In the world of audiophiles, some names are spoken with particular reverence. KLH Model Five is one of them. Released in the late 1960s, these speakers became a true legend, a symbol of the warm and detailed “American” sound of their time.
Decades have passed, and KLH has decided to revive the classic. The new version of the Model Five is not just a retro stylization. These are carefully modernized speakers that carefully preserve the soul of the original.
In this review, we'll listen to how this reincarnation of a legend sounds. We'll understand what remains of that very sound character and what modern technologies have added to its precision and power. This is a journey from the past to the present.
Pioneers of the closed-back headphones
The KLH Corporation was founded in 1957 in Cambridge, Massachusetts. One of its founding fathers was sound engineer and businessman Henry Kloss. By that time, he had already worked at Acoustic Research with inventor Edgar Wilcher and participated in the development of closed-back speakers.
Surprisingly, engineers learned how to use a closed volume to build speakers later than they invented the phase inverter. It took a long time to get the dynamic head to work with a closed box, because the elasticity of the air consumed a significant part of the diffuser's energy.
The pressure gradient could be reduced by radically increasing the volume of the enclosure, but there was little point in inventing another huge cabinet. Incidentally, the word “cabinet” is by no means a metaphor: high-end (for those times) speakers were really huge, and some people actually built them right into their wardrobe doors.
Vilchur was the first to realize that air springs should not be suppressed, but used to improve sound quality. Therefore, he made the suspension and centering washer of the speaker as soft and flexible as possible. Such a driver could hardly function on its own, but in a closed box, its membrane gained the necessary support.
In addition, it turned out that air is much better than any rubber or paper corrugation as a return spring. It does not age or wear out, but most importantly, it has high linearity of dynamic characteristics. To further improve damping, all that remained was to fill the enclosure with sound-absorbing material, and voilà—in 1954, the “acoustic suspension” design was born.
This is what Henry Kloss chose for the flagship speakers of his KLH brand. Why? Because as both an engineer and a businessman, he understood perfectly well that listeners were in dire need of a radical improvement in bass quality with relatively compact acoustics. True, a well-damped driver could not boast high sensitivity, but by the 1960s, amplifiers had already managed to flex their muscles and had made significant progress in the fight against distortion.
Flax and walnut
The original KLH Model Five speakers were produced from 1968 to 1977 and became one of the best-selling speakers in the United States during those years. Over time, new favorites appeared on the hi-fi scene, and KLH miraculously avoided falling into oblivion, becoming part of the Japanese company Kyocera. But in the end, the company was lucky: in 2017, it was acquired by another veteran of the American audio business, David Kelly.
He moved the company's headquarters to Indiana, where he began working intensively on a completely new line of speakers. Among them were many of the familiar narrow phase-inverter towers, but since last year, a remake of the famous Model Five has occupied a special place in the catalog.
Externally, the acoustics have remained virtually unchanged. The cabinets, 66 cm high and 35 cm wide, are made of 19 mm ultra-rigid MDF panels and finished with natural veneer. You can choose between West African mahogany or darker and more contrasting walnut. The speakers are hidden behind old-school fabric grilles, decorated with a cast zinc badge with the KLH logo, just like 54 years ago.
Linen fabric in different finishes varies in texture, but if desired, the desired screen can be ordered separately. The grilles are secured to the front panel with magnetic latches, while owners of the original version had to fiddle with Velcro fasteners.
To create the right sound field, the package includes steel podiums that not only raise the speakers above the floor but also tilt them back five degrees. The absence of a phase inverter also makes placement easier, and an attenuator is installed on the rear panel for precise room correction. With its help, you can press down the entire range above 400 Hz by one and a half or three decibels — a good way to adapt to noisy rooms.
Designer variation
I have no doubt that all the technical documentation for the original “fives” has been preserved, but the developers had the good sense not to make exact copies of half-century-old speakers. After all, over the decades, dynamic drivers have reached a completely different level of development and production, and it would be strange not to take advantage of this.
For example, the original tweeter diaphragm was a 1.75-inch paper cone, the woofers and two midrange drivers were pressed from thin, soft sheet metal, and their magnets were quite weak by today's standards.
