The leading edge of a musical note. Every type of musical instrument has a distinctive shape to the notes played on it. The attack is the time taken for a note to rise to its full loudness. Poor quality cables can have a seriously detrimental effect on what is a critical part of music. The initial rise on a note can be lost beneath a high noise floor or altered by interference or mechanically induced noise

An audio signal can be carried from one component to another in two ways, either single ended or balanced.  A single ended output will usually use an RCA or DIN connection (very occasionally and somewhat confusingly, single ended outputs may well use an XLR connector).  The majority of hi-fi components are fitted with RCA sockets.  Most professional audio and some domestic components offer the option of a 3 pin XLR connector.

A balanced connection can offer some serious advantages over an RCA connection.  One pin of the XLR carries the signal, another the earth/return and the final pin carries a mirror image of the signal.  When the signal arrives at its destination, it passes through a transformer and any signal (including noise or interference picked up along the length of the cable) common to both the original and the mirror image of the signal is cancelled out.  This makes the XLR balanced connection extremely useful for long runs of cable and is the reason for its popularity in professional recording studios.

If your equipment offers balanced and single ended connections we would advise experimenting.  In some cases the XLR connection can produce a significantly better sound quality and in others, the RCA connection can produce the more satisfactory sound.

Connecting RCA outputs to XLR inputs

It is possible to connect either an RCA output or input to an XLR input or output.  This is done by connecting the signal pin on the XLR to the tip of the RCA.  The earth/return pin is connected to the RCA surround and the out of phase (mirror image) pin is shorted to the earth pin.  This configuration works well and allows the connection of a component fitted only with balanced outputs to an amplifier or pre-amp that only has RCA inputs.  The only potential problem with this is that XLR outputs often have a higher output level than RCA outputs, so you may need to watch the volume control.

In hi-fi terms, bandwidth describes the effective frequency range of a loudspeaker or system. Bandwidth is a useful term to describe a cable’s ability to accurately carry a signal over a given frequency range.

If used to explain the performance parameters of a cable, bandwidth would be used to describe the ability of the cable to transmit very high and low frequency information. As cable design gets more exotic so its ability to transmit this information accurately improves.

The best example of a coaxial cable is one that connects an aerial to a television. An insulator and shield surround the central conductor. The signal travels along the central conductor and the shield screens the signal from interference and provides a return path to complete the circuit. Coaxial cables are used extensively to produce analogue and digital interconnects. We use high quality coaxial cables to produce digital interconnects, but feel that analogue signals are better carried via a pseudo-balanced configuration cable.

A term used to describe the ability of a hi-fi or home cinema system to present music as a complete and understandable whole.  It can be easy to slip into thinking about the bass, middle and treble frequencies whilst losing sight of the fact that the music you are listening to is not actually being presented in a coherent manner. The way in which interconnects or speaker cables affect the coherence of a system can be dramatic. Badly designed and poorly built cables can almost completely destroy a system’s ability to produce a coherent sound. Crucial to a system’s coherence will be a cable’s ability to move dynamic and tonal information accurately across a wide bandwidth

In the case of cables, conductors are the wires used to carry the signal. These can be either multi-stranded or solid-core.

A multi-stranded conductor will be made up from a number of strands; there can be a considerable variance in the number and diameter of strands used and the way in which they are configured.

A solid core cable has a single strand conductor and as with multi-stranded conductors there can be a great deal of variation in the diameter of the single strand.

The unit of measurement used to describe the loudness of a sound, the higher the louder. The rock band Motorhead are reputed to have played concerts at volumes in excess of 130 decibels!

The dielectric (or insulator) is the material used to insulate conductors, either from each other or from a surrounding shield. The most commonly used dielectrics are all plastics and each type has a different set of electrical properties. Until recently, PTFE was considered one of the best dielectric material to use, but polyethylene can also be made to measure and perform extremely well. Bottom of the list in performance terms is PVC.

The dynamic range is the difference between the quietest and loudest sound. The human ear has a dynamic range of around 140 decibels (dB). Almost every hi-fi and home cinema component will list its dynamic range. No cable can increase the dynamic range of a system, but a poor quality cable can significantly reduce it.  This can be caused by poor quality shielding which significantly raises the noise floor of the system, meaning that very quiet sounds are masked by unwanted noise.

A term most often used to describe the shape of a note created by an electronic instrument that has been altered electronically.   It also has some relevance when used to describe any musical note created by an acoustic instrument.  The envelope of a note played on a piano will be completely different to the same note played on a banjo. A musical note can be split into three sections.

