Concord IV (1980-82) Celeste IV (1980-82)

The Celeste IV and Concord IV were distinctive for their industrial design, the all-round black grille cloth and matching ULS 40 single pedestal stand allowing them to stand out from the conventional square wooden boxes of the time.
 
Concord IV was one of the first ‘two and a half way’ designs – two 8” bass drivers being operated vertically in line at low frequencies. This arrangement improves power handling and reduces distortion at low frequencies. The response of the lower unit is progressively reduced as the frequency rises so that only the upper unit is radiating in the crossover region. By this means it is possible to retain the advantage of twin drivers at the low end of the range without the phase interference effects usually associated with multiple drive units.
 
The mark IV versions were different from the mark IIIs by virtue of the moulded plinth and top caps and a wide selection of coloured grille cloths.
 
The B200 bass drivers for the Celeste III/IV and Concord III/IV featured a new three-sided chassis specifically designed to be mechanically isolated from the cabinet – the first example of driver decoupling in the KEF range. They were also the first KEF bass drivers to use a paper diaphragm – by this time paper diaphragms were being manufactured with good consistency and the lower moving mass contributed to the high sensitivity target for these systems.
 
Specification: Concord IV
System Type: 2½-way, stand-mount
Enclosure type: Closed box
Size: 68 x 28 x 31.5cm (26.75x 11 x 12.4 inches)
Weight: 14kg (31 lb)
Input Impedance: 8 ohms
Rated maximum power: 100W programme
Amplifier Requirements: 10-100 watts per channel into 8 ohms
System resonance: 68Hz, Q=0.8
Frequency response: 60-20,000Hz +/-3dB
Sensitivity: 87dB spl at 1m for pink noise input of 1W
Maximum output: 107dB spl on programme peaks under typical listening conditions
Finishes:  Black or brown plinth and top
Grille: Black or brown grille fabric as appropriate. Beige, blue, red, green or grey available as optional accessories
System: SP1146
Drive units: 2 x B200 bass unit (SP1069), T33 tweeter (SP1068)
Crossover: SP1112
System: SP1146
Drive units: 2 x B200 bass unit (SP1069), T33 Tweeter (SP1074)
Crossover: SP1137
 
Specification: Celeste IV
System Type: Two-way, bookshelf/stand-mount
Enclosure type: Closed box
Size: 52.4 x 26.5 x 23cm (20.6 x 10.5 x 9 inches)
Weight: 8.1kg (18 lb)
Input Impedance: 8 ohms
Rated maximum power: 50W programme
Amplifier Requirements: 10-50 watts per channel into 8 ohms
System resonance: 68Hz, Q=0.7
Frequency response: 70-20,000Hz +/-3dB
Sensitivity: 86dB spl at 1m for pink noise input of 1W
Maximum output: 103dB spl on programme peaks under typical listening conditions
Finishes:  Black or brown plinth and top
Grille: Black or brown grille fabric as appropriate. Beige, blue, red, green or grey available as optional accessories
System: SP1145
Drive units: B200 bass unit (SP1070), T33 tweeter (SP1068)
Crossover: SP1108
System: SP1145
Drive units: B200 bass unit (SP1070), T33 tweeter (SP1074).
Crossover: SP1136