DMX or XLR cable. Does it matter?

I know I've used regular ole' XLR cable for my lighting and it seems to be okay.

However, can someone use DMX cable for connecting to active speakers?

I want to buy two(2) 20ft cables to be used for either my lighting, or my sound.

Which should I buy? DMX or XLR cables.?? And, where is the best pricing? I see professional 20ft XLR cable on Ebay for $5.95.

Yes it does matter.

DMX cables are designed to carry data, xlr are designed to carry audio.

data cables carry info faster, and are made from better wire, and have a different resistance rating than regular ol xlr's.ld

you would notice a difference in programming intelligent lights, i have seen glitches just dissapear.........

So.... I can use XLR cables for lighting. It's just not ideal.

But.... I can't use DMX cables for audio?

What would happen if I accidently plugged DMX cable into my mixer and powered speaker?

I use dmx to the tree from the controller, simply because it's a long run....between fixtures; xlr.....No real issues...

IMHO....

Ask Ben @ NLFX. I'd trust his response.

Just my 2 quid...

Dang!! I just bought two (2) 20 ft xlr's on ebay for $20 delivered. I hope they are okay. Worse case is I can use them for my speaker run.

They'll likely work....

There are special cables designed for the 5 pin variants... But most of the time standard canare cable will do the trick... Don't let companies fool you into getting DMX cable instead of regular XLR cable.

There are special cables designed for the 5 pin variants... But most of the time standard canare cable will do the trick... Don't let companies fool you into getting DMX cable instead of regular XLR cable.

I have to take issue with you Travis. Whereas the USITT requires a 5 conductor cable, 3 is common. There are substantial differences, critical even, between digital DMX cable (RS-485) and standard audio mic cable. The two critical differences are in the impedance of the cable and the sheilding. DMX cable is 110 or 120 ohm whereas standard audio cable is 70 ohm. Also, because it is a balanced digital cable (where pin one is NOT tied to the sheild and connector housing) you will typically find the data conductors (pins 2 & 3) twisted, just like in an ethernet cable. This is done to provide common mode rejection where noise reaches both conductors equally but in opposite phase and is therefore cancelled. There is also a "drain" conductor, then typically some outer sheilding (foil, braid or both).

You can use a standard audio cable, and it will work (sometimes), but it is CLEARLY not recommended. The noise inducted, or interference acquired by inadequate cable can permanently damage fixtures, particulary the demuxer chips. I have seen this too many times to recount. Further, the impedance issue causes data reflections, which at best case are annoying because your fixtures do weird things and at worst again cause fixture failure.

It's NOT worth it. Don't drink your Starbucks the day of the gig, use the savings to buy the right cable. ;)

Ben

So.... I can use XLR cables for lighting. It's just not ideal.

But.... I can't use DMX cables for audio?

What would happen if I accidently plugged DMX cable into my mixer and powered speaker?

It would likely work just fine, I've admittedly done it several times in a pinch. The only issue here is grounding. Pin one is not grounded on a DMX cable. Remember, electricity always takes the shortest path to ground, just make sure it's not you. ;)

There is an unfortunate story of a pastor who was electrocuted using a microphone while conducting a baptism. The mic was properly grounded, but the baptismal pump was not. Point being, the audio signal cable is still part of the electrical system for the building. Proper grounding and bonding can save your life.

Ben

Ben, I remember reading that somewhere, prosoundweb possibly? Some trade magazine?

Ben, I remember reading that somewhere, prosoundweb possibly? Some trade magazine?

The pastor story? I don't recall where I read it... actually I think it may have been discussed during continuing education for my electrical license. Honestly don't recall. Sorry.

Ben

Wow! I have indeed learned something new today from this forum. I never realized that there was a difference between DMX and XLR.

Now that it is established that there is...

can anyone tell me how I can determine which of my many cables are DMX and which are XLR ? :sqeek:

Wow! I have indeed learned something new today from this forum. I never realized that there was a difference between DMX and XLR.

Now that it is established that there is...

can anyone tell me how I can determine which of my many cables are DMX and which are XLR ? :sqeek:

Yes, sorta. LOL. Look at the jacket on the outside. Best case it will either say Belden RS-485 or DMX in some language. However, we see a lot of the "import" cables saying things like "digital laser", etc. If it says "digital" in any form it's probably okay. Likewise, if the cable says "low noise audio" or "mic" or "audio" it probably is not DMX. There are a few exceptions and it can be as clear as mud. If you're really stuck, take a good closeup pic of the jacket on the cable (printing or embossing) and post it. I'll take my best shot at it, and the other experts will chime in as well I'm sure. :)

Ben

Thanks Ben.

I knew the ohm ratings were very different, but i didn't remember the exact numbers, and didn't want to post incorrect info. Thanks for clearing this up for those that don't know.

Thanks Ben.

I knew the ohm ratings were very different, but i didn't remember the exact numbers, and didn't want to post incorrect info. Thanks for clearing this up for those that don't know.

No problem. It's great for us geeks to feel useful and loved. ;)

Ben

Tune in tomorrow for Ben's sale on DMX approved cables!!! lol Seriously, thanks for the info. I was under the assumption that they were basically the same and know I know that is not the case.

Ben, just picked up my new HZ-1000 hazer in Blaine, WA, thanks! I'll test it out this week and report back!

I've only ever used regular XLR cables, never noticed any problems, but most of the time the runs are short. I think the longest run I've ever had was about 60ft and that was to a 4 chn dimmer pack with par cans, so not much to go wrong there. If you are going to run long distances to complex lights I would invest in some real DMX cables.

I'd go about 30 feet and run a couple of LED pars and a couple of PocketScans. That's it. I bought a terminator too.