KLH HISTORY
KLH Audio was established in 1957 by Henry Kloss, Malcolm Low & Josef Hofmann. Henry Kloss first made his name as part of Acoustic Research with the introduction of the AR-1 and its patented acoustic suspension system that revolutionized the high-fidelity industry. Henry Kloss later left Acoustic Research to start KLH and immediately began marketing his own acoustic suspension loudspeaker designs.
KLH marketed their own family of loudspeakers throughout the 1960’s and 1970’s – highlighted by the well-known Model Five as well as the very highly regarded Model Nine electrostatic loudspeaker. The company later expanded into FM radio with their very successful Model Eight and soon began building their own turntables such as the Model 11 & Model 23. Henry Kloss was a true trailblazer in the world of audio and audio electronics.
ACOUSTIC SUSPENSION
First introduced in 1954, the acoustic suspension principle has long been regarded as the most accurate of all the loudspeaker designs available. Edgar Villchur and Henry Kloss worked together to bring the original Acoustic Research AR-1, and several later models, including the well-known AR-3, to market. Several brands, including KLH, would adopt the acoustic suspension principle and use it in their loudspeakers designs for many years to come. Acoustic suspension dominated the speaker market well into the 1970’s.
In an acoustic suspension design, the volume of air inside the enclosure serves as a cushion of air, or air spring, to provide a restoring force for the woofer cone. The air inside the enclosure essentially becomes the dominant part of the woofer’s suspension. Since the volume of air inside the enclosure is more linear than the mechanical parts of the woofer’s suspension, this enables the woofer’s diaphragm to move in a more linear fashion. This enables the driver to operate at higher excursions with less distortion than more traditional bass-reflex type systems. Acoustic suspension systems are regarded all over the world for their greater accuracy, tighter bass transients and exceptional bass resolution and texture.
MODEL SEVEN DESIGN
The KLH Model Seven is a 3-way design featuring a wide-baffle enclosure, high-volume displacement 13” woofer, 5” dedicated midrange, and 1” dome tweeter. The wide baffle enclosure ensures the sound is focused primarily in front of the loudspeakers and minimizes the amount of sound that wraps around and behind the loudspeaker. This reduces sound reflecting off the nearby rear and side walls of the listening room that compromise precision in imaging and soundstage.
Larger diameter woofers generate cleaner extended deep bass than smaller woofers. The larger cone area and suspension parts of the Model Seven woofer allow for a much larger volume displacement. It’s the high-volume displacement woofer in combination with the acoustic suspension principle that results in tighter bass transients and cleaner, better-defined, bass extension. In the car world there’s an old saying “there’s no replacement for displacement”. The same is true for acoustics and loudspeakers.
The dedicated 5” midrange is housed in its own internal enclosure. It’s the midrange driver’s responsibility to reproduce the most significant, middle part, of the audio spectrum. This portion of the audio band contains the vocals and musical instrument fundamentals which are most familiar to the human ear; and where accuracy, or inaccuracies, are most easily detected. In a three-way design a dedicated midrange means the driver can be optimized for this specific purpose since it doesn’t have the additional burden of reproducing lower & higher frequencies in the audio band. This results in truly remarkable clarity of vocals & instruments with less distortion.
