The TCD 210 S is the second largest speaker in the TCD series, and is of very similar construction to the top model, the TCD 110 S; their internal mid-range / treble components are actually identical. The TCD 210 S is a no-compromise floor-standing transmission-line speaker fitted with a very long transmission line. Two massive 22 cm bass units with low natural resonance are accurately tuned to this line, and their extremely hard, embossed cones generate unbelievably low, accurate bass at very high sound pressure. The same drive units are also employed in our High-End SOLITAIRE® loudspeaker speaker line! We have developed a unique technology for the mid / treble range by using a D’Appolito arrangement together with our Waveguide dome tweeter. This concept results in an incredibly precise and dynamic reproduction, harmonizing perfectly with the bass drivers.
Two mid-range drive units and the Waveguide dome form an acoustic unit which we have designated CD = Constant Directivity. This concept is unique, and was perfected by our engineers in a complex series of simulations and measurements. The radiation pattern of loudspeakers varies with rising frequency, leading to an increased sound focusing effect with conventional drive units, with the result that the mid-range unit tends to be more directional with increasing frequency, and the tweeter unit more omni-directional in the crossover area between mid-range and treble. This results in inconsistent imaging, and a loss of positional accuracy. From experience with our SOLITAIRE® loudspeakers we are aware of the enormous sonic advantages offered by constant radiation characteristics in the mid / high-frequency area in terms of accurate positioning and good imaging. We have succeeded in this with our SOLITAIRE® speakers by investing enormous effort in the mid-range arrays and extended electrostatic units, which are designed to generate cylindrical waveforms.
Naturally such sophistication does not come cheap, and can only be exploited in expensive loudspeakers. However, our development team has succeeded in achieving similarly good results with cone-based loudspeakers by taking an ingenious approach: the use of two mid-range drivers in the so-called D’Appolito arrangement results in energy compression in the listening area, and a reduction in sound radiation upwards and downwards, thereby reducing reflections from ceiling and floor. The 25 mm woven dome is fitted with a carefully calculated Waveguide (sound guide) whose depth and shape mold the radiation pattern in the transitional area to match that of the mid-range drivers.
The net result is that the radiation characteristics of the tweeter and the mid-range units are very similar and homogeneous over the frequency range. This ingenious concept produces incredibly precise, dynamic reproduction with tremendously fine definition and excellent detail reproduction. The arrangement avoids the usual “step” in the sound image, producing a listening zone in which the sound and imaging characteristics are totally homogeneous. The system also offers another major advantage: it reduces overall distortion to an extreme extent, because even at very high levels the excursion of the paired mid-range units is not great, and at the same time the dome’s Waveguide causes a considerable gain in sound pressure, which in turn reduces distortion to a vanishingly small level.