KLH Model Five

 Acoustic Suspension Speaker System

The KLH Model Five represents our best efort to make the highest level of loudspeaker performance available in a system of reasonable size and cost. It combines very wide frequency range, low distoetion and exceptionally uniform response across the audible frequency range. It offers the greatest low frequency and power handling capabilities of all KLH bookshelf size speaker systems. And its high frequncy response and dispersion provide the impression of an open, completely unrestricted sound source, with fullmusical definition of even the most complex and demanding orchestral material.

The Model Five is a four-speaker, three-way system of acoustic suspension design, housed in a cabinet of oiled walnut measuring 26 inches by 13-¾ inches by 11-½ inches. It is finished on four sides, and may be used vertically or horizontally on the floor or wall. Its impedance is 8 ohms, allowing efficient power transfer from solid-state amplifiers. And its power demands (suggested minimum; 25 watts IHF music power per channel) are well within the capabilitles of good amplifiers of both tube and transistor design.

 The low frequency speaker is a 12-inch driver with heavy cone and magnet assemblies. Its cone is a critically controlled mixture of cotton and wood pulps, wool and asphalt. Like other KLH acoustic suspension speaker, it does not rely on the stiffness of a conventional outer cone suspension to control the motion of its cone at low frequencies.

Instead, it uses the acoustic stiffness of the air trapped within its tightly sealed cabinet to supply the necessary restoring force for the cone. This "air spring" is far more linear in action than the best mechanical speaker suspensions, and reinforces the cone's ability to make accurate axcursions over long distance to reproduce the lowest frequencies without distortion. Its low frequency harmonic distortion, the most critical factor in determining the usable bass response of a loudspeaker, remains minimal at the lowest frequencies and the highest listening levels ever likely to be called for in a living room. Its overall bass capabilities are greater than those of far lerger conventional speaker systems.

The two mid-range speakers are he same remarkable miniature, heavy magnet drivers used as full range units in the KLH Model Twenty-One radio and model Eleven phonograph. These speakers, with the highest ratio of magnet power to cone weight over built into a loudspeaker, are capable of far wider frequency coverage than they are called on to supply in the Model Five. Their use here over a limited frequency range helps to achieve a trully remarkable clarity and uniformity of response in the mid-range, and to supplement the excellent dispersion of high frequencies.

The high frequency speaker, also mounted in a sub-enclosure, is a 1-¾-inch direct radiator with a cone of critically shaped shell-like amterial. The high frequency response of the Model Five is greatly responsible for both its remarkable musical definition and the impression of an open, unrestircted sound source. High frequencies actually play a more important role than bass in achiving breadth and spaciousness of reproduced sound, and the Model Five's overall performance at high frequencies is equalled. In our experience only by the KLH Model Twelve, which uses the same mid- and high frequency drivers. The Model Five's capability for revealing without exaggeration, previously missing details of musical definition is best judged by listening to a good record with which you are throughly familiar. We believe you will be genuinely startlrd by the results of such a lest.

 The cones suspensions and other critical parts of all four speakers in the Model Five are designed, manufactured, and rigidly controlled by KLH. It also allows attention to the small details of construction that are at least as important as basic design principles in achieving a given and consistend level of performance. And it allows us to guarantee that any two Model Five all the production line will  match within 1-½ dB across the entire frequency range - a level of uniformity which can be promised, to our knowledge, by no other manufacturer.

To provide for a final choice by the listener of the relative balance of important segments of the frequency range, the Model Five is provided with two three-position switches that adjust the 2500 - 7000 cps and 7000 - 20,000 cps ranges. These switches permit far more precise and repeatable adjustments than do the simple variable resistors offered for high frequency adjustment of most multi-speaker systems.

The Model Five is constructed of ¾-inch plywood carefully finished with furniture grade walnut veneer. Its cabinet design is intended to make the system appear smaller and less obtrusive than speakers of equivalent size. The grille panel can be shapped out for cleaning or substitution of other grille materials.

Specifications:

Power Handling:  25 watts minimum

Nominal Impedance:  8 Ω

Dimensions (W x H x D):  13 ¾ x 26 x 11 ½ inches

Weight (unpacked):  44 lb