This innovative approach gives us a considerable advantage in developing subwoofers. Until now it has been impossible to accurately reproduce the sound of some instruments, such as the timpani and contrabass, in the presence of a full orchestra. In this setting the uncontrolled acoustic delay of these sounds has seemed to be out-of-step with the rest of the orchestra. By contrast, as the design of TD725sw is based upon the Time Domain theory* of 'accurate waveform reproduction', TD725sw is able to offer totally accurate low-frequency reproduction, perfectly tracking even the most subtle changes of timing and tempo. This new standard of performance has, for the first time, satisfied those artists who previously had been openly critical of the low-frequency response of conventional subwoofers.
Of course, the development of such an radical subwoofer has not been easy, necessitating considerable trial and error and pushing to the limit of today’s audio knowledge. The ultra fast TD725sw subwoofer provides both the power and accuracy needed for true high-end applications, and is the result of both original technology and dedication to precision throughout the development phase. The accurate waveform reproduction of deep bass recreates the full acoustic of the sound field environment, and brings the listener that one step closer to the original performance.
R2R Twin Driver, providing world-class levels of high-speed reproduction
Ultra fast drive-units for accurate reproduction of the acoustic source
Drive-units require real power to displace large volumes of air in order to reproduce low frequencies. Although large drive-units are required to reproduce low frequencies with a characteristic richness and punch, both the volume of air displaced and the weight of the driver unit increase proportionally to the size of the unit. The sheer bulk involved results in inertia causing the cone to be slowed or delayed, thereby creating a delay in the bass sounds relative to the rest of the music. To solve this problem TD725sw uses two relatively compact 25cm drive-units which are mounted horizontally in a back-to back configuration. This unusual design offers power and high speed, whilst still achieving the displacement of air equivalent to using a conventionally big, heavy and slow 35cm diameter drive-unit.
A Unique stabiliser mechanism to improve linearity and instantaneous power
The drive-unit array effectively operates as two high-speed pistons which create the rapid rising and falling pressure of air required for 'accurate waveform reproduction'. However, this is only effective if the non-moving frame parts of the drive-units are rigidly fixed; ideally by being firmly and securely anchored to the ground. In TD725sw the two drive-units are mounted horizontally back-to-back and rigidly connected by an aluminum shaft. In addition the in-phase driving motor system ensures that the frames of the high-mass drive-unit experience hardly any movement, and become a virtual infinite ground anchor. This increases the radiated sound output of the overall unit so energy that would have been lost in detrimental internal vibration has instead become additional sound output.
A floating structure maximises isolation
'Accurate waveform reproduction' has been made possible through the use of a high-speed drive-unit array, yet regardless of how near we approach accurate waveform reproduction, any direct connection between the array and its enclosure will cause the powerful cone movement to be transmitted to the enclosure where they will cause unwanted resonances. These are heard as additional colourations which corrupt the sound and alert the listener that the sound is not natural but emanates from a loudspeaker. In TD725sw this problem is virtually eradicated by using isolating materials such as felt and poron to cushion the drive-unit array allowing it to float and minimising the transmission of vibrations to the enclosure.
A high-power 500W digital power amplifier
An amplifier with an output of several hundred watts is required for optimum performance of the unique drive-unit configuration. Traditional analogue amplifiers create a lot of unwanted heat and tend to be bulky in construction, using much of the internal space needed to achieve the best low-frequency acoustic performance. For these reasons ECLIPSE TD has evolved a compact digital power amp with high energy conservation efficiency, enabling a significant improvement in the internal cubic capacity of the subwoofer and thus ensuring excellent linearity, even at maximum output levels.