Can you use a mic cable to run a DMX signal? The short, and only correct answer is “no”.
Here are the physics. A DMX signal is a digital signal comprised of 1s and 0s being transmitted at a rate of roughly 250,000 per second. Each piece of binary data must remain legible to the receiving end, or the data is no longer useful. 1s must remain 1s and 0s must remain 0s, and they must arrive with the correct timing. Thus, a cable is designed with the electrical characteristics ideal for this type of signal (capacitance and impedance most notably) and it then must be properly protected with appropriate shielding.
This does not mean that a DMX cable is superior and should then be used for both DMX and analog audio. Here again, analog audio cables are designed with the best set of electrical characteristics for that type of signal. High quality analog audio cables usually have larger conductors too.
Beyond that, all cables are not created equal. There is definitely no free lunch. Unfortunately, price isn’t always a good indicator either. A cheap cable can safely be written off as cheap. But taking a cheap cable and charging a lot more for it doesn’t make it a better cable. Look at the specs. As long as the specs are from a meaningful source, they can be a valuable tool. Be wary of things that look too good to be true of course, and if they don’t have specs… I would simply move on to the next cable. Why buy something when you don’t know what you’re buying??
Here are some example specs from NLFX Professional Platinum Series cables. You can clearly see the different electrical characteristics:
For Platinum Series DMX Cable:
- 22 AWG 19 strand Annealed Tinned Copper
- DC Resistant -14.7 Ω / Mft @ 20º C
- Impedance – 110 Ω / Mft +/- 10%
- Capacitance – 12.00 pF / ft +/- 10%
- Aluminum Mylar shield – 100% coverage
- Tinned Copper Braided shield – 85% coverage
For Platinum Series Mic Cable:
- 20 AWG – 26 strand Annealed Tinned Copper Conductors
- DC Resistant -10.6 Ω / Mft @ 20º C
- Impedance – 72 Ω / Mft +/- 10%
- Capacitance – 21.2 pF / ft
- Cable drain 19 strands Tinned Copper
- Tinned Copper Braid – 95% coverage
Now let’s post some pictures of a few different types of cables. Note that the cheap, spirally shielded mic cable has tiny conductors, virtually no shield and that the shield must be twisted into the ground conductor. By contrast, the Platinum Series mic cable has 20 gauge, robust twisted conductors, a tight, thick braid, and a separate ground conductor within it. Then take notice of how different the DMX cable is from either. Most often, when people use a cheap mic cable for DMX they are doing so because it is cheap. Then we end up with a cable that is not only inferior for it’s intended purpose of transmitting analog audio, but also woefully inadequate for the purpose of transmitting a digital signal that it was never intended to be used for.
Spirally shielded inexpensive mic cable
Braid shielded quality mic cable
Braid / Foil shielded DMX cable