Audio Power Distribution

TimMc

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This is an M32 and is running to the box and with some Dante all on UTP. I used to run data cable as a high school gig and they very rarely spec'd STP for any runs unless it was going over something that would absolutely cause interference or the client paid for the extra cost. Or if there was an issue with an installed cable dropping a lot of packets. With IP based data it's not so much of an issue unless you start having signal problems since the twisted pair tends to help reject interference as I understand it, but I don't know what sort of protocol is used in streaming to a stage box since they'll all be proprietary. I'd wager it's some sort of UDP streaming, but I've never experienced signal drop on a digital board to the degree that it manifests in sound issues. That's interesting about the X32 popping problem with the data cable.
AES 50 "supermac" is not TCP/IP data. The only thing in common is the Physical Layer, i.e. the use of 4 pair network data cabling.

The shield is required because Music Group's design is not the same as the original Midas/KT AES50 design used the DL21xx, DL2xx, DL4xx stage boxes (which run happily on UTP) and ESD will cause loss of word clocking between the i/o boxes and the M/X32. Nasty POP, a half second or so of no audio while the clocks sync back up.

In this use the shield has nothing to do with radiated energy escaping the cable or entering it over the run... it's about avoiding the nasty noise and embarrassing interruption.
 
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StradivariusBone

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So this is a DL32 box on stage and we're running the AES50 leg on Cat5e UTP. I haven't had any issues with the clock dropping out, but I admittedly haven't spent much time learning about AES50, so google led me here- http://www.aes-media.org/sections/uk/Conf2011/Presentation_PDFs/07 - Al Walker - Applications in Live Convert Sound.pdf

Interesting stuff! I didn't realize how different from IP this is, I mean beyond the fact that you can't just hook up a Linksys router to it. It uses pairs 3 and 4 for the clock sync, but that PDF doesn't specify anything about using shielded cable. Some more Googling led me to understand that this is a later development? I wonder if just the fact of using all 4 pairs doesn't induce the likelihood of crosstalk as opposed to vanilla IP stuff? I'm guessing this is like running DMX on mic cable, it's a "it works until it doesn't" situation?
 
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TimMc

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So this is a DL32 box on stage and we're running the AES50 leg on Cat5e UTP. I haven't had any issues with the clock dropping out, but I admittedly haven't spent much time learning about AES50, so google led me here- http://www.aes-media.org/sections/uk/Conf2011/Presentation_PDFs/07 - Al Walker - Applications in Live Convert Sound.pdf

Interesting stuff! I didn't realize how different from IP this is, I mean beyond the fact that you can't just hook up a Linksys router to it. It uses pairs 3 and 4 for the clock sync, but that PDF doesn't specify anything about using shielded cable. Some more Googling led me to understand that this is a later development? I wonder if just the fact of using all 4 pairs doesn't induce the likelihood of crosstalk as opposed to vanilla IP stuff? I'm guessing this is like running DMX on mic cable, it's a "it works until it doesn't" situation?
The ESD issue is specific to the Music Group design of the AES50 interfaces in the DLxx/Sxx series stage boxes and the M/X32 consoles. There is a 200+ post thread over at the ProSoundWeb Live Audio Board forums regarding the issue, the research into the ESD and multiple kludges (running separate grounding wires between devices, etc). In the end it comes down to STP, grounding RJ45s and Ethercons that have grounding continuity.
 

StradivariusBone

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There is a 200+ post thread over at the ProSoundWeb Live Audio
Some light reading lol! Thanks for the insight, I'll check it out.
 
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FMEng

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I doubt the Space Coast ever has much trouble with static electricity. Humidity tends to prevent that.

If the cable is in conduit or permanent installed, it also isn't generally a problem. The static problem shows up when the cable is run across carpeted floors, gets walked on or rolled over, or gets mechanically abused.
 

StradivariusBone

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I doubt the Space Coast ever has much trouble with static electricity. Humidity tends to prevent that.

If the cable is in conduit or permanent installed, it also isn't generally a problem. The static problem shows up when the cable is run across carpeted floors, gets walked on or rolled over, or gets mechanically abused.
That might explain most of why this is news to me. It's in an underfloor conduit that is mostly empty (shared with a Dante run and a DMX run) and we get static electricity here for about a week in February when the humidity goes slightly under 80%.
 
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TimMc

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I doubt the Space Coast ever has much trouble with static electricity. Humidity tends to prevent that.

If the cable is in conduit or permanent installed, it also isn't generally a problem. The static problem shows up when the cable is run across carpeted floors, gets walked on or rolled over, or gets mechanically abused.
Putting the UPT in conduit has no effect on ESD as it enters the system via the chassis of either console or stage box - think of the bass playing walking across his nice rug to the "bitch mic" to talk to the Monitor Engineer and getting a little static shock and the POP and sync loss happens. This is a real circumstance (was there, witnessed it). Nobody on the CAT cable, no foot traffic, etc. The loss of clock sync when the cable is stepped on is a different failure mechanism and not related to the ESD issue.
 

