With twin 165mm bass drivers and a 46mm BMR in a 40 Litre enclosure, the S-400 is designed for more modest listening rooms and can be used with less ambitious Naim amplification. Low frequency response still reaches down to 36Hz however and the S-400 gives only very little away to the S-600 in terms of dynamics and maximum level. The S-400 gives nothing away in music making however.

The Ovator S-400's balanced mode radiator (BMR) constitutes its most visible technological advance, yet the performance of this loudspeaker is equally the result of painstaking refinement in numerous elements of design, construction, and material selection.

For example, there is so much more to the musical reproduction of bass than low frequency extension, so the Ovator S-400 LF driver is designed not simply to play bass, but to do so with faultless musical accuracy. It incorporates a multitude of electro-acoustic details aimed at minimising distortion and compression, and the result is extended bass with peerless timing, dynamics, and pitch accuracy. One vital element in the design of a high performance bass driver is its chassis. Great rigidity and an open structure are vital but potentially conflicting requirements, so the pressure die-cast bass driver chassis of the Ovator S-400 incorporates a triangulated framework, borne of finite-element analysis, that ensures both rigidity and unimpeded air passage.

The Ovator S-400 crossover network is housed within the plinth and divides the audio signal between bass drivers and BMR with fourth order acoustic slopes at 700Hz. Each component selection is the result of intense technical analysis and listening, and the component arrangement is fundamentally informed by the layout and earthing techniques developed for Naim power amplifiers. A crossover module suspension system and individual component decoupling ensures any chance of microphony is minimised. Conversion to either bi-amp or tri-amp active drive is easily achieved through removal of the crossover module*.

Just as much as it is BMR technology, it is the fine detail and the sum of the parts - the result of decades of speaker experience and development - that makes the Ovator S-400 so remarkable.

*Please note that the S-400 active crossover will not be available until late 2011.

Balanced Mode Radiator Explained

The Ovator S-400 Balanced Mode Radiator (BMR) is the result of intense effort in both development and manufacture. Not only does the design of such a driver demand great intellectual understanding, but consistent manufacture requires extraordinarily fine specification and control of the physical characteristics of its components.

The underlying concept of the BMR is to engineer a practical implementation of the theoretically wide bandwidth and linear acoustic output of an unconstrained vibrating diaphragm. In practice, this is achieved by attaching balancing masses to a constrained diaphragm in carefully calculated locations. Such 'mode balancing' modifies the diaphragm's vibrational behaviour so that it simultaneously operates in pistonic and vibrational modes to generate wide-bandwidth acoustic output with a flat frequency response, consistent dispersion and low distortion. Thanks both to the BMR's exceptional inherent performance and to the absence of any mid/high frequency crossover discontinuity, it takes just a moment's listening to appreciate the Ovator S-400's breakthrough levels of musical coherence, timing and clarity.