A DMX Lighting Question.....

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having been involved in the industry though in the red headed step child portion being a DJ working with a few productions and using lighting many of the yrs I cant compare to your education it wasnt an effort to qualify you. I called them DMX lights tongue in cheek as many of them operate stand alone but my point was they have three pin to connect their DMX " Like" Capabilities. Im not truly qualified to debate any of this. However Bens source of information included Doug Fleener who wrote DMX which in this debate seems to rest at the top without an argueable reply am I wrong again?
 
Hahahaha... Yeah, Doug is revered in the industry and he was in on writing the standard, but it had no one author. I too revere his opinion, however in this case it is just that, his opinion. The standard is the standard. *shrugs* Of course manufacturers allow (or sometimes force) us to abandon the standard, so we should do the best we can to maintain the quality of data (I don't even really like to use CAT5 cable, but I will since it is in the spec) just like Ben said.

Good discussion

Mike
 
One request Mike.. please stop calling all 3 pin XLR cables (some are XL actally, but that's another debate) mic cables. Microphones do not have a monopoloy on the use of the 3 pin XL or XLR connector. I don't want to blur the lines any further than we have already here. A 3 pin XLR connector does not meet the USITT Spec, but neither does a 70ohm non-twisted pair inadequately shielded audio cable. Further, SOME mic cables have pin 1 grounded to the chassis... guess what... DMX won't pass on those. SO... let's try to create some distance between XLR, Mic and DMX. They are NOT the same and are NOT interchangeable terms.

I don't want the newbies to be any more confused than we have already made them. Connectors are connectors, standards are standards, and wire is wire. It's the characteristics of each and the combination thereof that make definitions.

Ben
 
NLFX Pro said:
One request Mike.. please stop calling all 3 pin XLR cables (some are XL actally, but that's another debate) mic cables. Microphones do not have a monopoloy on the use of the 3 pin XL or XLR connector. I don't want to blur the lines any further than we have already here. A 3 pin XLR connector does not meet the USITT Spec, but neither does a 70ohm non-twisted pair inadequately shielded audio cable. Further, SOME mic cables have pin 1 grounded to the chassis... guess what... DMX won't pass on those. SO... let's try to create some distance between XLR, Mic and DMX. They are NOT the same and are NOT interchangeable terms.

I don't want the newbies to be any more confused than we have already made them. Connectors are connectors, standards are standards, and wire is wire. It's the characteristics of each and the combination thereof that make definitions.

Ben
Click to expand...

Okay, so we now have audio cables (which are low quality cable with three pin connectors), XLR cables (which are high quality cables with 3 pin plugs), and DMX cables (which are high quality cables with 5 pin plugs). Works for me.

Yeah, there are also mic cables running around with the hot and neutral pins reversed (put one of those on a rig and see what happens!!!).

I can run with a difference between XLR, mic, and DMX cables. With our new definitions, mic cables are NOT okay for DMX transmission. XLR cables are acceptable, but DMX cables are ideal.

Mike
 
Ok so I think I got the juest of what you guys are saying here.... let's bottom line it.

DMX = 5 pin conductors but only 3 are currently in use.

3 pin DMX cable is best if the cable is atleast 100ohm shielded twisted pairs.... vs 70ohm audio wire, which I gather is typical of cheap mic cables.

On short runs using high quality xlr while not recommended can get you buy in a pinch.

It is prefered to use cable specifically designed for 3 pin DMX even if it is exactly the same as high quality XLR....

Do I basically got it?
 
**shakes head**... there is NO such thing as an XLR cable Mike. That is a type of connector. A close cousin to the XL connector. What if I took 16-2 speaker wire and put an XLR connector on it? Is it an XLR cable? It's akin to categorically calling a cable a TRS or cable. TRS is used for balanced line level audio, mic level audio, Stereo unbalanced audio, relay triggers, fog machine remotes, guitar pedal and effects pedals and a whole host of other things. Let's take the XLR out of the equation, you made an issue about it being 3 pin instead of 5 anyway. Use the connector that fits your light.. what's really important is what is BETWEEN the connectors.

Ben

PS - I honestly can't hit this dead horse one more time. You guys do with this thread what you will. LOL.
 
ahhh ok

Cheap XLR to XLR mic cable = Bad for DMX use

High quality XLR to XLR mic cable = sometimes ok but not recommended

3 pin DMX XLR to XLR = Recommended and sometimes cheaper than High quality mic cable from above...

Is that it?

'Cause that is what I've gleaned out of the tech talk.
 
Ok, you guys go get the gloves, no it's not what you're thinking :D:D:D:D:D:D you're going to an autopsy that should loosen you up :D:D:D:D:D
 
jokerswild said:
Ok so I think I got the juest of what you guys are saying here.... let's bottom line it.

DMX = 5 pin conductors but only 3 are currently in use.

3 pin DMX cable is best if the cable is atleast 100ohm shielded twisted pairs.... vs 70ohm audio wire, which I gather is typical of cheap mic cables.

On short runs using high quality xlr while not recommended can get you buy in a pinch.

It is prefered to use cable specifically designed for 3 pin DMX even if it is exactly the same as high quality XLR....

Do I basically got it?
Click to expand...

Except there is no difference between 3 pin "DMX" cable and high quality audio (or XLR) cable.

Other than that you have it.

Mike
 
You are dead on Rob! :)

A good opportunity for a selfish plug:

http://www.northernlightfx.com/platinum

You'll notice that the 22GA 120 ohm DMX cable with foil and braid shield is less expensive than the 20GA 70 ohm 95% braid mic cable. This mic cable is on A-listed tours, it's the "good stuff" Mike was referring to.

