KLH Model Five loudspeaker

In May of 2019, I heard about a promising jazz vinyl and hi-fi estate sale happening on New York’s Upper East Side. Little did I know then what treasures the dig would yield.

Jazz Record Center’s Fred Cohen had called from the UES apartment, the former residence of late CBS Records and Sony Entertainment mastering engineer Harry N. Fein. Fred said, “The records are kind of beat, but the apartment is jammed with tape decks, turntables, cartridges, tubes, midcentury modern furniture—get up here.”

I called NYC turntable technician Mike Trei, who’s always up for a dig. Upon picking me up from my Greenwich Village pad in his pearl-black 1991 Mercedes, we zoomed uptown on Park Avenue. Well past Grand Central Station, we found the address on a quiet residential block.

At the doorway to the apartment, two muscled Russians were removing a ratty red velvet couch. We squeezed past them into a tiny living room. Books were strewn everywhere. A window sucked in hot, sticky air. A Zenith Seville console stereo, a crusty BSR McDonald turntable, and a ’60s-era Ampex Model AG-350-2 ½” tape machine stood sentry. Where were the records and other audio booty Fred spoke of?

Mike found a side door, jammed shut. We applied two-shoulder pressure and stumbled our way in. The 10′ × 6′ space—Fein’s secret workshop—was a time traveler’s dream of audio exotica.

Dixieland, swing, comedy, and vocal albums lined an in-wall case. Fein’s CBS mastering work was represented: Grachan Moncur III & The Jazz Composer’s Orchestra’s Echoes of Prayer, The Billie Holiday Story Volume II, and Jingle Bell Jazz. A Teac SX-3300 reel-to-reel deck sat on the floor. I pulled open a drawer crammed with Fairchild 225A mono, GE VR-1000, and Shure V15 cartridges. A closet produced a Scott Stereomaster 299-f integrated amp and a slate-gray, Streamline Moderne–looking Fairchild Model 202 tonearm complete with three Fairchild mono carts in turret headshells. Wedged into the back of the closet, their chunky cabinets faded and scratched, grilles seemingly blanched yellow by the sun, was a pair of vintage KLH Model Five loudspeakers.

Produced between 1968 and 1977, the KLH Model Five—like its siblings Models Six and Seventeen—was one of the most popular American loudspeakers ever.

KLH Research and Development Corporation was founded in 1957 by Henry Kloss, Malcolm Low, and Joseph Anton Hofmann. As John Atkinson wrote in 40 years of Stereophile: The Hot 100 Products, “The late Henry Kloss had the Midas touch: whatever his fancy alighted on turned into sonic gold.”

At KLH, Kloss developed the Model Eight FM table-top radio, the Model Nine electrostatic loudspeaker, the Model Eleven record player, and the first reel-to-reel tape recorder to include Dolby noise reduction: the Model Forty. Kloss also founded Advent Corporation (1967), Kloss Video Corporation (1977), Cambridge SoundWorks (1988), and in 2000, Tivoli Audio. And three years before KLH was established, Kloss and inventor/teacher Edgar Villchur launched Acoustic Research, Inc. (“AR”), which mass produced the country’s first sealed-box, acoustic suspension loudspeaker (the AR-1) and first suspended turntable (the AR XA), both affordably priced.

Like Acoustic Research’s popular AR-3a loudspeaker, the original KLH Model Five produced clean, tight bass owing to its acoustic suspension design, a departure from the then- (and now-) ubiquitous bass reflex designs. The Model Five included a 1.75″ pulp-paper tweeter, dual 4″ cone midrange drivers, and a 10″ paper-cone woofer mounted to the front baffle of a sealed plywood cabinet weighing 54lb. Reported impedance was 8 ohms.

KLH went kaput when its Japanese owner, Kyocera Ltd., terminated production of the legacy brand in 1989. Nearly 30 years later, in 2017, former Klipsch global sales president and Voxx Electronics executive David Kelley purchased KLH. Kelley relocated KLH HQ to Noblesville, Indiana, and relaunched the company in late 2018 with no fewer than 30 new loudspeaker models.

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The New Model Five
“We started development of the new Model Five two years ago,” KLH chief designer Kerry Geist wrote in an email. “Development was put on hold in early 2020 due to the pandemic, … but the desire was always there to bring back some of the better-known KLH models.”

The revived Model Five shares the original’s cabinet dimensions; three-way, acoustic suspension design (but with just one midrange driver, not two); and vintage-looking grille (a Stonewash Linen grille is available at $199/pair) with new drivers and crossover. KLH retained the zinc logo affixed to the speaker’s grille, and the price is still affordable ($1998/pair), but this isn’t Henry Kloss’s Model Five.

“We wanted to pay tribute to the original Model Five,” Geist told me, “but the goal was never to replicate the sound of the original. I looked at it from the standpoint of how the Model Five, with its acoustic suspension design, would be conceived and designed today. However, a 10″ pulp-paper woofer, mounted in the exact same cabinet dimensions and internal volume as the original, will ensure some amount of performance commonality. [But] transducer design (and testing) has come a long way in 50 years, and that translates to much better overall performance.”

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Manufactured in China, the Model Five employs a 1″ aluminum-dome high-frequency driver with soft-rubber suspension; a 4″ pulp-paper cone midrange driver, and a 10″ pulp-paper cone woofer driver. The mid- and low-frequency drivers utilize reverse-roll rubber suspensions and nonresonant, die-cast aluminum frames. The 13.75″ wide, 26″ high, 11.5″ deep cabinet is constructed of structurally reinforced ¾” MDF and weighs 44lb. The M5 is rated at 6 ohms nominal impedance with an in-room sensitivity of 90.5dB/2.83V/m. (The free-field sensitivity is 87.5dB/2.83V/m.) Each KLH Five comes with its own powder-coated, 8″ high, 14-gauge steel, 5°-slant riser base for the “proper angle to ensure the best vertical coverage for all listening positions.” Two finishes are available: English Walnut and West African Mahogany.

In addition to upgrading its drivers, Geist overhauled the M5’s crossover, a 13-component network that uses iron-core inductors and Mylar capacitors. “The crossover is all 2nd order, 12dB/octave,” Geist explained. “The low-pass woofer and high-pass midrange cross over at about 380Hz, low-pass midrange and high-pass tweeter at 2850Hz. The crossover is comprised of four inductors, four capacitors, [and] five resistors. Three of the resistors are used in the attenuation circuit for the switch located on the back panel.”

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Taking different-sized rooms and varying acoustics into consideration, Geist incorporated a three-position attenuator switch (marked “LO, MID, HI”) on the M5’s backside (above a pair of gold-plated binding posts), a holdover from the original M5—sort of.

“The switch attenuates/decreases output above 400Hz,” Geist explained. “I’m not a huge fan of attenuators on loudspeakers because of the affect they have on voicing of the loudspeaker. So, I repurposed the attenuator switch to deal with difficult room acoustics. The amount of attenuation is relatively small (0, –1.5dB, –3dB), over a broad frequency range. The idea is to pull some excess energy out of an overly bright listening room.”

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