Je suis certains que beaucoup se posent ou se sont posés la question de savoir quel diamètre de câble nous avons besoin pour nos installations.
Le tableau ci dessous est de nature à vous donner de bonnes indications.
Ces calculs n'ont finalement que peu de sens dans les applications audio.
Ces chiffres sont élaborés à la température de fonctionnement du câble, en toute sécurité (T(sec) est normalisé), lors de l'application d'un courant continu stable, pendant t minutes (t(ref) étant normalisé).
Le fait est que les signaux audio sont dynamiques avec des pics d'énergie, des câbles de 1,5mm et 3mm peuvent résister à de forts courants de pointe instantanés de plusieurs centaines d'ampères. En application audio,un câble de 1,5mm serait à l'aise en permanence à la transmission d'un son sinusoïdal de 1KW d'onde.
Je n'ai pas tout traduit l'article par manque de temps, je vous laisse la suite en Anglais. Il y a un passage très intéressant sur les délais et la perception auditive...
These current capacity calculations become somewhat meaningless in audio applications because the figures relate to the safe operating temperature of a cable when it heats up after a period of time (minutes) when carrying continuous steady current.
The fact is that audio signals are dynamic with peaks of energy, and 1.5 and 3mm cables can withstand high instantaneous peak currents of several hundreds of amps. However, even high power audio systems, say 1000watts into 8 ohms, would only draw 11 amps RMS- so theoretically the Monitor cable would be comfortable continuously driving a 1KW sine wave sound.
For high end audio applications the limiting factor is not the current capacity of a cable. Ohms law, (resistance) does of course still apply, but there are other factors that cause energy loss and delay. BUT increasing the amount of conductive material without increasing time delay does allow instantaneous peaks of current to arrive at the destination efficiently and with less delay. I can’t think of a good analogy except a pulse of water getting to its destination quickly and with instantaneous impact if it travels through a larger pipe.
The importance of energy getting through the conductors with minimal time delay AND with the same minimal time delay to all the audio frequencies is critical for image and musicality. Although hearing is sensitive (at best) from 20Hz to 20Khz, the brain can differential time difference that a sound reaches each ear by as little as 2 millionths of a second. This is the kind of timing shift the ears experience when something moves around 5 degrees in front of person about 20m away (do the maths using Pythagoras’s theorem). This is deep in our ‘flight of flight’ evolution and is how we derive position and distance of a sound source. An extended illustration of this is that some owls can hunt and find a mouse if blindfolded – their brains differentiate to about ½ millionth of a second to derive incredibly accurate directional information at a distance!
The implication is, of course, if cable or components cause inconsistent delays to different frequencies, then good imaging is lost;- that is when a system losses its beauty and sounds like two loud speakers with a flat lifeless plane of sound in between them. Another characteristic of poor cable is that voices don’t sound real – this is because the human voice has many harmonics and different, shifting frequencies, and so the result of delaying different frequencies by different times is catastrophic to the realism and smoothness.