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Unity Audio Signature 3 Measurements

Sidebar 2: Measurements

Other than impedance, all acoustic measurements were made with the DRA Labs MLSSA system and a calibrated B&K/DPA 4006 microphone. To minimize reflections from the test setup, the measuring microphone is flush-mounted inside the end of a long tube. Reflections of the speaker's sound from the mike-stand hardware will be sufficiently delayed not to affect the measurement.

The Unity Audio's sensitivity was about average at a calculated 86dB/2.83V/m. As stated by Kathy Grost, the Unity Signature 3 does have a flat impedance with frequency, as can be seen…

Unity Audio Signature 3 Specifications

Sidebar 3: Specifications

Description: Two-way, three-driver, sealed-box, floorstanding loudspeaker. Drive-units: two 6.5" polypropylene-cone woofers, one front-firing, one rear; one 1" cermaic-coated silk-dome tweeter. Frequency response: 39Hz–20kHz, ±2dB. Sensitivity: 86dB/W/m. Nominal impedance: 5 ohms. Maximum power handling: 300W.
Dimensions: 9.25" W by 4" D by 38" H. Weight: 33 lbs.
Standard finishes: walnut, black oak. Special finishes, $250 extra: piano black, curly or birdseye maple, rosewood, two-tone mixes.
Serial numbers of units reviewed: CA002196/97, first pair;…

A Unique KEF Event

All photographs by Lily Szabo Photography and used with permission

Thursday February 13 was a day most of us in New York would have preferred to stay indoors. With 10” of snow falling since the night before, the Stereophile office closed, the roads in my neighborhood impassable, and public transport iffy at best, I really didn’t want to make the trek into Manhattan. But I did and was glad to have done so. English loudspeaker manufacturer KEF, represented by a team led by the company's brand ambassador Johan Coorg (above right), was promoting a unique event for the press at MSR Studios on…

Recording of March 2014: <I>Concerts: Bregenz München</I>

Keith Jarrett: Concerts: Bregenz München
Keith Jarrett, piano
ECM 1227–29 (3 CDs; also available as 24/96 files from HDTracks). 1982/2013. Manfred Eicher, prod.; Martin Wieland, eng. ADD. TT: 2:30:19
Performance *****
Sonics ****½

Keith Jarrett's gift for brilliant invention is apparently inexhaustible throughout both of these concerts, recorded five days apart in spring 1981. The combinations of lyricism, literally foot-stomping gospel, chordings and voicings alternately sumptuously lush and astringently lean, and unexpected musical destinations reached in surprising ways…

The Purpose of Music?

Way back when, I met this maenad woman at Caffe Reggio in Greenwich Village and told her I was an artist. She told me she was an art collector and invited me to her loft to see her collection. While she was showing me an impressive assortment of African and contemporary art, she was dropping names: William Burroughs, Bob Marley, John Cage, etc. Hmmm . . . really? I spoke up. "Oh, I love John Cage. What was he like?"

She told me that Cage picked her up one day to go to an art party in the Hamptons. When they arrived, he said he needed her help putting batteries in a box full of transistor…

Audeze LCD-X headphones

I well remember my first "real" headphones: a pair of Koss Pro4AAs that I bought back in 1970. The Kosses were relatively expensive, but, like headphones today, they allowed an audiophile with limited cash to get a taste of high-end sound that was not possible with a speaker-based system. I bought the Pro4AAs because I had become fascinated with how the images of the instruments and singers were strung along a line between my ears inside my head. It seemed so much more intimate—a more direct connection with the music—than playback through loudspeakers.

And in those early days of recording…

Audeze LCD-X headphones Page 2

A track I played during my 2013 presentations at audio shows and audiophile-society meetings was Eriks Esenvalds' O Salutaris Hostia, from the album A Drop in the Ocean, by the Portland State Chamber Choir conducted by Ethan Sperry (16-bit/44.1kHz master file for CD, PDK-C-01). I had mastered this CD for Stereophile's Erick Lichte, who had both edited the recording and produced some of the sessions. Massed voices are very difficult for audio systems to reproduce, because the spectrally rich content is sensitive to intermodulation distortion. This can be particularly problematic with…

Audeze LCD-X headphones Specifications

Sidebar 1: Specifications

Description: Circumaural (over-the-ear) headphones with planar-magnetic drive-units using neodymium magnets, and earpads of premium lambskin leather or leather-free, "microsuede" fabric. Supplied accessories: ADZ6SE cable (single-ended ¼" TRS to 2x4-pin mini XLR), ADZ6B4 cable (balanced 4-pin XLR to 2x4-pin mini XLR), ¼"-to-1/8" adapter, SKB travel case.
Cable length: 94" (2.5m). Weight: 37.5 oz. (600gm).
Serial number of unit reviewed: 7454038.
Price: $1699. Approximate number of dealers: >30.
Manufacturer: Audeze LLC,10725 Ellis Avenue, Unit…

Audeze LCD-X headphones Associated Equipment

Sidebar 2: Associated Equipment

Digital Sources: Astell&Kern AK100 portable media player; Apple 2.7GHz i7 Mac mini laptop running OS10.7.5, iTunes 10, Pure Music 1.89, Audirvana Plus 1.5.10, JRiver Media Center 19 for Mac; Shuttle PC with Lynx AES16 soundcard & dual-core AMD Athlon processor running Windows 7, Adobe Audition 3.0; Arcam rBlink Bluetooth D/A converter; Auralic Vega D/A converter.
Headphone Amplifiers: HeadRoom BlockHead, Benchmark DAC1, ASUS Xonar Essence One Muses Edition, Meridian Prime with Prime power supply.
Headphones: Sennheiser HD650 & HD800.…

Audeze LCD-X headphones Measurements

Sidebar 3: Measurements

I don't measure headphone acoustic responses, as this requires a dummy-head-and-microphone system: see Keith Howard's article on this subject in the August 2008 issue. In addition, as Keith wrote, deciding what, precisely, is the optimal frequency response for a pair of headphones is neither obvious nor trivial.

I used Stereophile's vintage Audio Precision System One to measure the Audeze LCD-X's impedance and electrical phase (fig.1). The solid trace in this graph shows the impedance magnitude with the headphones mounted on my head facing my ears. The…