After replacing the LS50s with the not-yet-broken-in KEF Q350s, I restarted Eis Thanaton. Three minutes in I was staring blankly, eyes closed, swaying slowly in my seat, astounded by how much…
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During the hour preceding my removal of the KEF LS50 loudspeakers from their spiked, rough-iron stands, I was lost in the recurring still moments, reverberating tones, and contemplative spirit of Sir John Tavener's Eis Thanaton and Theophany, in the recording by soprano Patricia Rozario, bass Stephen Richardson, and Richard Hickox conducting the City of London Sinfonia (CD, Chandos CHAN 9440).
The Q350s really liked tubes, especially push-pull EL34s. With the PrimaLuna Prologue Premium stereo amplifier ($2199) and preamplifier ($2199), the modest KEFs' bass was less taut, but they delivered a fleshy, organic-feeling midrange and elegant, delectable highs. The PrimaLuna amplification had a satisfying way of filling out the Q350's tendency toward thinness. The combo made male and female voices—such as those of Furia Zanasi and Ximena Biondo of La Chimera, in their Buenos Aires Madrigal: Argentine Tangos & Italian Madrigals (CD, MA M063A)—feel more embodied and tonally complex,…
Sidebar 1: Specifications
Description: Two-way, bass reflex, stand-mounted loudspeaker. Drive-units: a single Uni-Q coincident driver array comprising a 1" (25mm) vented aluminum-dome tweeter and 6.5" (165mm) aluminum-cone woofer. Crossover frequency: 2.5kHz with first-order slopes. Frequency response: 63Hz–28kHz, ±3dB. Sensitivity: 87dB/2.83V/m. Impedance: 8 ohms nominal, 3.7 ohms minimum.
Dimensions: 14.1" (358mm) H by 8.3" (210mm) W by 12.1" (306mm) D. Weight 16.75 lbs (7.6kg).
Finishes: White with silver drivers, black with black drivers.
Serial numbers of units reviewed…
Sidebar 2: Associated Components
Analog Sources: AMG Giro G9, MoFi Electronics UltraDeck turntables & tonearms; EMT TSD 75, Koetsu Rosewood Standard, Miyajima Saboten, MoFi Electronics MasterTracker cartridges.
Digital Sources: Mytek HiFi Manhattan II, Schiit Audio Yggdrasil DACs; Integra DPS-7.2 DVD player (used as CD transport).
Preamplification: Auditorium 23 (for EMT TSD 75), Bob's Devices CineMag 1131, Dynavector SUP-200, Lounge Audio Copla JFET-MC step-up transformers; Lounge Audio LCR Mk.III RIAA, Parasound Halo JC 3+, Tavish Design Adagio phono preamplifiers;…
I got an e-mail last summer from my colleague Tyll Hertsens, editor of our InnerFidelity website. "Recently reviewed and really liked the new MrSpeakers Æon," he wrote. "They're a little rough-sounding as sealed headphones tend to be, but the tonal balance is superb. I got three in for review to make sure they're consistent. After measurements I asked [MrSpeakers'] Dan Clark if I could forward them to you because I like them so much and thought you should hear them. . . . I really think you may enjoy them."
I've never been a fan of close-backed cans, although I used to use a pair of Sony…
Sidebar 3: Measurements
I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the KEF Q350's frequency response in the farfield, and an Earthworks QTC-40 for the nearfield responses. My estimate of the KEF's sensitivity was 86.6dB(B)/2.83V/m, which is within experimental error of the specified 87dB. Though the impedance magnitude (fig.1, solid trace) drops just below 4 ohms at 180Hz and there is a combination of 5 ohms and a –39° electrical phase angle at 125Hz, the speaker is a relatively easy load for the partnering amplifier. This graph was taken with the port…
Sidebar 1: Specifications
Description: Closed-back, circumaural headphones with planar-magnetic drive-units featuring V-Planar and TrueFlow technologies. Frequency response: "We don't publish a spec because too many vendors shamelessly exaggerate the response of their headphones to inflate their numbers, making any comparison of specs irrelevant." Impedance: 13 ohms. Sensitivity: 93dB/1mW. Supplied accessories: carrying case, foam-pad filters, detachable fabric-covered headphone cable with "Hirose-style" connectors at headphone end and ¼" and 3.5mm dual-tip plug at other end.
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Sidebar 2: Associated Equipment
Digital Sources: Mac mini running Roon 1.3 & 1.4; Ayre Acoustics QX-5 Twenty D/A processor–headphone amplifier; PonoPlayer.
Headphone Amplifier: Naim Audio Uniti Nova.
Headphones: Audeze LCD-X, Thinksound On2.
Cables: Digital: AudioQuest Vodka (Ethernet). Headphone: manufacturers' own. AC: manufacturers' own, AudioQuest NRG (Niagara 1000).
Accessories: AudioQuest Niagara 1000 Low-Z Power/Noise-Dissipation System, Quik-Lok stand.—John Atkinson
Sidebar 3: Measurements
I didn't measure the MrSpeakers Æons' frequency response, as I lack the necessary simulated head and torso, and estimating the optimal response of headphones is far from simple. (Tyll's review includes a full set of acoustic measurements.) However, I used my Audio Precision System One to measure the Æons' impedance and electrical phase with the headphones mounted on my head. The impedance was a constant 13.4 ohms across the audioband, and the phase angle was 0° up to 10kHz, suggesting that each drive-unit behaves as a pure resistor up to that frequency; the…
The hoary question of tubes vs transistors, once certain and clear, is made ambiguous by recent products from a few solid-state specialists, not the least being Ayre Acoustics—the company that endures in the wake of the passing of its founder, the widely admired Charley Hansen. In their solid-state preamplifiers and amplifiers of the past decade in particular, Ayre has enshrined a number of technologies that are more than just variations on the audio-engineering status quo, and that appear to pay real sonic dividends.
Consider Ayre's Variable-Gain Transconductance (VGT) circuit,…