In the early 1970s KEF invested heavily in digital technology to assist the design and manufacture of loudspeakers. Using computers to control acoustic measurements allowed data to be stored in a form that significantly aided the design process as well as forming the basis of an advanced production quality control system. The first loudspeaker to benefit from this was the first of the new Reference Series, the Model 104.

 

Model 104 was an 8 inch two-way system with an passive radiator augmenting the low frequency response, a format that was developed previously for the Cadenza system. The B200 bextrene coned bass driver for the 104 had a short coil/long gap magnet system for low distortion and the system included a three position acoustic contour control, which allowed +/-2dB of midrange level adjustment.

 

In 1976 the system was updated into the 104aB, where aB stood for ‘acoustic butterworth’, relating to the shape of the acoustic response of the midrange and treble drivers in the crossover region. Perfect integration of the units will only happen if the acoustic responses of the two units conform to a precise characteristic. Previously, crossover filters had been designed primarily on the basis of the electrical response of the filter but, in reality, the acoustic roll-off is also a function of the natural roll-off of the driver response. By considering the filter and driver as a combined system the filter response can then be optimised to give the precise acoustic roll-off necessary for perfect integration.

 

The Model 104aB Kit was available to those who chose to build the Model 104aB components into their own enclosures. Supplied with drive units ready assembled onto the lacquer finished baffle with all electrical connections made.

 

During the early and mid 1970s KEF was the first company to utilise computers in the design and analysis of loudspeakers. The design process that flowed from this was termed ‘Total System Design’ where the final performance of the speaker was seen as the combination of drivers, cabinet and crossover all working together to produce the target acoustic response, with computers being used throughout for simulations and analysis. The Corelli, Calinda and Cantata represented the first application of this methodology in the mid priced sector.

 

Cantata was a three way closed box design using the famous B139 ‘racetrack’ bass driver, a new version of the B110 bass/midrange unit and the new T52 tweeter. In the Cantata system the driver layout allowed a slim frontal aspect ratio, demonstrating how industrial design was developing through the 1970s.

 

The Cantata Kit was available to those who chose to build the Cantata components into their own enclosures. Supplied with drive units ready assembled onto the lacquer finished baffle with all electrical connections made.

 

Specification: 104aB KIT
System type: Two-way, stand-mount
Enclosure type: Passive radiator
Size: 388 x 310 x 212 mm (15.25 x 12.2 x 8.36 inches)
Weight: 14kg (31 lb) per pair packed
Input Impedance: 8 ohms
Rated maximum power: 100W programme
Amplifier Requirements: 15-100 watts per channel into 8 ohms
System resonance: 35Hz, mechanical reflex
Frequency range: 30-30,000Hz
Frequency response: 50-20,000Hz +/-2dB
Sensitivity: 12.5 watts for 96dB at 1m and 400Hz in anechoic conditions
Crossover Frequency: 3000Hz
System: SP1109
Drive units: B200 bass unit (SP1039), BD139 passive radiator (SP1042), T27 tweeter (SP1032)
Crossover: SP1065

 

Specification: Cantata KIT
System type: Three-way, floor standing
Enclosure type: Closed box
Size: 62.2 x 31.2 x 34.8cm (24.5 x 12.3 x 13.7 inches)
Weight: 24kg (52.8 lb) per pair packed
Input Impedance: 8 ohms
Rated maximum power: 150W programme
Amplifier Requirements: 15-150 watts per channel into 8 ohms
System resonance: 38Hz, Q=0.7
Frequency range: 35-20,000Hz +/-3dB
Sensitivity: 8 watts for 96dB at 1m and 400Hz in anechoic conditions
Crossover Frequencies: 250 and 3000Hz
System: SP1110
Drive units: B139 bass unit (SP1044), B110 bass unit (SP1057), T52 tweeter (SP1049)
Crossover: SP1115 and SP1116