambskin and the upper surface of the headband is made of cowhide. Nevertheless, democratic socialist (if not quite vegetarian) AD loved these 'phones, lavishing as much praise on their sound as on their comfort: "These Master & Dynamic headphones sounded clear and explicit—qualities they delivered in a manner that was smooth rather than brittle." AD also found the MH40s to be well balanced, with bass quantity in good proportion to their treble extension, and gave them extra points for their handy mute switch (which doubles as a right-channel indicator). (Vol.39 Nos.2 & 7 WWW)

Moon by Simaudio Neo 230HAD D/A headphone amplifier: $1500
The compact (7" wide by 3" high by 11" deep) Neo 230HAD is described by HR as "a fusion product"—a space-saving mashup of DAC, headphone amplifier, and line-level preamplifier. It has four digital inputs, of which its USB input supports PCM up to 32-bit/384kHz and DSD up to 11.2MHz, and two analog inputs: a pair of RCA jacks on the rear and a 1/8" jack on the front, the latter for the analog output of a portable device. On its rear panel are two pairs of single-ended (RCA) line-level output jacks, one with fixed output and the other with variable output. When using the 230HAD as a DAC-line stage, HR described its sound as "an informative, no-nonsense transparency that told me more [about] how the recording was made." (By contrast, he described the Linear Tube Audio microZOTL's transparency as telling him "more about how the music was played.") At the end of the day, HR concluded that the Simaudio's strongest element was its headphone amp; when he used the 230HAD with a different manufacturer's DAC, music "sounded extremely sweet, beautifully detailed, and super lifelike. Totally top-of-the-top headphone sound." JA's measurements confirmed that, "as a headphone amplifier, the 230HAD offers superbly low distortion [and] very high dynamic range," but he was puzzled by apparent modulation of the noise floor during some tests of its DAC section. (Vol.39 No.9 WWW)

PSB M4U 2: $399
The M4U 2s are closed-back, circumaural, noise-canceling headphones with a 40mm dynamic driver in each earcup. They use PSB's Room Feel equalization technology to produce an open, three-dimensional sound similar to what one might experience when listening to high-end loudspeakers in a typical listening room. Physically resembling Beats' ubiquitous Studio model, with an expandable headband and foldable polycarbonate frame (available in white, black, or red), the M4U 2s are large and bulky, but were extremely comfortable on SM's head. Unlike many active noise-canceling headphones, the M4U 2s also work in passive mode (without batteries). Though high frequencies sometimes sounded too aggressive, the overall sound was thrilling and physical, with an outstanding sense of space, excellent transient speed, and stunning dynamics, said SM. "The M4U 2s provided the most consistently thrilling headphone-listening experiences I've ever enjoyed," he summed up. (Vol.36 No.12 WWW)

Sennheiser Momentum: $349 (over-ear version)
$229.95 (on-ear version)
Sennheiser's fashion-forward Momentum models use a compact, closed-back design with a clean and sophisticated look equal parts modern and classic. The over-the-ear model is slightly larger and heavier than the on-ear, but the two have a similar overall look and feel. The oval earpieces slide up and down on the same stainless-steel headband, but while the over-the-ear design uses leather, the on-ear's earpads are covered in a synthetic material called Alcantara, which looks and feels practically identical to suede. Similarly, where the ridge of the larger version's headband is cushioned and covered in more leather, the on-ear version's cushioned headband is covered in more Alcantara. Though he loved the look and feel of both models, SM had a difficult time achieving a consistently secure and comfortable fit on his head with either, though he found the smaller on-ear version slightly more comfortable. And while both models combined true high-fidelity sound with great looks and durability, the over-the-ear design produced a bigger, more spacious overall sound, with sweeter highs, cleaner attack transients, a richer and more present midrange, and tighter bass, said SM. (Vol.36 No.12, over-the-ear version WWW; Vol.37 No.3, on-ear version WWW)