Attack – how long a note takes to rise from start to maximum volume.

Sustain – how long a note stays at maximum volume.

Decay – how long a note takes to die away.

Most commonly used by hi-fi manufacturers to describe the frequency range of components, particularly speakers (e.g. 50 Hz to 20 KHz). We might use it to describe a cable’s ability to accurately carry signals over a particular frequency range (see bandwidth).  In listening tests, high performance cables appear better able to carry musical information to a higher and lower frequency than poor quality cables.

A really big deal. Interference is anything that interferes with the signal travelling along the cable. This can be electrical or mechanical and is something cable designers spend a great deal of effort in attempting to protect the signal from. Interference will increase the noise floor of a system, corrupt the picture from a DVD player and will in severe cases seriously affect the performance of a hi-fi or home cinema setup.

The way in which a cable is designed, built and terminated will affect its susceptibility to either transmitted or airborne vibration. We found that cables built to a tight mechanical tolerance sounded better than those with a lower build tolerance. So we choose to build cables this way simply because they sound better. As well as insisting on a high build tolerance we use particular materials, which through experimentation we have established are effective at dealing with this problem.

Human hearing is incredibly sensitive and able to detect tiny differences in loudness. This ability is critical to the way we respond to music. A really good illustration of the way these tiny dynamic shifts are vital to a piece of music would be a piece of music played on an acoustic guitar. Music is often built around repeating rhythmic and melodic patterns, so a sequence of notes will have a regularly occurring start point. The guitar player will emphasize the start of the sequence by hitting the first note very slightly harder than the following notes. Likewise other notes in the sequence will be played slightly harder or softer to emphasize the rhythmic or melodic structure

In almost any system there will be present, when the system is switched on, a degree of noise (sometimes an audible hiss). This can be an electrical noise generated by the components within the system, or interference picked up along the length of the connecting cables.

By way of illustration, let’s assume that the noise generated by the system and/or cables is measured at 35 decibels, so any recorded sound on the music you are playing that is below that level will be masked by the noise.

A properly designed cable, with high levels of wide frequency interference rejection fitted in place of a cable without these characteristics, can significantly lower the noise floor of a system.

The outer jacket of a speaker cable or interconnect can influence sound or picture quality to a surprising degree. The most obvious purpose of an outer jacket is to protect the conductors and the shields. However, the ability of the material chosen to control and reduce external and internal vibrations (see mechanical noise) can influence the performance characteristic of the cable. We use several materials including Silicone, PVC, PTFE, XLPE and Taylon®.

Oxygen-free copper is the most commonly used conductor material for hi-fi and home cinema interconnects as well as speaker cables. Often referred to as four nines copper (99.99% pure), oxygen free copper contains around 50 parts per million oxygen, compared with around 750 parts per million found in the copper used for household appliances.

In terms of subjective sound quality, cables that use oxygen-free copper (dependant to some extent on the insulation material it is used with) produce a more detailed sound and cause less colouration of tone, resulting in a more natural sound.

This is a term used to describe a cable that has two or more sets of identical conductors. This type of cable configuration is sometimes described as balanced or semi-balanced. However this does not mean that a pseudo-balanced cable carries a balanced signal.

The term is used to describe a cable where both the signal and the return are carried by identical sets of conductors. This type of cable geometry is used throughout our range of analogue RCA interconnects; pseudo-balanced cables can help to lower the perceived noise floor and transmit dynamic and tonal information more accurately than co-axial designs.

We believe that effective shielding of both audio and video signals is one of the most critical areas of cable design.

The average house is full of potential sources of mains and airborne electronic interference, both of which can have a seriously detrimental effect on sound and picture quality. A shield does exactly what it says and protects an audio or video signal from interference.

Foil shield

At one time a foil shield was the simplest and cheapest method of providing reasonably effective shielding. A ribbon of conductive foil is wrapped around the conductor(s).

Things have now changed.   Firstly, when used in combination with any of the other shields described, a foil shield can make a significant contribution to sound quality.  Secondly, although foil shields are usually produced using very light gauge foil. We have experimented with foil shields produced from heavier gauge foil.  Difficult to apply, heavy gauge foil shields have produced remarkable results, particularly when used in combination with other shield types. Our high-end interconnects utilise a heavy gauge shield in combination with a flat braid shield. Combining foil and braided shield has proved so effective that all of Chord Company analogue interconnects feature foil shields combined with either braided or lapped shields.

