Our TTC-PRO loudspeaker cable - an optimisation of true sound transmission - has been developed with the professional listener in mind.
It does not cover up weaknesses in your hi-fi system, nor does it follow your personal taste and preferences. Yet it perfectly and accurately reflects the reality of a specific recording. It’s up to you – your judgement is crucial!
There is a variety of implementations and opinions concerning the optimal configuration for speaker cables. In order not to lose the ground under our feet, we should take a look at proven solutions used in other technical domains. In professional transmission technology, coaxial cables are preferred, since they minimize losses in high frequencies. With these cables, energy is transferred by means of an electromagnetic field, which is completely trapped and guided between the inner conductor and the surrounding outer conductor (shield). Thus stray fields and inductive components are minimized. The corresponding transmission theory is very clear and straightforward, and also in practice the conditions are almost ideal: coaxial cables are very broadband and ensure time-correct transmission of signals.
Now, what about speaker cables? Conventionally either twin cords of stranded wires with large diameters or cables braided from multiple strands are used as speaker cables. These cables diffuse a part of the electromagnetic field into their surroundings. This increases the inductive component of the cable impedance, and thus causes losses at high frequencies and also results in frequency-dependent transit times (dispersion), which deform the time response of the signal. The higher-frequency signal components are delayed and might be concealed by the lower-frequency components of the signal spectrum.
Investigations into time behaviour of conventional cables reveal deformations at fast signal transitions (transients). The effects are in the percentage range depending on the cable, but they may cause even greater impact on sound quality compared to equally large harmonic and intermodulation distortions. The signal deviations not only affect the transparency of complex signals, but may also have physiological effects. Our hearing is continuously busy with pattern recognition and is especially interested in transients (clicks, crackling noises, etc.). These are compared with stored signal patterns and analysed for possible danger potential. This process is genetically implemented since primeval times and may be essential for survival. Therefore, it is constantly and subconsciously active. Adulterated acoustic information irritates and burdens the recognition process, and can cause long-term fatigue and annoyance. Thus, time-correct reproduction of complex signals, particularly fast temporal changes, is important for fatigue-free and relaxed listening.
The skin effect is another physical characteristic that occurs in all current-carrying conductors. It describes the frequency-dependent penetration depth of the electric field into the conductor, and therefore the distribution of the current density inside the conductor. In the case of DC and low AC frequencies, the current is homogeneously distributed across the conductor. With higher frequencies, however, it increasingly moves to the peripheral area of the conductor. This effect is already noticeable at higher audible frequencies. For copper conductors, the penetration depth at 20 kHz is only about 0.5 mm. This means that 0.5 mm below the surface the current density is decreased to nearly one-third and it continues to decrease further exponentially towards the center. In order to achieve frequency-independent conditions in the entire audio range, the conductor diameter must be less than 1 mm. So it's better to use thin instead of thick conductors. Furthermore, strands of thin wires that are not insulated from one another do not improve the situation. Due to the skin effect they behave like a thick solid conductor since it‘s mainly the outer strands that carry higher frequencies. A detailed description of cable issues can be found at .
Which conclusions can we derive from the current knowledge? Without a doubt, coaxial cables improve the fidelity of audio signals because their inductive impedance component is lower than that of other types of cables. Furthermore, the skin effect directs us to use cables with thin solid inner conductors. Parallel connection of several coaxial cables reduces the losses even more, and provides sufficient reserves for high power applications.
Comparisons with different types of cables have confirmed that such configured coaxial cables actually yield the best sound results. The overall result is a more transparent and homogeneous sound image with improved localisation and an impressive spatial depth. But there is another effect to consider when coaxial cables are to be used as speaker cables. Ideally, coaxial cables are terminated at both ends with the characteristic impedance of the cable, which is typically 50 - 75 Ω. This helps prevent signal reflections, which can result in distortion. When these cables are used as a speaker cable, however, other conditions prevail. Amplifiers with high damping factor provide extremely low output impedances, and speaker impedances remain far below the characteristic cable impedance. These termination conditions lead to a mismatch between the coaxial cable and its associated signal reflections and deformations. Thus the cable may introduce its own sound signature depending on the amplifier and speaker.
What can be done to prevent, or at least reduce this effect? A very effective option is the parallel connection of an additional line with slightly different characteristics, which takes over part of the signal transmission. This hinders the formation of reflections, and the cable becomes largely neutral. This additional line must be carefully tuned to achieve the optimum effect. For TTC-PRO, this parallel cable is specially made by a renowned cable manufacturer. It is dimensioned so that the total resistance is extremely low. As a result, the coupling between the amplifier and the speaker is as direct as if the cable is not present at all. The amplifier seems to be integrated into the speaker. The use of basalt fabric as a cable sheath yields another improvement. The magnetically active components cause a further attenuation of interfering cable reflections.
The TTC-PRO was developed on the basis of the aforementioned findings. The use of coaxial conductors results in nearly perfect signal transmission. Due to the optimised design, the skin effect is negligible throughout the total audio range. Through the parallel-connection of several coaxial conductors, the cable is very low-loss and the increased conductor cross-section provides sufficient reserves for high power signals. Due to its special signal transmission and magnetically active sheath, the cable is further perfected.
Last but not least: The TTC-PRO uses rubber sleeves at the cable ends to prevent rattling and vibration noises on the back of the speaker, which can otherwise occur with wood or metal parts, and the connecting strands were made very short so as not to impair cable performance.
The positive impacts of these decisions are obvious and have been confirmed by extensive listening tests with many speaker-amplifier combinations. The TTC-PRO claimed its lead in all cases. A good indicator of the quality of this cable is reduced or absent annoyance during long-term listening, even at a higher volume. It may even trigger a desire for louder listening in order to discover more details, which was not the case with other cables. The True Transmission Cable TTC-PRO was primarily developed for professional use. But also in the private domain, this cable can make a decisive contribution to the perfect sound experience.
With the TTC-PRO you will probably have for the first time the impression that everything is just right. Some disturbing effects that were previously accepted as characteristics of loudspeakers and amplifiers may now disappear. Spatial impressions, presence and clear contouring of sound sources become impressive. The impact of a piano is reproduced so authentically that the instrument seems to be physically positioned in the listening room. With closed eyes, one can experience a private concert. It’s as if the instruments are played live in the room, the musicians almost touchable. Due to the precise time response, the sound is never harsh, but remains always delicate and differentiated. String instruments don‘t move towards the listener in their higher registers, but remain in the same spatial position in the orchestra. Text intelligibility of choirs is improved and the individual voices can be clearly distinguished from each other. Also artificial intermodulation effects that might be caused by mutual interactions of voices and instrumental sounds are missing. If the listening experience had to be summarised with a single word, “true” would be the correct adjective.
 The Essex Echo 1995. Hawksford: Electrical Signal Propagation & Cable Theory