An alternative to this concept is to dispense with a fully conductive membrane and instead use a wafer-thin plastic film to which conductor tracks are applied. With this technique - which Raidho is also using - it is easier to realise an impedance in the normal range between 4 and 8 ohms, as longer and thinner conductor tracks are possible here, running meander-like across the diaphragm. Speakers that make use of this concept are also called "semi" ribbons or magnetostats. The foil used by Raidho is said to be record-breakingly light at only 20 milligrams and a full 11 microns thick. The version of the "ribbon" used in the TD1.2 has also been given a particularly powerful motor that increases sensitivity by three decibels compared to the previous model. The acoustically optimised chamber behind the foil should lead to a further reduction of distortion by 35 decibels compared to the already extremely low values of the previously employed version.

Almost more complex than the construction of the ribbon is the manufacturing of the midwoofer with its diameter of 11.5 centimetres. Right from the beginning, Raidho has relied on composite materials for the diaphragm technology. The advantages lie the individual balance between high torsional stiffness on the one hand and high inward damping on the other. With the technology used in the TD1.2, the effort was taken to the absolute extreme. An aluminum cone with a ceramic coating forms the basis of the diaphragm. Added to this are layers of tantalum, which is extremely hard and stiff, and - yes, you read that correctly - diamond. Raidho specifies 10 micrometres or 1.5 carats of diamond on each membrane. The tantalum/diamond layers are said to reduce resonance by 36 decibels compared to ceramic and to be 50 times stiffer than a pure ceramic diaphragm. At the same time, this is said to have raised the resonance frequency to 20 kilohertz. The result of this enormous outlay is said to be a perfect transient response without measurable distortion. The motor is based on neodymium ring magnets with optimised magnetic field characteristics, which, in interaction with the underhung titanium voice coil wound in flat wire, ensure that an extremely strong magnetic field is created inside the driver. This should lead to a drastic increase in dynamic performance. However, the effort expended doesn't stop with the drivers. The crossover of the TD1.2 was completely redesigned, with the focus on a correct phase response at all frequencies and an optimal impulse behaviour. Only a few, but very high-quality components from Mundorf are used here. The wiring is point-to-point, waiving therefore the customary circuit board.

Each driver is mounted in its own solid aluminum frame, which is fixed to the baffle with four screws each. The frames are rounded to avoid diffraction effects at the front of the speaker. The lower baffle section is slightly tilted to optimise phase response. The curved cabinet, optimised for low resonance, tapers slightly towards the rear and is reinforced by a thick aluminium backbone accommodating for the bass reflex ports. The optimised crossover and the new driver design afore described should lead to a considerable improvement in efficiency - not exactly one of the strengths of Raidho speakers up to this day. In operation, I got by with the modest output of my Omtec CA 25 without any problems.