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Author Topic: AES50 dropout during subharmonics/anything under sustained 50hz  (Read 1317 times)

Jason Branden

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #30 on: May 16, 2018, 02:25:42 pm »

Just to be clear, and I may have missed this.  You mention patch cables.  Did you have the Cat5 patched directly between the M32 and DL32, or hooked into a rack panel, and then patched to the DL?  I've been told that Midas advises a direct connection between devices.

Yeah, I wasn't very clear about that part.   So I have a "master" snake that has two fiber (10gig Ethernet connections) SDI video cables, DMX cables, and four AES50 cables.  The first night I was using the master snake.  2nd night I ran an independent direct connection between the M32 and the DL32.   Behavior was the same when tested both ways.  -good catch, I hadn't mentioned that!
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Jason Branden

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #31 on: May 16, 2018, 02:28:41 pm »

You mentioned patch cables. Did you check the patching adapters? 


Sent from my iPhone using Tapatalk

Just replied up above about a similar question, but in short, yes. console to DL32 was checked. All pins and ground. (on all AES50 cables) -Then on the 2nd day I used a independent cable that was connected directly between the M32 and DL32.
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Dan Mortensen

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #32 on: May 16, 2018, 03:59:33 pm »

Yeah, I wasn't very clear about that part.   So I have a "master" snake that has two fiber (10gig Ethernet connections) SDI video cables, DMX cables, and four AES50 cables.  The first night I was using the master snake.  2nd night I ran an independent direct connection between the M32 and the DL32.   Behavior was the same when tested both ways.  -good catch, I hadn't mentioned that!

This snake sounds pretty awesome! If you feel like posting pictures, I'd like to see it.

One question: if the master snake has 4 AES50 cables already, why didn't you swap over to one of them? Or were they already in use? Why the need for the totally separate single run snake?

Oh, and is there an AC run in that master snake? Preemptory comment: Having an AC cable in a bundle with AES 50 cables will not have an effect on digital transmission, as long as all cables have twisted-pair construction. I'm just curious how you get your AC to FOH.
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Jason Branden

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #33 on: May 16, 2018, 08:25:58 pm »

This snake sounds pretty awesome! If you feel like posting pictures, I'd like to see it.

One question: if the master snake has 4 AES50 cables already, why didn't you swap over to one of them? Or were they already in use? Why the need for the totally separate single run snake?

Oh, and is there an AC run in that master snake? Preemptory comment: Having an AC cable in a bundle with AES 50 cables will not have an effect on digital transmission, as long as all cables have twisted-pair construction. I'm just curious how you get your AC to FOH.

The "master" snake has been a work in progress for a bit. Having a custom cable made would of been insanely expensive so I end up building it myself. I've been adding lines to it as needed but Its finally hit its maximum. I don't think I could squeeze one more line into it.  -I was looking though my phone and found a pic of the non-completed version of it that I sent as a text message to someone a few years back while building it. Not the best quality pic, and not its current state, but it'll get the idea across. Its since had its cover pate installed and as been finished with proper connectors, more lines, etc  Its about 150ish feet on a rolling cable reel. (see pic below) Perfect for the indoor events I've been doing. Its also since been finished off with a hubble connector on the FOH side that has everything laid out nicely for patching.  This snake doe NOT have any power running in it. Its completely low voltage.  FOH gets its power from a five wire cable that has 30A of three phase on it. (enough for lighting world, video world, audio, etc) It works out to be about 30 amps per department, off the sub distro. Which is complete overkill generally but I'd rather have more than enough for breathing room. (the extra has come in handy for spotlights, long throw video projectors, and other random things)


As for the other AES50 lines, they were in use at the time for some other task so I was unable to leverage them for testing. When I ran into trouble, I wanted to run directly between the M32 & DL32 which I would not of been able to do going though the snake. When I ran the spare it had no patches or connectors in the middle so I was able to rule out a few things on that front. It seemed like a good place to start while in a panic during the event ;)


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Dan Mortensen

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #34 on: May 17, 2018, 07:18:23 pm »