Ben

jokerswild said:
ahhh ok

Cheap XLR to XLR mic cable = Bad for DMX use

High quality XLR to XLR mic cable = sometimes ok but not recommended

3 pin DMX XLR to XLR = Recommended and sometimes cheaper than High quality mic cable from above...

Is that it?

'Cause that is what I've gleaned out of the tech talk.
Click to expand...
 
NLFX Pro said:
**shakes head**... there is NO such thing as an XLR cable Mike. That is a type of connector. A close cousin to the XL connector. What if I took 16-2 speaker wire and put an XLR connector on it? Is it an XLR cable? It's akin to categorically calling a cable a TRS or cable. TRS is used for balanced line level audio, mic level audio, Stereo unbalanced audio, relay triggers, fog machine remotes, guitar pedal and effects pedals and a whole host of other things. Let's take the XLR out of the equation, you made an issue about it being 3 pin instead of 5 anyway. Use the connector that fits your light.. what's really important is what is BETWEEN the connectors.

Ben

PS - I honestly can't hit this dead horse one more time. You guys do with this thread what you will. LOL.
Click to expand...

I didn't want to call them XLR cables!! I know XLR is a connector. *pulls hair out* I wanted to call them what they are, high quality audio cables. But you didn't think audio cable was a good term for it. So I guess we "invented" XLR as a term for it? In fact it is audio cable. But it is good quality audio cable.

But it is not DMX cable.

Oh well.

Mike
 
jokerswild said:
ahhh ok

Cheap XLR to XLR mic cable = Bad for DMX use

High quality XLR to XLR mic cable = sometimes ok but not recommended

3 pin DMX XLR to XLR = Recommended and sometimes cheaper than High quality mic cable from above...

Is that it?

'Cause that is what I've gleaned out of the tech talk.
Click to expand...

Almost. Except that #2 and #3 are the same thing.

DMX cable has five pins. Period, end of story.

But you are pretty close.

Mike
 
NLFX Pro said:
You are dead on Rob! :)

A good opportunity for a selfish plug:

http://www.northernlightfx.com/platinum

You'll notice that the 22GA 120 ohm DMX cable with foil and braid shield is less expensive than the 20GA 70 ohm 95% braid mic cable. This mic cable is on A-listed tours, it's the "good stuff" Mike was referring to.

Ben
Click to expand...

No its not. The mic cable I am talking about is 22awg 110 Ohm cable with foil and braid shield.

Mike
 
Esoteric said:
Almost. Except that #2 and #3 are the same thing.

DMX cable has five pins. Period, end of story.

But you are pretty close.

Mike
Click to expand...

:sqrolleyes:How did I just know that was comming.....:sqlaugh:

I think you guys basically agree except on that one point.... I think I would lean with Ben though especially when talking about long runs and lots of fixtures....

I have 4 lights hooked up via 2 "DMX" cables and 2 high quality mic cables... which is ok because it's a short run..... and only 4 fixtures.

Based on this thread I don't think I'd dare a mix of cables for more than say 10 fixtures.
 
jokerswild said:
:sqrolleyes:How did I just know that was comming.....:sqlaugh:

I think you guys basically agree except on that one point.... I think I would lean with Ben though especially when talking about long runs and lots of fixtures....

I have 4 lights hooked up via 2 "DMX" cables and 2 high quality mic cables... which is ok because it's a short run..... and only 4 fixtures.

Based on this thread I don't think I'd dare a mix of cables for more than say 10 fixtures.
Click to expand...

Its fine, you just have to make sure they are 22awg and properly shielded. Like I said, at several of the venues I work at that is their standard for mic cables, so they are interchangeable. I have thousands of the feet of stuff running in rigs. But that is all I buy. But I wouldn't walk into any venue and just grab mic cables. You might end up with the 70 Ohm stuff.

Mike
 
how about considering the details here Mike

Perhaps Im just a DJ. Hard to bash on this however.Heres a homework lesson for you.:sqwink:
https://edeskv2.belden.com/Products/index.cfm?event=printPrev&pnum=9841&ut=english
Esoteric said:
Okay, so we now have audio cables (which are low quality cable with three pin connectors), XLR cables (which are high quality cables with 3 pin plugs), and DMX cables (which are high quality cables with 5 pin plugs). Works for me.

Yeah, there are also mic cables running around with the hot and neutral pins reversed (put one of those on a rig and see what happens!!!).

I can run with a difference between XLR, mic, and DMX cables. With our new definitions, mic cables are NOT okay for DMX transmission. XLR cables are acceptable, but DMX cables are ideal.

Mike
Click to expand...
 
if you took a look it might sink in

1.WHY is there a RS-485 standard to begin with?
2.second, why would Belden make a cable for it if their audio cable 1694A, etc was good enough. Engineering is expensive... why re-invent the wheel ?
3.thirdly, why would they even specify the standard at ANSI or USITT?

why not just say "use any damn cable you feel like"

4.and LASTLY.. why does Belden make a 1 pair version of the RS-485 cable...

This should be more than enough food for thought to sleep on.
 
1. It is an improvement over RS232 which allows more than two units to be connected. Both are serial data transmission. It can consist of one or two pairs (two or four wires).
2. Belden 1694A is a single conductor cable.
3. USITT first specified the standard in hopes that the many proprietary systems that had been in use up to that point would be abandoned for an industry standard. The proliferation of moving lights made this even more necessary than it had been before. ANSI took over the standard and actually made it a "true" standard through ESTA.

You can't use any cable you feel like because you don't want data loss (or data reflection, hence terminators) over the rig. That is why you should never use 70 Ohm mic cable.

4. As far as I can tell, after a little research, RS485 was originally used for motor control applications. This one is hard to find the answer to.

I still don't get the point?

Mike
 
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