Like the S Series, which launched in 2015 to widespread acclaim, the new range combines advanced Kevlar-coned bass and midrange drivers with a specially designed ribbon tweeter. The Z Series takes this fundamental design to a whole new level, however, re-engineering the drive units, crossovers and cabinets to provide the perfect bridge between the entry-level S Series and Quad’s classic electrostatic ESL speakers.
The range comprises two standmount models (Z-1 and Z-2) and two floorstanders (Z-3 and Z-4). The Z-1 stands 383mm high and incorporates a 150mm bass/mid cone, while the larger S-2 uses a 175mm bass/mid cone. The two floorstanders sport three-way configurations, coupling a 150mm midrange driver with two 175mm bass drivers in the Z-3, and three 165mm bass drivers in the Z-4.
Ribbon tweeter ensures treble soars
All Z Series models sport a bespoke ribbon treble unit, delivering effortlessly extended high frequencies that are audibly superior to those supplied by typical dome tweeters. The use of a ribbon-based driver is not new to Quad; in fact, the company’s first loudspeaker was known as the Corner Ribbon, launched in 1949. Back then, ribbon drivers were delicate affairs, easily prone to burning out if overpowered.
Like the ribbon unit developed for the S Series, the composite sandwich construction of the Z Series ribbon ensures it is robust enough to handle high-powered amplifiers, but at 90x12mm it is significantly larger than the S Series ribbon. In fact, it is the largest ribbon treble unit that Peter Comeau, Director of Acoustic Design for Quad’s parent company IAG, has ever worked with, delivering greater sensitivity and bandwidth for even better dynamics and smoother integration with the midrange frequencies.
This large ribbon driver is fully immersed in a powerful magnetic field so that it accomplishes its dual role of being both the voice coil and the sound radiator. This is a key difference between ribbon treble units and conventional dome tweeters, in which the voice coil ‘motor’ is attached separately to the diaphragm.
As well as delivering excellent transient response and superb musical detail, the sound from the Z Series ribbon treble unit is smooth right up to the highest musical overtones beyond the limits of human hearing. Controlled directivity maintains this sound quality over a wide horizontal arc to cover all listeners whilst vertical dispersion is tailored to avoid floor and ceiling reflections, resulting in the purest high frequency performance at the listening seat.
Kevlar cones deliver bulletproof sound
Designed especially for the Z Series, the speakers’ bass and midrange drive units use cones fashioned from woven Kevlar – an exceptionally strong yet light aramid fibre that is as ideally suited to speaker diaphragms as it is body armour. A key feature of these drive units is their unique double-roll cone surround, which controls breakup modes to enhance accuracy and transparency, coupled to a cast aluminum basket providing a stable chassis for the driver motor systems, thus enhancing transient performance.
All the Z Series models feature acoustic filter bass reflex loading. This incorporates a dual-chamber filter system inside the cabinet, with the reflex port exiting via a specially shaped expansion chamber in the plinth that is filled with resistive foam. The result is the sensitivity and extension expected from a bass reflex system but with the clarity and transient attack of a closed box design, entirely avoiding the turbulence and ‘chuffing’ often associated with conventionally ported speakers.
The treble, midrange and bass units are aligned via a phase-compensated Acoustic Butterworth crossover devised using advanced computer-aided design coupled with hundreds of hours of listening tests with all manner of music. Effortless sonic expression results, capturing all the nuances and passion of the original musical performance with a beguiling fluidity and hear-through transparency reminiscent of Quad’s worldfamous ESL electrostatic speakers, available in a range of cabinet sizes to suit any room.
Cunningly constructed cabinets with comely curves
Every Z Series model sports a cabinet constructed from multiple layers of wood fibre composites of varying density, extensively strengthened using multiple circumferential braces, all of which reduces panel resonance to below the level of audibility. Internal long hair fibre damping helps to absorb unwanted reflections in conjunction with the scattering effect of the curved cabinet sides, thus minimising coloration.
Each speaker is endowed with a luxurious piano lacquered finish, splendidly complementing the elegantly boat-tailed sides and smoothly curved top. Multiple layers of piano lacquer are applied over black, white or rosewood veneers, each layer being hand-polished to a high gloss before the next layer is applied. This gives magnificent depth and colour to the speakers’ exterior – an impeccably crafted appearance to match their compelling sonic performance.
Commenting on the design of the Quad Z Series, Peter Comeau said: “The Z Series is the pinnacle of Quad’s enclosure speakers and features the largest ribbon treble unit that I’ve ever used, giving the Z Series a clarity and definition throughout the upper midrange and treble that is utterly beguiling. This combines with the acoustic filter bass reflex system and low-coloration enclosure to deliver the perfect embodiment of the natural sonic realism that is the hallmark of Quad, in line with the company’s traditional dictum: ‘The Closest Approach To The Original Sound’.”
Recommended retail prices
Z-1: £1199.95 per pair
Z-2: £1499.95 per pair
Z-3: £2499.95 per pair
Z-4: £3199.95 per pair
The Quad Z Series is available in piano lacquered black, white or rosewood.
