Originally Posted by StanD
Originally Posted by castleofargh
I remember reading something about a stock cable for westone or shure that was above 3ohm. but it was by choice.
I understand that shielding will increase the cable impedance, but I have no idea in what proportion.
Don't know why they'd purposefully increase the resistance. Increasing the shielding shouldn't increase the impedance. It may actually decrease the resistance of the ground return if that's done by the shielding. It might also increase the capacitance which decreases in impedance as the frequency increases (reactance) and effectively forms a high frequency roll off or if the numbers are right, rolls off treble or even starts lower in frequency. In a different circuit you can do the opposite with a capacitor and roll off bass, which is not the case with cables.
I can't really find anything with real life exemples and values, and formulas often get too complicated for a dude who stopped school 15 years ago and math/physics even sooner ^_^.
all I can find talks about high freqs as in radio freqs, but nothing simple or really relevant to my eyes (meaning: that I can understand) in the audio range.
I was thinking about an increase in impedance from shielding like this:
signal in the cable generates magnetic fields that will create a signal in the the shielding material that will itself create back magnetic field that should in the end oppose voltage in the cable in some ways no? I don't know if this super inefficient transfert can matter at all, but as it depends on ... voltage?(I'm guessing it's voltage for magnetic field) ... the changes arent linear and might matter in some ways. I just have no idea about the values of such effect.
also what I really know nothing about is how the shielding material behaves on portable stuff (like IEM cable) where it's etheir not grounded at all, or linked to the circuit ground of the cable itself? I really don't know much about all this, but my little pinky told me proper shielding shouldn't be like that.
and about the cable with a few ohm, again from a very insecure memory, I believe the purpose was to make a little change in signature thanks to the weird impedance/freq caracteristics, to ease up on a given frequency range. I guess it was a situation not unlike the W4 where the signature is almost an exact opposite of the impedance graph and adding resistance tend to make the sound flatter(not taking damping into account).