The SUB3

The SUB3 is a sub-woofer designed to work with the Chartwell LS3/5 and
LS3/5A from Graham Audio, but it is also applicable to other designs of
similar sensitivity and impedance. Designed by Derek Hughes, it employs a
novel bass loading technique to achieve extension down to 35Hz in a
compact enclosure.

They are supplied in pairs, and are designed to be placed near to the
rear wall, while the main loudspeakers remain in their usual ‘free space’
position. Output is via the front-facing reflex port.

There are connections on the rear for the input from the amplifier and
output to the main speakers. There is also provision for feet or spikes to
be fitted to the base of the cabinet. Being passive, there are no controls
to misadjust – the system is designed to be “plug and play”.

The crossover uses high quality components, including air-cored inductors
for zero saturation distortion and polypropylene capacitors. The system
crosses over at 100Hz, and in doing so, relieves the LS3/5 or LS3/5A of
energy frequencies below this point. This will allow the system to reach
greater replay volumes, providing there are adequate reserves in the
amplifier used.