The "master" snake has been a work in progress for a bit. Having a custom cable made would of been insanely expensive so I end up building it myself. I've been adding lines to it as needed but Its finally hit its maximum. I don't think I could squeeze one more line into it.  -I was looking though my phone and found a pic of the non-completed version of it that I sent as a text message to someone a few years back while building it. Not the best quality pic, and not its current state, but it'll get the idea across. Its since had its cover pate installed and as been finished with proper connectors, more lines, etc  Its about 150ish feet on a rolling cable reel. (see pic below) Perfect for the indoor events I've been doing. Its also since been finished off with a hubble connector on the FOH side that has everything laid out nicely for patching.  This snake doe NOT have any power running in it. Its completely low voltage.  FOH gets its power from a five wire cable that has 30A of three phase on it. (enough for lighting world, video world, audio, etc) It works out to be about 30 amps per department, off the sub distro. Which is complete overkill generally but I'd rather have more than enough for breathing room. (the extra has come in handy for spotlights, long throw video projectors, and other random things)


As for the other AES50 lines, they were in use at the time for some other task so I was unable to leverage them for testing. When I ran into trouble, I wanted to run directly between the M32 & DL32 which I would not of been able to do going though the snake. When I ran the spare it had no patches or connectors in the middle so I was able to rule out a few things on that front. It seemed like a good place to start while in a panic during the event ;)




Thanks for posting the pic. It looks like a nice project.

Is there an Ethercon cable we're not seeing? I'm not recognizing any of those connectors as being an Ethercon, but I just might not be seeing it from the side like that.

If there's not one, it could have been that the DJ had some kind of static electricity discharge (ESD) that was causing your lack of sync periodically. Sparking to anything connected to your snake head (like a mic or DI) can result in loss of sync when you don't have Ethercons and shielded cable throughout. Even though Midas officially says you don't need STP, I've caused sync disruption in a Midas console (Pro 3) in tests using UTP.

Just one more possibility.
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gertsanner

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #35 on: May 19, 2018, 11:18:59 pm »

There are a few quirks with AES50 that not everyone realises because its not very obvious.
On AES50 the word clock travels on the extra 2 pairs of the RJ45 Cable. One pair will do send and the other will do receive. The data travels on the other two pairs inside a the network cable. Thats why AES50 needs all 8 pins on a network cable. However, which pair does receive and and which one does send is determined by the system as it starts up. It is a bit random. Should now one of the pairs be damaged the fault will only become obvious when the direction on clock and the damage coincide. ( Hope this makes sense so far ). Thats why often people will report that it was working fine one day and not fine the other, and then go back to be fine the next job. So that is your first thing you could check. A regular CAT5 tester will often not do, as it will only check the inner two pairs as that is all that is required by ethernet.
The next thing to really look out for is that when you use none Ethercon connectors it is possible to bend the outside pins of a socket on either the console or the stage box by inserting the RJ45 not 100% straight. Should that happen the socket needs to be replaced. And this will manifest itself with word clock issues like you describe.

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Russell Ault

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #36 on: Yesterday at 06:43:40 pm »

A regular CAT5 tester will often not do, as it will only check the inner two pairs as that is all that is required by ethernet.

A slight correction: Gigabit Ethernet uses all four pairs in a Cat5e (or above) cable. 100MB Ethernet only uses two pairs, but it's the second inner pair and one of the side pairs (i.e. pins 1, 2, 3, and 6).

In my mind, the reason that most inexpensive Ethernet testers don't work well is because they typically only run a continuity test (i.e. testing whether the cable will pass D.C.), and there are lots of things you can do to a cable that will make it pass D.C. flawlessly but not pass a high frequency signal (like Ethernet or AES50) well (or at all).

-Russ
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Mark Wilkinson

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #37 on: Yesterday at 07:47:17 pm »


In my mind, the reason that most inexpensive Ethernet testers don't work well is because they typically only run a continuity test (i.e. testing whether the cable will pass D.C.), and there are lots of things you can do to a cable that will make it pass D.C. flawlessly but not pass a high frequency signal (like Ethernet or AES50) well (or at all).

-Russ

Thx.   Do you have a recommendation for a good tester, a good value?
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Robert Lunceford

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It is a wonder that they ever incorporated RJ45 connectors in pro audio. Durability is not their strong suit. Not very easy to repair or replace connections/connectors when compared to a XLR or phone plug. It is nice to be able to repair a cable in the field with basic tools and skills.
Troubleshooting a bad cable also seems to be problematic.
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