The 25B and 35B subwoofers were variants of the 20B and 30B made specifically for the US market. Model 25B featured a downward firing 250mm (10”) bass driver in a reflex enclosure whereas Model 35B used an internally mounted 300mm (12”) driver in coupled cavity configuration with rear mounted ports.

 

Specification: Model 25B
System type: Active subwoofer
Enclosure type: Reflex
Dimensions (H x W x D): 460 x 360 x 360mm (18 x 14 x 14 inches)
Weight: 16.5kg (36.4 lbs)
Drive Unit: 250mm (10”) long throw
Amplifier: 100W
Frequency response: 38Hz to 150Hz +/-2.0dB
Maximum output: 111dB
Finish: Black Ash
System: SP3285
Drive Unit: B250 (SP1427)
Amplifier: SP2298 (120V)

 

Specification: Model 35B
System type: Active subwoofer
Enclosure type: Coupled cavity band pass
Dimensions (H x W x D): 460 x 407 x 407mm (18 x 16 x 16 inches)
Weight: 17.5kg (38.5 lbs)
Drive Unit: 300mm (12”) long throw
Amplifier: 80W (150W peak program)
Frequency response: 38Hz to 140Hz +/-2.0dB
Maximum output: 113dB
Finish: Black Ash
System: SP3286
Drive Unit: B300 (SP1428)
Amplifier: SP2248 (120V)

 

Download KEF Home Theatre Model 25B Installation Manual
Download KEF Home Theatre Model 35B Installation Manual