Pro Audio Cables | Frequently Asked Question

FAQ - Frequently Asked Questions

Why Do Cables Twist?

During the production process, almost every multiwire cable in the audio and video sector is submitted to stranding or laying direction to give the cable its compactness and bending properties. As a result, multiwire cables are most often stranded in multiple layers.

Highly flexible cables are subject to an increased torsion strain, often taking the stranded compound to its breaking limits. For technical reasons, the stranding elements in the stranding layers are of different lengths and thus, of course, also subject to various strains, which is why in some multiwire cables, the inner elements (such as the contact points at the connectors) will often tear first. However, a wire bundling would be ideal, which is not possible in some instances (e.g., with 4- or 8-wire speaker cables) because the wires would become too thick and cumbersome then.

If the cable is forced into an unnatural position by an extreme or reverse bend and at the same time exposed to tensile forces, the individual wires may" jump "out of their guides and cannot slide back anymore. The result is a formation of knots or cable twisting. Glueing cables together with other cables is not recommended either because a" jam "can occur just as quickly in this constellation since the wires within the stranded bundle cannot relax.

Some cable makers think they can avoid the problem by simply injecting a thicker outer jacket in the extrusion process as a means of protection for the inner elements – provided the overall diameter allows it. But this will only shift the problem into the cable interior because instead of the overall construction, the individual wires will now twist and tear.

SOMMER CABLE has employed a new, zero torsion stranding method (X-Torsion) for quite some time which handles this problem very well. Yet, the case of improper handling of the formation of knots cannot be avoided completely. Would you please relax cables before reeling or lay them out full length before reeling them onto a cable drum?

Does the optimum guitar Cable length only depend on the cable values?

It is not easy to answer this question because a low capacity is essential for the sound of a guitar cable, but the entire cable construction must be considered.

A guitar cable can have an extremely low capacitive value and still sound "faint "or flat. Often, the individual litz is stranded parallel instead of concentric (as is the case, e.g. at SOMMER CABLE). Parallel stranded litz not only have too small a conductive surface but also breaks real fast. Too small a conductive surface is even noticeable on a bass cable: It transmits the typical deep sounds but will be missing the all-important "attack "and the dynamics.

The insulation material on guitar cables with an almost unbelievably low capacitive value is often very highly foamed. But highly foamed insulation material is susceptible to pressure and looses stability after having been wound only a few times (i.e. after each gig). The capacitive values thus increase. To avoid this effect, SOMMER CABLE uses an exceptionally robust and lacquered insulation material to finish off porous surfaces. Thus, cable manufacturers have to find a compromise between good electrical values and continuous stability for insulation and jacket.

If merely the capacity is considered, the cable would be 30 cm long, which would not be very practical. The solution: Testing the sound or sound characteristics of different cables, selecting the shortest available cable length for the selected version (mostly 3.0 m or 4.5 m). To be on the safe side.

What's the difference between diameter and cross-section?

The diameter in mm is a linear measure, the cross-section in mm² is an area measure. For solid conductors and single wires, the diameter is specified in mm. For inner conductors, which consist of multiple single wires/braided wires, we quote the cross-section.

The cross-section (A) can be calculated from the diameter (d) using the following formula: A = (d² x Pi)/4 ≈ 0.785 x d²

What is the maximum transmission length for HD-SDI cables?

That's hard to say because it very much depends on the peripherals used and the quality of the interface installed. The question is comparable to the one you would ask the filling station attendant: If I fill 10 litres of gasoline into my car, how far can I drive? The answer to the question would depend on the type of vehicle, and the same is true for HD-SDI cables. Here too, the hardware data must be considered and used to calculate the transmission length. An SDI-cable should be capable of transmitting 270 Mbit/sec., the HDTV cable is designed to transmit within a range of 1.5 Gbit, thus providing the resolution required for the PAL 625-line format. The scope of the HD-SDI depends on the bitrate used (compressed or not compressed). At 1.485 Gb/s (not compressed), the damping value is drawn on at half the bit rate (720 MHz), and the cable length possible at a damping value of 20 dB or 30 dB is considered a relevant parameter.

How important is the gold-plated contact on a plug connector?

But let it first be mentioned: Pins made of genuine gold would be too expensive and not make any real technical sense. Gold is a heavy metal and would, without an alloy treatment, break after only a few plug cycles. To affect hardness and surface properties, mostly nickel-plated pins or alloys are used. Most plug connectors are only lightly goldplated, and reasonably priced ones are sometimes only painted, which means that a genuine cheap plug connector cannot be gold-plated. The good conductive values of gold can only be utilized if both socket and plug are gold-plated. The harder alloy scrapes off the soft gold and oxides build up if this is not the case. Contrary to public opinion, the layperson cannot recognize the quality of the gold by the colour because very often, depending on the application and plug cycles, more complex alloys are used on the plug connectors.

How important is the quality of the solder?

The quality of the solder and especially the quality of the soldered spots should not be underestimated for the transmission of audio signals. Bad solder or a soiled solder bath can cause the transmission resistances to increase. This is not only physically detectable but in rare cases, it can also be heard. So, use high-quality solder to work with (partially with silver), make sure to provide a clean working environment and do not touch the wire insulation with the solder tip.

What is the difference between an unbalanced and a balanced cable?

The unbalanced cable is mainly used to connect guitars and amplifiers, HiFi components, or a simple control cable. It consists of a signal wire and shielding.

The balanced cable has two signal wires with a phase twisted by 180° (±). The opposite phase releases interference signals, which is why this type of cable is preferred for long transmission distances or sensitive, interference-prone components such as microphones and mixing boards, etc.

What is the difference between a CAT.5 CAT.6 and a CAT.7 cable?

The simple CAT.5 standard was designed for 100 Mbps LANs and was established around 1990. However, as is common in the fast-changing world of computer technology, this standard soon reached its limits. So it was replaced by the CAT.5e standard, which supports the operation of full-duplex fast Ethernet and Gigabit Ethernet. CAT.5 is a 100-MHz standard, just like big brother CAT.5e.

In June of 2002, the CAT.6 standard was ratified by TIA/EIA, with a significantly higher performance than the CAT.5e standard and a transmission capacity of 250 MHz. Of course, all CAT.6 components are downward compatible with CAT.5e components. CAT.7 cable is designed for data transmission up to 600 MHz and CAT.7a up to 1000 MHz. It is favoured for use in buildings because the wire pairs are individually shielded, with very low cross-talk.