C

Audioengine D3 D/A headphone amplifier: $149 $$$
The Chinese-built Audioengine D3, like the physically similar—and similarly portable—AudioQuest DragonFly, is a combination D/A converter and headphone amplifier with a USB standard A plug at one end and a three-conductor, 3.5mm mini-jack at the other. Its shiny aluminum case conceals an Asahi Kasei Microdevices AK4396 converter chip, a Texas Instruments LM49726 op-amp, and TI's popular TAS1020B USB receiver, with firmware for asynchronous streaming. Headphone users will delight in knowing that the Audioengine's price includes a 3.5mm-to-¼" jack adapter; those who wish to drive their audio systems with the D3's 2V RMS output must supply their own miniplug-to-RCA-plug cables. SM considered the D3, fresh out of the box, "too sharp on top"—even when he factored in the inherent top-end emphasis of the Skullcandy Aviator 'phones he was using. But the brightness moderated over time, "though not at the expense of [the D3's] intoxicating speed and vibrant high-frequency color." (Vol.37 No.4 WWW)

Grado SR60e: $79 $$$ ★
The original SR60 offered a rather dark-toned balance, with a full bass and excellent resolution of detail. A more forward midrange, however. Uncomfortable. Upgrades from the original SR60 include a new driver and improved cables. While maintaining the original's freedom from obvious colorations and resonances, the SR60i went a bit deeper in the bass and had a slightly more vivid midrange for a more involving overall sound. "The SR60i is modestly better than the original, and remains one of audio's great bargains," said Jim Austin. (Vol.17 Nos.6 & 10 WWW, original, Vol.33 No.4 WWW)

iFi nano iDSD D/A headphone amplifier: $199
A mere 16 years after the DSD format first appeared on the domestic-audio market, one can now buy a cigarette-pack–sized DSD DAC with an asynchronous USB input for just $189. That product, the iFi nano iDSD, includes a lithium-polymer battery that's automatically charged via the USB bus, and supports PCM resolutions up to 32-bit/384kHz. Used in a budget desktop system with a pair of Tannoy Reveal 402 active speakers, the iFi nano iDSD impressed ML with sound that was "rich and full, with a lovely dimensional quality—the last something that often goes missing from the sound of DACs in this price range." (Vol.38 No.9 WWW)

No Class Distinctions

Etymotic Research Custom-Fit earmolds: $150–$175/pair !s
Through the nationwide network of audiologists in its Custom-Fit program, Etymotic Research produces custom eartips for its headphones for a cost of about $150/pair. (Custom-Fit Network Audiologists may charge more for an impression appointment, handling & shipping so the total price may exceed the $150 base price. It is always a good idea to verify the exact price when making an appointment with a Custom-Fit Network Audiologist.) Custom-Fit earmolds are made of soft silicone, can be formed to fit all Etymotic models, and improve on the stock Etymotic eartips' reduction of ambient noise. WP: "With the Custom-Fit earmolds, the bass is better, the midrange is clearer, and the highs are crisper—but most important, they're comfortable." Once the master molds are made, additional pairs of earmolds are available at a discount. (Vol.33 No.12 WWW)

Westone UM56 custom earmolds: $129.99/pair made of vinyl; $149.99/pair made of silicone !s
Westone's earmolds are made from silicone material impressions taken by an audiologist. When Jim Austin used the UM56s with his Shure E4s, he noted strong bass response and excellent sound isolation. A positive, secure fit requires an open-jaw ear impression. Initial moldings, formed from a relaxed-jaw impression, resulted in poor isolation and a loose fit. "Highly recommended—but open wide," said Jim. (Vol.30 No.5 WWW)

K

Audeze The King headphone amplifier, Beyerdynamic T1, Sony MDR-7506, Ultimate Ears Custom Monitors.

Deletions
Bowers & Wilkins P3 and Thinksound ms01 not auditioned in too long a time.