Chartwell Sub 6

Chartwell Sub 6 – a passive subwoofer designed to complete the BBC monitor system

Derek Hughes' solution for the LS3/5 and LS3/5A

Designed by Derek Hughes specifically for the Graham Audio LS3/5 and LS3/5A, the Chartwell Sub 6 is a passive subwoofer — no built-in amplifier, no separate power supply. Your existing amplifier drives both the subwoofer and the main speakers. Consequently, the signal path stays pure and coherent, without additional active components altering the character of the BBC monitors. Placed directly beneath the main speakers, the Sub 6 integrates seamlessly into any existing setup.

Passive crossover with audiophile-grade components

The crossover operates at 120 Hz, using air core inductors for zero saturation distortion and polypropylene capacitors for stable performance across the musical range. Furthermore, crossing over at 120 Hz relieves the LS3/5 of low-frequency signal content, thereby increasing the combined power handling of the system. As a result, the main speakers can be driven harder without distortion — and overall dynamic headroom improves measurably.

Front-firing port and practical connectivity

A front-facing reflex port allows wall-proximity placement without compromising bass output. On the rear panel, a single input accepts the signal from the amplifier and a single output passes it on to the main speakers. Since the Sub 6 sits entirely within the existing signal path, no additional cabling or active components are required. Feet or spikes can be fitted into the base of the cabinet, allowing acoustic isolation from the supporting surface.

Compatible beyond the LS3/5 family

Although optimised for the LS3/5 and LS3/5A, the Sub 6 also works with other loudspeakers of similar sensitivity and impedance. Moreover, the precision of Derek Hughes' crossover design ensures musical coherence regardless of the main speaker used. Above all, the Sub 6 adds bass depth without imposing its own character — the monitors remain the centre of the system.

Specifications

• Type: passive subwoofer
• Crossover frequency: 120 Hz
• Crossover components: air core inductors, polypropylene capacitors
• Port: front-firing reflex
• Connections: amplifier input, main speaker output
• Placement: beneath main speakers
• Feet/spikes: user-fittable
• Designer: Derek Hughes
• Origin: hand-built in Devon, England

Frequently asked questions about the Chartwell Sub 6

Why passive rather than active?

A passive subwoofer has no amplifier of its own — your existing amplifier handles everything. Since no additional active electronics enter the signal chain, the tonal character of the BBC monitors is fully preserved.

Does the Sub 6 work with speakers other than the LS3/5 and LS3/5A?

Yes — it is suitable for other loudspeakers of comparable sensitivity and impedance. Thanks to the careful crossover tuning by Derek Hughes, it integrates coherently with a wide range of compact high-quality monitors.

What does the 120 Hz crossover frequency do for the LS3/5?

By relieving the LS3/5 of signals below 120 Hz, the combined system power handling increases. Consequently, the main speakers can be driven louder without distortion — and the overall dynamic performance of the system improves noticeably.