Electronic – Possible cons of excessively long microphone cable (XLR)

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I'm very new to this page and anything electrical in general. I considered putting this on the music SE page but I thought this site may prove more helpful.


I have a small personal "studio" (put very lightly) for recording my own music as a personal hobby. I have a mic hooked up through to a vocoder synth through 2 XLR cables, as my mic uses a phantom power supply. The total distance from the mic to the synth is about 6 feet, but the smallest XLR cables I have are 25 feet and 10 feet, respectively.

My question(s) are thus:

If I coil up the excess slack in my XLR cable, will I experience unwanted interference (either from the loops or the unneccesary length of the cable)? Does this apply to any audio-carrying cable?

Would buying 2 shorter XLR cables give me a cleaner signal than keeping my current ones?

Best Answer

An XLR cable is a "balanced" cable type, which means that it is inherently noise-canceling. For the most-part anyways (nothing is perfect.)

It achieves this by not just sending one signal down the cable, but sending two identical signals - except that one is electrically reversed or opposite from the other. This is called a "differential" mode - when one wire goes positive, the other goes negative. This is beneficial because any extraneous noise that is picked up by the cable is picked up evenly by both wires. This "common-mode" noise is easily rejected.

So long story short, no, a hundred feet of XLR cable probably will make little difference in noise. The signal strength might be reduced slightly due to singal losses, but it should not be noisier because it is long.

That said, XLR cables are great at eliminating the E part of EMI - Electro-Magnetic Interference - or things like radio waves, the "usual" sources of interference. But they are not as good at rejecting the M part - magnetic interference. Luckily, few things produce a magnetic field large enough to be concerned about, so unless you have this cord wrapped around a vacuum cleaner, it shouldn't be a problem.

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