What is stereo?




There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.




H.H. Scott '59





KEF Model 101

 Ever since the Celeste was released in 1962 KEF has been noted for producing high performance compact loudspeakers. The Cresta, released in 1967, set new standards with the newly developed B110 and T27 drivers that were later to be adopted in the world famous BBC designed LS3/5A broadcast monitor.
 KEF Model 101 is a truly outstanding product of modern loudspeaker technology. Although small in overall dimensions and simple appearance. Model 101 contains one of the most advanced sound reproduction systems ever developed and achieves a standard of acoustic performance superior to that of many for larger loudspeakers.
Model 101 is a loudspeakers of Reference quality which will satisfy the professional user and enthusiast whose amplifier and related equipment are of the highest standard, but who require small, unobtrusive loudspeakers.
Model 101 offers many advantages over larger models where space is restricted as the systems are easily located to give excellent tonal balance and sharp,clear stereo images. Novel and precise production methods guarantee the frequency response within fine limits  resulting in stereo reproduction of outstanding perspective and sharpness.

Model 101 combined the T27 tweeter with the SP1057 version of the B110 in a 6.7 litre closed box. The system was fully overload protected by the S-Stop system, included mechanical decoupling of the bass driver to minimize colouration and each pair were acoustically matched to within 0.5dB. The result was a system with accurate tonal balance and detailed stereo imaging - being suitable for use with the best electronics - and able to fit unobtrusively into the listening room.

Features
Flat frequency response to 90 Hz (-10 dB at 47 Hz)
Two way system with minimum interunit time deley
Pairing of systems guarantees sensitivity and frequency response match to within 0,5 dB
Fully protected against fault conditions when used with amplifiers up to 100 watts
Electronic protection -S-Stop protects against overload and fault conditions

 The laws  of physics dictate that a small enclosure must either give less bass or have lower efficiency. To achieve a balance response in the design of Model 101, KEF use a tonal system design approach so that the drive units, filter networks and enclosures are developed together to achieve the broadcast band width with the optimum efficiency.
The close tolerances needed to realise the full potential of the design are maintained in production by a unique matching procedure so that every pair of Model 101's is matched in frequency response to within 1dB of the original laboratory prototypes.
The widespread use of high powered amplifiers which can deliver the full dynamic range captured with modern recording techniques, has made it necessary to protect loudspeakers against accidental overload. In Model 101 a self-powered electronic circuit called S-Stop, protects the loudspeakers from the effects of overload and automatically re-connects the full input signal to the system only when the overload is removed.
To allow the sound to reach the listener directly without troublesome reflections from walls, floor or ceiling the drive units are arranged within the 7 litre enclosure so that the full frequency response is enjoyed when the loudspeakers are positioned approximately 75 mm from the floor.
An optional stand, the ULS 20, allows the speaker to be conveniently and elegantly converted to a free standing system.

Specification: Model 101 
System type:  Two-way, bookshelf/stand-mount
Enclosure type:  Closed box
Input Impedance:  8 ohms
Rated maximum power:  100 W programme
Amplifier Requirements:  20 - 100 watts per channel into 8 ohms
Frequency response:  90 - 30,000 Hz ±2 dB at 2m on measuring axis (-10dB at 47Hz and 40kHz)
Sensitivity:  81 dB at 1m for a pink noise input of 1W
Distortion (Measured at 1m on measuring axis at mean spl of 90 dB, anechoic conditions):
Second Harmonic : less than 1% from 120 Hz to 20 kHz
Third Harmonic : less than 1% from 70 Hz to 20 kHz
Directional Characteristics:
Horizontal : within ±2 dB of axial response up to 20 kHz for ±20°
Vertical : within ±2 dB of axial response up to 20 kHz for ±5°
Crossover Frequencies:  400, 2500 Hz
Maximum output:  100 dB on programme peaks under typical listening conditions
Finishes:  Walnut, teak, rosewood and black ash veneers
Grille:  Black cloth
Size:  340 x 180 x 190 mm (13.4 x 7.1 x 7.5 inches)
Weight:  5.6 kg (12.3 lb)
System:  SP1122
Drive units:  B110 bass/midrange unit (SP1057), T27 tweeter (SP1032)
Crossover:  SP1123 and SP1124 (SP2010 from 1983)


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