The modern version of the KLH Model Five features a high-frequency driver with a one-inch aluminum diaphragm on a rubber suspension. The midrange and low-frequency drivers are still paper, although the speakers themselves are, of course, different. There is not much information about them, but they definitely have cast aluminum baskets and powerful ferrite magnets. The upgrade also made it possible to use one 4-inch midrange driver instead of two.
The crossover was also redesigned to accommodate the new drivers. It now uses coils on cores made of modern ferromagnets and Mylar capacitors.
The KLH Model Five is not just a new speaker, but a modern reinterpretation of a cult model from the past that once changed the perception of home audio. These speakers sound honest and natural: the music flows smoothly, without excessive sharpness or bass boost, revealing details that are often lost in other systems. They don't shout about their technology, they just make you want to listen to music over and over again — with pleasure, not with calculations of hertz and decibels. If you want sound that doesn't tire you out but draws you in, the Model Five is one of the best options available today.
More alive than ever
The speakers were tested in conjunction with the AMC XIA100se amplifier. Its output stages are built on MOSFET transistors, and the plasticity of the sound is reminiscent of tubes. Meanwhile, this integrated amplifier has plenty of power — 2 x 140 W (4 ohms), which is quite sufficient for speakers with a sensitivity of 87.5 dB in a free field. The source was a TEAC NT-505 network player, and the speaker cables were Analysis-Plus Oval 12.
The sound signature of the “acoustic suspension” made itself felt from the very first bars. When you listen to phase-inverter designs all the time, you simply stop realizing how multifaceted, relief-like, and tonally balanced the bass range can be. The low-quality 10-inch woofer, suspended, in essence, on 50 liters of air, further “thickened” by a voluminous sound absorber, is enviably energetic and truly very linear.
This is understandable, since the bass frequencies are not pulled toward the phase inverter's resonance frequency and do not fall behind it with a slope of 24 dB per octave. A closed box has its own specifics. The absence of a resonator tube provides a smoother decline (12 dB/oct.), but due to the complexity of lowering the resonance frequency, it usually starts a little earlier. The Model Five's frequency response ranges from 42 Hz to 20 kHz with an unevenness of 3 dB, and reaches 32 Hz at a level of -10 dB.
The low frequencies on Sia's album “Colour the Small One” were particularly impressive. In places, there are several different bass parts at once, and they are written with richness and soul. The speakers played them densely and diversely, with a quick attack, but without excessive pressure on the higher frequencies of the recording.
I deliberately began my story about deliberately old-school acoustics with a modern progressive album that has nothing to do with jazz or rock ‘n’ roll. I really wanted to emphasize that in the modern musical context, with its exaggerated bass, acoustic suspension is even more relevant than it was 50 years ago.
SACD releases (Esoteric) by Ella Fitzgerald and John Coltrane, as well as Elvis Presley's From Elvis in Memphis and the Rolling Stones' Goats Head Soup, helped bring the speakers back to their historical youth.
What can I say, the general public was deprived of such clear high frequencies in those years, but they definitely dreamed of them. The high resolution of the new tweeter allows you to create a voluminous, well-developed musical scene, but does not overload the sound with sibilants and percussion.
The midrange sounds energetic and expressive. You can feel that the small 4-inch diffuser, combined with a powerful magnetic system, easily keeps up with the tweeter. In addition, its small diameter helps to achieve wide spatial coverage (140-degree horizontal dispersion). Occasionally, however, there is a feeling that the assertiveness of the vocals slightly obscures the subtle intonations, but the guitars are fantastic!
Ultimately, the new KLH Model Five is not just a nostalgic release. They skillfully combine the spirit of the original speakers with modern technology. The sound is warm, detailed, and very musical — just what the old models were valued for.
These speakers won't scream for attention with intrusive brightness. Their strength lies in their balance and ability to play a wide variety of genres tirelessly. They will reveal a jazz record and a new high-resolution rock album equally well.
For those looking for speakers with character and history, the Model Five is an excellent choice. This is a case where the revival of a legend has been surprisingly successful. The speakers deliver a lively, engaging sound that is simply a pleasure to listen to.