Lapped shield

A lapped shield is made up of multiple strands of copper or other conductive materials wound around a central conductor in an overlapping spiral. Lapped shields are extremely flexible and when used in cables with multiple sets of separately insulated conductors, make for an extremely versatile cable that can be terminated with a wide variety of plugs.

Braided shield

A braided shield uses multiple strands of copper, interwoven around the conductor insulation. The density of the weave will have an effect on the efficiency of the shield. The density is usually given as a percentage of coverage. This can vary enormously but will typically be between 83 and 91 percent.

Flat braided shield

A variation on the more commonly found braided shield.  Flat braid shields are technically complex to apply using a flat ribbon wire in place of the more commonly used round wire.  Flat braid shield however can produce a very high coverage (up to 100 percent) and are extremely effective to very high frequencies. Chord use flat braid shielding extensively.

Combination shield

All shield types can be used in combination with each other to produce still higher levels of shield effectiveness.

Other shield configurations

There are many ways of configuring a shield or shielding system. The simplest method is to connect the shield to the plugs at each end of the cable. The shield protects the signal conductor and acts as the signal return.  However, like many manufacturers, we adopt a pseudo-balanced configuration. Since the signal return is now carried by an identical conductor to the signal carrier, the shield need no longer form part of the circuit. This means that the shield can be connected at one end only or not connected at all and left fully floating.

A lot of the cables in the Chord Company range employ silver-plated conductors. Silver has a marginally lower resistance than copper but our primary reason for using silver is its ability to accurately carry both small and high level signals across a wide frequency range. The insulating material can influence the tonal characteristics of silver. Choosing the wrong insulation materials can introduce unwanted colouration to parts of the frequency range.

Silver plating

So far we have chosen to use silver-plating rather than solid silver wire. We have experimented with this and feel that the extra price of silver wire does not justify itself in terms of performance.

Stereo image is used to describe the sound from a system as it appears between the speakers of a hi-fi system and relates to both width and depth.  If an image is good it is easy to locate individual performers and instruments and also to gain an impression of instruments being either behind or in front of each other.

Image can also relate to the ability to place a sound at a particular height.  This is an area where cables can play a massive part in producing a good and believable image and for many people, good imaging adds hugely to the pleasure of listening to reproduced music

In “This Is Your Brain On Music” (by Daniel Levitin) can be found the Acoustical Society of Americas definition of timbre:

“Timbre is everything about a sound that is not loudness or pitch”.

The only way this helps is by illustrating just how complex timbre is. Timbre is the information that lets us define what a musical note is played upon. The timbre of a note played on a guitar is completely different to the same note played on a piano. Two otherwise identical guitars can have very different sounds because the body of one is rosewood (brighter tone, better defined bass) and the other mahogany (softer, less attack to notes). This barely scratches the surface of what is a vast and complex subject, but it is one of the areas where properly designed cables can have a profound effect.

One of the biggest challenges for anyone involved in hi-fi design are bowed instruments. The tonal complexity of a string quartet is extraordinary and it was the desire to transfer as much of that complexity as we could that led to the use of the advanced shielding systems we use in many of our cables. Timbre also plays a vital role in the way music communicates emotions and our emotional response to music is critical to our love of music.

This is a hugely important area. It is vital that a hi-fi or home cinema system performs in a coherent manner (or with good timing). To enjoy music, be it a film sound track, favourite CD, download, or vinyl to its full extent, it is vital that a system delivers that information accurately. Good timing gives so many insights into the special relationship between musicians. Good timing makes your foot tap.

No cable can improve timing as such, but once again, poor quality cables can have a dramatically negative effect.

Ideally, a system should have an even tonal balance – in other words, it should not emphasise one particular tonal frequency over another. If a system or component does favour a particular tonal frequency range it is often described as coloured.

Cables can and do influence the tonal qualities of a system and research into this has shown that there is an important relationship between the type of conductor and the material used to insulate it. Get this right and it is possible to produce a neutral balance right across the frequency range

A variation on oxygen free copper. Ultra-cast copper is cast then recast to further eliminate impurities. In theory this should make Ultra-cast copper the conductor of choice in all Chord Company products, but despite much experimentation we have yet to successfully produce an analogue cable using Ultra-cast copper.

The area where we have achieved real results with this material is digital signal transmission.   Despite the fact that its a digital signal, the Ultra-cast copper conductors in direct comparison to more conventional oxygen free copper conductors produced a markedly more detailed and natural sound. Although the tonal characteristics of both cables cannot be attributed solely to the choice of conductor material, Ultra-cast copper obviously has a marked influence.