Reference Series Model 105 (1977-79)

Model 105 was a landmark product - not just for KEF, but also for the loudspeaker industry as a whole. Physical form followed acoustical function in this radical looking system that set new standards for tonal accuracy and precise stereo imaging. Such was its performance and reputation that in its revised form it remained in production until 1987.
 
Continuing the lineage of KEF’s high-end loudspeakers that started with the K1 Monitor, Model 105 was a three-way system of modular design, allowing the enclosure of each unit to be optimised for its respective frequency operating range. The result was a smooth and continuous dispersion pattern that gave superior imaging not only in the central position, but over a wide listening area. 
 
The bass section comprised a 12 inch bextrene coned bass driver, housed in a 70 litre closed box enclosure, fed by a filter section that included a novel topology to convert the bass roll-off to a third order characteristic, allowing a low –3dB cut-off frequency but with useful attenuation of the subsonic frequencies typical of the analogue sources at the time. The B110 midrange and T52 high frequency drivers were housed in a separate, heavily damped, enclosure, which could be directed towards the listening position independently of the bass section.
 
The acoustic response was precisely tailored for a neutral tonal balance, assisted by the adoption of the newly derived Linkwitz-Riley fourth order crossover alignment, and to minimize the risk of driver damage due to amplifier clipping, an indicator light could be set to trigger at specific peak power levels. 
 
Specification: Model 105
System type: Three-way, floor standing
Enclosure type: Closed box
Size: 965 x 415 x 455 mm (38 x 16.3 x 17.9 inches)
Weight: 36kg (80 lb)
Input Impedance: 8 ohms
Rated maximum power: 200W programme
Amplifier Requirements: 40-200 watts per channel into 8 ohms
Frequency response: 38-22,000Hz +/-2dB at 2m on measuring axis
Sensitivity: 86dB at 1m for 1W, anechoic conditions
Crossover Frequencies: 400, 2500Hz
Maximum output: 107dB on programme peaks under typical listening conditions
Finishes:  Walnut
Grille: Black cloth
System: SP1059
Drive units: B300 bass unit (SP1060), B110 midrange unit (SP1057), T52 tweeter (SP1049)
Crossover: SP1062 (peak level indicator circuit), SP1100