Windsor Duke

The Windsor Duke is equipped with an 8” woofer, purposely-developed together with a 28mm textile dome tweeter, to perform seamlessly in a classic bookshelf / monitor styled cabinet.

The drive units have all been engineered from the ground up, using cast alloy components, yet retaining the essential character through the use of new woven Polypropylene cones and glass-fibre voice coils.

The cabinet work is, as you would expect from a product bearing the Castle name, first class. The hand-selected, book-matched pairs of veneers are sourced from the original suppliers to ensure continuity in the Castle legacy. Our dedicated ‘hand – finished’ team is trained to deliver the highest quality ‘furniture – grade’ finishes and build. No two pairs are the same!

Made in the UK

Echoing the origins of the brand that was established in 1973; the speakers are hand built and hand finished, by our loudspeaker production experts, in England.

Windsor Highs

The tweeter follows the classical formula of a high-consistency exposed polyester dome, with a pressure equalised Ferrite magnet system and a stable metal front plate. No Ferrofluid is used in the tweeter in order to guarantee the highest possible dynamic range. This also keeps the resonant frequency below 800Hz, for optimum performance.

A Royal Weave

The Polypropylene used in the cones is precision cut into thin strips, woven back into a sort of fabric and comes together again to form a solid foil. This foil gets pressed into the final shape and then cut to size. This helps to minimise resonances – the result of which is a much – desired, flatter response curve

Regal Magnetics

Improved openness of the midrange performance

Regal Magnetics

The magnet system in the Castle Windsor Series includes an aluminium compensation ring. This ring helps minimise the variation of the impedance during the operation of the drive unit. As a result, the harmonic and intermodulation distortion values are reduced, for improved openness of the midrange performance.

A Voice Coil of the Upper Class

Maintaining purity of signal

A Voice Coil of the Upper Class

The voice coils are made out of a glass fibre, bonded with high-temperature resin. The stiffness and overall rigidity of this material is very close to that of aluminium. It maintains purity of signal, by its very design.

Built Like a Castle

The main cabinet structure uses dual-layer MDF panels separated by a flexible, but thin layer of specially engineered – acoustic glue. This glue is purposely developed to dampen resonance in the critical midrange of the dual-layer panels. In order to achieve the optimum rigidity at lower frequencies, point – to – point bracing was used. The result is a quiet cabinet, without prominent peaks, and controlled output. Simple in theory but intricate in design and engineering – a trait of the Castle brand philosophy.

The Final Crossover

The basic topology of both models is a 4th order LKR (Linkwitz-Riley) crossover that allows the best integration of the purpose-designed drive units. The aim was to get a flat response with an easy load for amplifiers and a low distortion measurement. All critical inductors within the crossover design are ‘air core’ inductors – no metal cores are present in the circuit and therefore prevents hysteresis or distortion through the network. The main inductor resistance is compensated in the woofer magnet system, and so, there is no disadvantage from the slightly higher resistance of this air coil.


General Description2-way Bookshelf Speaker
Enclosure TypeBass Reflex
Transducer Complement2-Way
Bass Driver8″(220mm) Woven Polypropylene
Treble Driver1.20 (28mm) Micro-Fibre Dome
Sensitivity (2.83V@1m)90dB
Recommended Amplifier Power30-150W
Peak SPL95dB

Nominal Impedance8Ω Compatible
Minimum Impedance4.2Ω
Base Extension (-6dB)Sub43kHz43kHz
Frequency Response (+/-3dB)52Hz-23kHz
Crossover Frequency2.1kHz
Cabinet volume26L
Dimensions (HxWxD)470 x 280 x (310+36) mm