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I need some way to be able to lie down in bed and watch stuff on my PC without disturbing people in other rooms. I have looked into wireless headphones, but am concerned about static issues, having to charge them, etc. I then began looking into 3.5mm audio cable extensions for my wired headphones. I am looking at a 12 foot extension cable on Amazon. The headphones I have now do just fine for gaming, TV, etc. and their cable is about 4 feet long.

Are there any electrical issues I should be concerned with? I vaguely recall something from a transmissions line web course that I took about the importance of impedance matching to minimize reflections (and thus sound distortion?)...

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At audio frequencies, transmission line effects will not be noticed. Maybe if the cable was several km long then yes but, this would be a ridiculous length for a headphone cable.

It is the wavelength that is important and at 20,000 Hz the wavelength is 15 km. A general rule of thumb (in avoiding reflections) is that cables can be unmatched providing the length does not exceed one-tenth of a wave length - that's 1.5 km however, the signal amplitude would be so small at this length that it wouldn't make any difference.

Lower frequencies have a longer (less "problematic") wavelength.

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  • \$\begingroup\$ Yes. But avoid cables that are way too thin, because voltage drop needs to be compensated by cranking up the amplifier, potentially increasing the distortion. \$\endgroup\$ – Dampmaskin Dec 26 '16 at 15:47
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    \$\begingroup\$ @Dampmaskin If the cable is that thinn, it would break due to any mechanical handling anyway. \$\endgroup\$ – winny Dec 26 '16 at 16:52

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