gutten pisze:
Sebba
Dzięki za linki do Guardiana, posłałem dziś maila do pana Bena Goldacre'a z uwagą, że nie odrobił pracy domowej przed napisaniem felietonu.
A i ja cos tez napisałem, choc ten temat to strata czasu,
In the Technology section of your magazine you published an interesting article about power audio cables. The audio industry is actually full of such examples where products based on pseudo-science are offered in ridiculously high prices, and audiophiles especially those with less technical knowledge spend fortune believing that a new cable or silver fuses improve the sound quality of their system.
Being myself an engineer and a music lover, I can honestly say that if any mains cables are properly designed i.e. according to the circuit theory, and they are properly made, connected and shielded, they cannot affect the sound quality in any way. It is like nobody would notice if someone took a glass of water out from the ocean.
The purpose of a mains cable is to connect the power supply in an electronic device with a power socket on the wall to provide the energy necessary for its working. Thus, the cable and the plugs should be of the proper gauge, the connectors have to be reliable, stable and clean. Bad connectors can spark and generate a lot of wide-spectrum noise but this happens rather rarely and in high-current networks.
The extra shield which is found in almost all audio power cables, as well as small ferrite beads, might lower the RF noise but very small capacitance and inductance limit such filtering to only very high frequencies. Of course the power noise cannot be ignored and should be suppressed in a properly designed power supply by implementing capacitors, chokes, shielded transformers and proper grounding. Practically, a simple LC filter will work much better than a Ł1000 silver audio-dedicated mains cord ! I mean technical parameters, not what happy owners will hear, which often has nothing in common with reality.
It is also pointless to use very expensive external filters (called “conditioners”) which make the 50Hz sine wave almost ideal with very low harmonic distortion. Why it won’t work ? Simply because in every power supply there is a device which again distorts even a perfect sine wave and produces a lot of THD. It’s an unlinear device called…. rectifier, necessary to turn AC into DC.
Of course I do not negate the importance of low noise power supplies in audio systems as they directly affect the sound but this should only be achieved by the proper designing, filtering, layout, and grounding inside the equipment, not by power cables.
So why so many people still believe that power cables improve the sound quality? I’ve come up with two explanations: technical and psychological.
If an external mains cable with a RF filter indeed improves the sound, it means the equipment has been badly designed, and the power noise gets into the signal circuits so this extra filtering lowers the noise in amplifiers or jitter digital audio. But this seems rather unlikely.
Most customers have little or no technical or scientific knowledge, and even more educated people are often taken in by pseudo-scientific hype. Marketing is about selling dreams and many of us believe that if we buy some products, we are going to be happier, healthier, more beautiful, the music will be warmer, softer, faster etc. And, surprisingly, the more expensive product, the better demand for it. In economic science this phenomenon is called the Veblen paradox.
So why not sell, for example, special expensive power cords for computers? Any computer with a silver mains cable would certainly work faster, the pictures would look more lively, sharper. Printers would work faster and consume less ink, and even the calculations, especially floating point calculations, would be far more accurate.
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