QED XT25 Speaker Cable - Per Metre

QED's latest entry-level XT25 speaker cable is intended as a 'first upgrade' cable for systems of all types: stereo, home cinema or custom install. The cross-sectional area (2.5mm²) makes it ideal for longer runs.

Similiar to the other QED speaker cables, the XT25 follows the framework from the 'Sound of Science Report' and these cables are so good, QED is able to offer an unlimited lifetime warranty. Please note, this cable is supplied UNTERMINATED (without plugs) however you can also order QED's 4mm Airloc plug or spades separately and we also offer a termination service - view your options here.

X Tube Technology

X-Tube technology introduced in the world-renowned Silver Anniversary XT, is the most highly awarded mid-range cable in the world, winning the What Hi-Fi Product of the Year three years in a row. The X Tube technology has been employed with these multi-award-winning XT40 speaker cable.

In cable design, the issue is that the electron flow gravitates toward the periphery of the conductor, as a function of increases in frequency. Therefore, when the frequency is relatively high, only a very thin layer on the outside of the conductor is used. Known as the “skin depth” effect, is different for different materials at a fixed frequency and with copper, it means that if a conductor has a cross-section larger than 0.66mm², not all of it is able to receive an analogue signal.

X-Tube Technology was employed for SAXT and the “skin effect” has been effectively removed, by organising conductive material around an insulating central hollow rod. However, for AC. signals by altering the magnetic fields that are the result of current the current flow, they cause eddy currents in nearby conductors which makes the current flow only in areas furthest away from the conductors carrying current in the same direction and vice versa. The “proximity effect” has a negative effect on the distribution of the current in the cable even if X-Tube Technology has been used.

Aircore Technology

These are tackled by combining existing Aircore and X-Tube Technologies into a new X-Tube variation. By placing the conductors in a tube configuration, hollow centre, the density of the current with high frequencies are maintained because the electric field which is a significant contributing factor the skin effect are forced toward the conductor's centre, which is now hollow.

These cables are formed with a braided structure, the conductors are in a ring, formed into separate bundles with only a loose electrical association between them, they are then twisted into a 90mm layer. By designing the cables as they do, QED ensures that no single conductor bundle remains on the inside or the outside of the cable long enough to become an audible problem. The resulting design has a consistent signal distribution which gives an accurate musical reproduction.

Low DC Resistance

QED understands the low DC resistance, of a cable, is important for high-quality transfer of audio signal. Low DC resistance is important because the speaker is a frequency dependent load leading to the amplifier of which the cable forms a variable proportion. If resistance is large enough, frequency responsiveness of the speaker will change, which is unable to be corrected for by the negative feedback loop in the amplifier.

To produce a cable that is a significant improvement over other competitively priced cables, in their own range or a competitors’, without increasing the size or flexibility of the cable, the cross-sectional area (CSA) of XT25 has been increased to 2.5mm2 with 99.999% oxygen-free copper. The design of the XT25 creates a new cable with low DC resistance and a substantially more accurate musical representation.

Low Loss Dielectric

Since electrical signals travel close to the speed of light in the form of electromagnetic (EM) waveforms, and they exist within the dielectric which surrounds the conductors as well as within the conductors themselves.

The electrons travelling within the conductor lead to electro-magnet waveform as their “drift velocity” is a few centimetres per second. It is important to ensure that the dielectric material used to protect and insulate central conductors in the cable is designed to aid the creation of electro-magnet waveforms without any noticeable loss.

Dielectric losses

Dielectric losses are directly proportional to the “permittivity” of the material being employed, and because the size of the material relative to that in a vacuum it should be as close to unity as possible. Similar to it predecessors, XT25 has a purpose-designed LDPE (Low-Density Polyethene) dielectric which at 1.69 has one of the lowest relative 'permeability' available in cables.

QED's R&D has revealed that low capacity cables are preferred in listening tests over high capacitance cables because low-loss dielectrics have been used. Using LDPE and carefully controlling conductor spacing results in a cable with very low capacitance as a function of length and a dissipation factor (loss tangent) of 0.0001 at 10,000Hz