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”.
| System | 4th order bandpass |
| Finish | Real wood veneer |
| Dimensions (w/h/d) | 30cm by 30cm by 34cm |
| Frequency response | 35Hz to 100Hz |
| Nominal impedance | 8Ω |
| Sensitivity | 84dB SPL (2.83V, 1m) |
| Recommended amplifier power | 30 to 80 watts unclipped programme |
| Connections | Gold-plated binding posts |
