KLH Premier 81 Bookshelf speakers
In the 1960's, KLH was one of the best-known names in the high-fidelity world. KLH loudspeakers earned a reputation for exceptional sound at affordable prices, and the name was I also associated with the first high-fidelity portables and the first home tape recorder (open-reel) with Dolby B noise reduction.
Since 1980, the company's ownership has changed a couple of times, and for a number of years the KLH name almost disappeared from view in the hi-fi speaker market. Recently, however, a revitalized KLH has announced a series of home loudspeakers that promise a combination of value and performance not unlike that of the early KLH products.
KLH says its Premier Series is designed to provide the essential qualities of more costly speakers at affordable prices. The Premier 81, one of two bookshelf models in the line, is a vented two-way system with an 8-inch woofer crossing over at 1,300 Hz to a 1-inch soft-dome tweeter. The woofer has a 1.5-inch high-temperature voice coil and a polymer-fiber cone. The tweeter voice coil is wound on a Kapton form and cooled by ferrofluid.
The KLH 81 is finished on all sides and weighs a solid 22 pounds. The front edges are beveled, and the drivers are mounted flush with the front panel. The bass port is on the rear, as are the recessed gold-plated five-way binding-post connectors. A removable black cloth grille, on a wooden frame, is retained by plastic snaps.
We mounted the KLH 81 speakers on 26-inch stands, about 8 feet apart and 3 feet in front of a wall. Their averaged room response was very flat and smooth, especially above 300 Hz, where room-boundary effects were negligible. The output varied only +/-2.5 dB from 100 to 20,000 Hz. The combined woofer and port response spliced easily to the room response, resulting in a composite frequency response of + 5, - 2 dB from 30 to 20,000 Hz. (The maximum output occurred between 60 and 70 Hz). Although close-miked woofer measurements can give a misleading impression of a speaker's true bass capabilities, listening tests established that the KLH 81 could deliver useful, reasonably clean output as low as 32 Hz.
A quasi-anechoic MLS measurement of the axial frequency response showed an output variation akin to that obtained in the room measurement: +/-2.5 dB from 1,500 to 20,000 Hz, with a maximum of +3.5 dB at 1,200 Hz and a gentle decline to - 2 dB at 300 Hz. A ground-plane MLS measurement at 3 meters (which eliminated early floor reflections) gave generally similar results, with an overall variation of +/-4 dB from 300 to 20,000 Hz.
The tweeter's horizontal dispersion was typical of 1-inch dome radiators, with the response curves on-axis and 45 degrees off-axis beginning to diverge above 6,000 Hz; off-axis output was down 5 dB at 10,000 Hz and 14 dB at 20,000 Hz. Group delay varied less than 50 microseconds from 4,000 to 20,000 Hz, with an increase to 1.25 milliseconds at 50 Hz.
The KLH 81's impedance reached its low of just over 5 ohms at 150 Hz. It peaked to about 22 ohms at 25 and 75 Hz and to 15 ohms at 800 Hz. The speaker's impedance averaged between 10 and 15 ohms over most of the audio range.
The system's sensitivity measured 90 dB sound-pressure level (SPL) at 1 meter with a 2.83-volt pink-noise input. At that level, the woofer distortion was a uniform 0.7 to 0.9 percent from 80 to 1,300 Hz, increasing to 2 percent at 50 Hz and 7 percent at 20 Hz. The woofer cone reached its suspension limits at 100 Hz with a singlecycle input of 510 watts into its 7.5-ohm impedance at that frequency.
The KLH Premier 81 speakers sounded about as good as they measured, which is to say very good indeed. Their output was as smooth and extended as that of many speakers selling for several times their modest price, with only a slight upper-bass warmth to distinguish them from some speakers we have tested that cost in the range of $1,000 to $1,500 a pair.
It came as a pleasant surprise to find that the KLH 81's single 8-inch woofer was actually capable of reaching into the bottom musical octave. A 31.5-Hz sine wave from a test CD produced a room-filling output, clearly consisting mostly of the fundamental frequency. Though not as powerful as the bass we have heard from larger systems, it was real bass (this was also verified by our woofer distortion measurements).
When you combine these qualities with a handsomely finished cabinet and a modest price, it is clear that the KLH Premier 81 does honor to its heritage.
