DESIGN RATIONALE
The seamlessness, perceived speed and live feel of the sound are thanks to a unique marriage between an E J Jordan Designs full range drive unit and a near-ideal tapered line that is designed for minimised reflection at the bends in the line.
This is very different to the majority of tapered line speakers, where the line features perpendicular angles of incidence and therefore inherent problems with reflection of sound back through the line and out through the drive unit, this can result in smearing of the sound
The actual line length of the Curvi Model 1 is 2.4 m which, together with the damping, enables a fast and extended bass response.
The unique shape of the enclosure is partly inspired by the human form. Whilst narrow cabinets are attractive they are very different acoustically to the standard test baffle environment that is actually used for the measurement of drive unit frequency response. The narrow baffle can lead to diffraction losses that reduce the perceived loudness at low frequencies and therefore cause the speaker to sound thin.
Designers of single driver speakers do not always take diffraction losses into account. The Curvi design does account for such losses with a high performance compensation network formed from the highest quality low loss components comprising of a high power Vishay thick film resistor and 1.25 mm wire inductor.
The virtues of the single driver approach are thus fully preserved at the same time as maintaining a realistic frequency response.
DRIVE UNIT
The E J Jordan drive unit used in the Curvi Model 1 is truly special and is a result of over 40 years of research by Edward (Ted) Jordan. Ted is undoubtedly the father of practical full range drive units that have none of the colourations and limited power handling and bandwidth of the very retro (in the worst sense) paper coned units that often feature "whizzer" cones.
The large excursion of the E J Jordan unit enables full-bodied bass and high sound levels; such characteristics elude other single driver speakers of domestically acceptable dimensions. An advantage of a single driver is the absence of a crossover network; even the best of which can wreck impulse response and thus rob the reproduced sound of its live tangible quality.
The initial transient of a note is arguably the most important component of instrumental timbre. Excellent imaging characteristics are a virtue of the Curvi Model 1 thanks to the single unit acting as a true coincident source.
ENCLOSURE
The enclosure design is an essential part of the Curvi 1; this element is missing from all other commercial designs that use a similar E J Jordan driver.
The Curvi enclosure is responsible for preserving the inherent fast response characteristics of the drive unit whilst providing acoustic reinforcement of the bass frequencies in a controlled and even manner.
It is formed from vertical laminations of birch plywood that are machined on a CNC router then hand assembled and painstakingly finished. This construction method ensures that a large proportion of the wood grain in each ply is perpendicular to the propagation direction of vibrations fed into the cabinet walls.
In this orientation, energy dissipation is higher as the sound has to propagate though the cellulose fibre interfaces. The multitude of adhesive interfaces of varying stiffness/damping characteristics also contributes to rapid energy dissipation.
The nature of the side wall profile of the enclosure results in unsupported spans being short and of varying length. This keeps the resonant frequencies high, which ensures significant damping, and the varying span length spreads what little resonance that remains over a wide range of frequencies.
Structural resonance of the cabinet is therefore benign and insignificant.
Designer The Curvi speakers are designed by Dr Chris Liauw, a Senior Research Fellow of the Manchester Metropolitan University (MMU), whose day job involves researching polymer-based composite materials.
Even before joining Manchester Polytechnic (now MMU) in 1986 as an undergraduate he had a strong interest in loudspeaker design and a passion for live music that is satisfied to this day, thanks to the great classical, jazz and rock musicians and venues in the vibrant city of Manchester.
The Curvi Model 1's are the latest in a line of four previous speaker designs and are the first to use a single driver.