StradivariusBone

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Putting the UPT in conduit has no effect on ESD as it enters the system via the chassis of either console or stage box - think of the bass playing walking across his nice rug to the "bitch mic" to talk to the Monitor Engineer and getting a little static shock and the POP and sync loss happens. This is a real circumstance (was there, witnessed it). Nobody on the CAT cable, no foot traffic, etc. The loss of clock sync when the cable is stepped on is a different failure mechanism and not related to the ESD issue.
So in that circumstance the static discharges along the mic cable to the console and the chassis of the device? And it propagates into the AES cable along the clock pairs in absence of a properly grounded shield? I'm not an electrical engineer, but it would seem like there should be a way to prevent that. I'm not too far into that ProSound thread though, sorry if it's answered there. I'm just really fascinated by this failure mode.
 
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TimMc

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So in that circumstance the static discharges along the mic cable to the console and the chassis of the device? And it propagates into the AES cable along the clock pairs in absence of a properly grounded shield? I'm not an electrical engineer, but it would seem like there should be a way to prevent that. I'm not too far into that ProSound thread though, sorry if it's answered there. I'm just really fascinated by this failure mode.
The exact electronic cause (or failure) is not explicitly documented but it relates to the design of the grounding of the AES50 interfaces... no other Midas i/o product or Midas console exhibits this problem... only the DL16, DL32, S16, S32 stage boxes and the M or X32 mixers.
 

StradivariusBone

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I might have to crack mine open and look at how they laid out the board around that interface connection. This is really wild. I'd never heard of this before, but am new to the world of X/M32. I wanted to get a SQ7 lol. Thanks again for the information and the history!
 
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StradivariusBone

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I'm most familiar with the A&H digital boards and really like them and how they structure their workflow. I've got to say though, the M32 has grown on me. It's definitely a bit more rigid and utilitarian in some ways, but it still gives you a lot of features for the price and sounds about as good as the GLD I use at my main gig. I think the occasional hate thrown at these boards is somewhat unwarranted. It's a solid tool for the application.

Here's a question- The M32 Live seems to be only different from the vanilla M32 in superficial appearance and the fact that you get that interface card bundled with the console. Is there any difference regarding this AES static thing? I'll be interested to see if we eventually start having the ESD problem. Humberto just pulled all the humidity out of the state and as I left my house this morning I was greeted by what we call "fall" in Florida. It was still in the upper 70's despite being after sunrise and I wasn't immediately drenched after the short walk down my driveway from the humidity. Also there was a slight breeze that didn't feel like an old man yelling in my face. Static may well be incipient.

And sorry to OP and all for this thread hijack. I hope it's an interesting enough rabbit hole to warrant the side-jog.
 
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FMEng

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AFAIK, both consoles are the same in terms of the AES50 interface. The M32 has better faders and slightly different preamps. "Live" simply bundles the multi-track SD card recording. It would be nice if they were more clear about that in the marketing.
 

TimMc

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I'm most familiar with the A&H digital boards and really like them and how they structure their workflow. I've got to say though, the M32 has grown on me. It's definitely a bit more rigid and utilitarian in some ways, but it still gives you a lot of features for the price and sounds about as good as the GLD I use at my main gig. I think the occasional hate thrown at these boards is somewhat unwarranted. It's a solid tool for the application.

Here's a question- The M32 Live seems to be only different from the vanilla M32 in superficial appearance and the fact that you get that interface card bundled with the console. Is there any difference regarding this AES static thing? I'll be interested to see if we eventually start having the ESD problem. Humberto just pulled all the humidity out of the state and as I left my house this morning I was greeted by what we call "fall" in Florida. It was still in the upper 70's despite being after sunrise and I wasn't immediately drenched after the short walk down my driveway from the humidity. Also there was a slight breeze that didn't feel like an old man yelling in my face. Static may well be incipient.

And sorry to OP and all for this thread hijack. I hope it's an interesting enough rabbit hole to warrant the side-jog.
AFAIK, both consoles are the same in terms of the AES50 interface. The M32 has better faders and slightly different preamps. "Live" simply bundles the multi-track SD card recording. It would be nice if they were more clear about that in the marketing.
There are other, component level differences. The German publication Production Partner did testing to compare, then opened them up for a look. A bunch of stuff is the same but some others are brand specific. It's more than the packaging.
 

jonliles

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That might explain most of why this is news to me. It's in an underfloor conduit that is mostly empty (shared with a Dante run and a DMX run) and we get static electricity here for about a week in February when the humidity goes slightly under 80%.
Davenport is at 65% right now. Down right desert like for that part of FL
 
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