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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…

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…

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…

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…

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

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-…

Description: Tubed line preamplifier with digitally controlled volume control, five inputs, and two outputs. Tube complement: four 6922 dual triodes. Maximum gain: 12.2dB. Input impedance: 50k ohms. Maximum input level: 3.5V. Input sensitivity: 500mV for a rated output of 2V. Frequency response: 0.5Hz–100kHz, ±0.5dB, 0.1Hz–250kHz, –3dB. Distortion: –80dB, or 0.01%.
Price: 1495 (1999); no longer available (2010). Approximate number of dealers: 65.
Manufacturer: Audio Research High Definition, Minnetonka, MN 55343-4424 (1999). Audio Research Corporation,…

The ideal rock singer/songwriter? Someone who addresses adult issues with all the passion of adolescence (than which, believe me, there is none more monomaniacal—there's no righteous indignation like a teenager's). Someone who can sing about him- or herself and strike the universal; someone who can tell a story of what the swells call "the human condition," or of some social injustice, in terms of how it affects a single life in all that…