Description: In-ear headphones with custom earmolds, 1/8" (3.5mm) stereo plug, and optional Ambience feature. Drive-units: 6 balanced armatures with three-way crossover. Frequency range: 20Hz–18kHz. Sensitivity: 110.6dB SPL at 1kHz. Efficiency: 115.6dB/m. Impedance: 21 ohms at 1kHz. Noise isolation: 26dB.
Dimensions: Weight: 1 oz. Cable length: 48" (1220mm); 64" (1626mm) available for $45 as an accessory.
Serial Number Of Unit Reviewed: 3511-1.
Price: $1350 plus custom earmold fee; includes personalized aluminum carrying case and cleaning tool. Optional…
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Sidebar 1: Specifications
Sidebar 2: Associated Equipment
Digital Sources: Apple iPod 160GB, iPod Touch; Ray Samuels Emmeline The Tomahawk portable headphone amplifier; Benchmark DAC1 D/A converter–headphone amplifier driven by S/PDIF optical output of MacBook laptop running iTunes 10 and Pure Music 1.4; CEntrance DACport portable headphone amplifier driven by USB output of MacBook.
Headphones: Sennheiser HD650, Ultimate Ears UE-5c.—John Atkinson
Sidebar 3: Measurements
Determining a pair of headphones' optimal frequency response is neither obvious nor trivial, and is compounded by the fact that I lack a microphone small enough to insert in my ears. The only parameter of headphones that I measure, therefore, is their electrical impedance, to determine how difficult they are to drive. To take these readings, I inserted the Ultimate Ears 'phones in my ears so that they had the correct acoustic loading.
The Ultimate Ears 18 Pros' impedance and electrical phase are shown in fig.1. The impedance meets the 21-ohm specification…
I walked home from Nicole and Natalie’s place late Sunday night, during the height of the blizzard. It was a stupid thing to do. Normally a pleasant five-minute walk, that short stretch from their place to mine turned into the most painful and unpleasant experience I’ve ever endured, the fierce wind shooting little daggers of ice into my face and covering my body in snow. Somewhere around the corner of Newark Avenue and Second Street, I thought about just giving up and dying in it. It was so pretty. When I finally made it home, panting uncontrollably and hoping I hadn’t caused some…
While high-priced equipment can easily acquire stature on grounds of outright performance and physical appearance, we critics have more admiration for genuine achievement at lower price levels. One such product was the all-triode SP8 preamplifier from Audio Research, launched back in 1982 and priced at $1400. This classically tasteful preamplifier came equipped with a medium-sensitivity phono equalizer and the usual tape and line inputs.
In my review of the SP8 in the February 1983 edition of Hi-Fi News & Record Review, I described a topnotch performer that was equally adept at…
The use of two gain stages in series provides correct signal polarity, while a cathode-follower output confers wide bandwidth and low output impedance—in this case, a claimed 200 ohms. FETs are also used for interfacing and for constant-current duty.
In ARC's earlier preamplifier designs, the input section used a hardwired selector switch and rotary, track-type level controls. Adopting later practice from the more costly, remote-controllable Audio Research preamps, the manually operated LS8 uses a FET-switched attenuator chip for volume, hence the finite input headroom. The input…
Sidebar 1: Sound Quality Ratings
Longtime readers of my work in Stereophile, and especially in Hi-Fi News & Record Review, know my propensity for attempting to apply a numeric rating to a product's overall sound quality. Some feel that I should keep these numbers to myself and simply describe their value in the subjective language of sound quality. However, overwhelming feedback indicates that readers value the ratings as a more accurate gauge than words alone. In the light of advancing performances, the original 0–10 scale has become open-ended. As a rough guide, the finest…
Sidebar 2: Associated Equipment
Analog source: Linn LP12 turntable with Lingo power supply, Naim ARO tonearm, Koetsu RS11 phono cartridge.
CD players: Krell KPS-20i and KPS-25s.
Preamplification: Conrad-Johnson Premier Fifteen phono equalizer, ART, Premier Sixteen, PV102/l; Audio Research LS7; Audio Synthesis Passion passive controller.
Power amplifiers: Cary 300SE LX20, Audio Research VT50, Krell FPB 650.
Loudspeakers: Wilson Audio WITT II, Quad ESL-63, Sonus Faber Electa Amator II, Cadence (India) Anina.
Cables: Siltech, van den Hul, Transparent.—Martin Colloms
Sidebar 3: Measurements
Generally, the engineering design of Audio Research products is beyond reproach; the LS8's very good lab results for response flatness, distortion, and noise hardly came as a surprise. There is hardly any point in printing a frequency-response graph that is perfect from 10Hz to 30kHz, –0.5dB, at better than 5Hz and 45kHz, –3dB down, or better than 1Hz and 118kHz (a bit less than claimed, but of course these results are output-cable–dependent).
I did investigate the output impedance variation with frequency to explore the dynamic range of the feedback-…