E&OE Copyright 2010-
Audio Myths: Silver Wire sounds bright
Above: Silver wire in loose cotton insulation
Audio Myths: Silver Wire sounds ‘bright’
This is one of those persistent myths that is frustrating yet ultimately has a basis in truth.
Good quality pure silver wire in its raw state sounds wonderfully transparent and lucid. Compared to copper it simply appears to have less character -
So where does the bright reputation of silver come from?
Firstly many so called silver cables are actually silver plated copper and in my experience these invariably do have a brightening effect on the sound and commonly a lack of continuity between the highest registers and the midband. It is this effect that is often blamed on the skin effect -
There are many different types of silver wire, with varying properties including levels of impurities. These elements make a substantial difference to the sound. I only use very pure 99.99% wire in my own wiring but that specification alone is not the only important one, the annealing process (heat treatment leading to softening of the wire with benefits including grain growth) is also critical.
Another aspect was one that I stumbled upon quite by chance. The way the wire is treated during cable construction is remarkably important -
When making speaker cables and interconnects the type of construction, number and diameter of strands are also terribly important, but this is an area I will leave open to your own experimentation to avoid giving away all of my trade secrets.
I’ve left possibly the most important aspect to last. The insulator around the wire! If you look at the properties of various insulators in a text book you will see that apart from a vacuum (which is a little impractical for cable manufacture), air is the best insulator. In terms of man made materials PTFE (Teflon) is the next best. However this is where I will differ from many (but not all cable manufacturers). Silver wire insulated with PTFE has a brighter and more synthetic sound compared to an air insulator and spoils the tonality of instruments.
Interestingly some firms (most notably Atlas Cables) are successfully using microporous PTFE, which has small air filled voids in it, not entirely dissimilar in theory from using loose fitting Teflon around silver wire, which is exactly what I use for high voltage applications as the wire is almost completely in air, with just one edge touching the plastic. This effect isn’t exclusive to PTFE, all plastics exhibit the same problems to my ear which is why I prefer to use natural materials as insulators (such as cotton) for audio level connections -
Some research in France has been carried out which may go some way to describing this phenomenon, this theory is called ‘Micro Discharge Interface’. This government funded research took place in 1997 and claims there is intermodulation distortion of the audio signal caused by high level ultrasound that occurs during transmission of alternating current signals. It claims the insulator and wire material both appear critical to reduce this effect to a minimum.
I feel that the microphonics of a cable are also remarkably critical and often over looked, but this is something I will perhaps leave for another time.