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[Darin Ulmer]

Last night we had an unexpected issue with a pair of X32's on show 7 of a ten show Christmas tour and was wondering if anyone else has experienced this.

We have one X32 at monitor duty and another one at FOH connected via Cat 6.  We powered up around 2:30 with no issue, sound check at 6:15-7:00; no problems.  Then during pre-show playback, with only an iPod playing and then also with the iPod muted, we experienced what sounded like a gun shot through the PA.  It happened three times over a half hour but not with any regularity.  Also, the output meters on the FOH console did not peak; some channels did but they were all muted.  Thankfully this did not happen again until after the  2 1/2 hour show but did again during post show playback.  Again, the only thing open was the iPod playback which came into the FOH console locally while all other inputs came through the Cat 6.

I would describe the sound as somewhat digital in tone.  By that I mean it had a different tone to it than someone turning off a console while the PA is powered up or the sound of unplugging a phantom powered mic that was open.  It did not show up in the monitors and all feeds to the PA and monitors came from the monitor console outputs.  The PA was the houses but the consoles were ours and we were running straight into the house amps.

Anyone experience something like this?

[Corey Scogin]

This exact thing has been discussed at length on this mega-thread:
http://forums.prosoundweb.com/index.php/topic,143428.50.html

It boils down to the following recommendation:
Use Shielded Twisted Pair CAT5e (or better) with Ethercon connectors.

That last part is very important.  The issues are caused either by static discharge or by cable movement.

What cable are you using?

[Darin Ulmer]

I don't have the cable with me but I know it uses the Ethercon barrel connectors. Using this same cable all summer long with two S16 stage boxes and never a problem.  And have not had an issue for six shows and two days of rehearsal on this run.  If it is not fully shielded is it more susceptible to power issues?

[Tim McCulloch]

I don't have the cable with me but I know it uses the Ethercon barrel connectors. Using this same cable all summer long with two S16 stage boxes and never a problem.  And have not had an issue for six shows and two days of rehearsal on this run.  If it is not fully shielded is it more susceptible to power issues?

Yes, the cable must be shielded with the drain wire soldered to the RJ45, and the RJ45 grounding through the Ethercon.

Follow the links Corey provided to find out what testing was done and the conclusions reached.

[Josh Millward]

I don't have the cable with me but I know it uses the Ethercon barrel connectors. Using this same cable all summer long with two S16 stage boxes and never a problem.  And have not had an issue for six shows and two days of rehearsal on this run.  If it is not fully shielded is it more susceptible to power issues?

No, not power issues. The problem is with static discharge. When it gets colder and dryer static becomes more of a problem. It may have finally become cool and dry enough in whatever venue you were in last night to cause a problem. You will note that when people stopped moving around there was no problem, then when they started moving around again to leave after the concert, there was a problem.

I'm betting that your interconnect cable is not shielded, and if it is shielded it is not terminated correctly on one or both ends.

[Darin Ulmer]

No, not power issues. The problem is with static discharge. When it gets colder and dryer static becomes more of a problem. It may have finally become cool and dry enough in whatever venue you were in last night to cause a problem. You will note that when people stopped moving around there was no problem, then when they started moving around again to leave after the concert, there was a problem.

I'm betting that your interconnect cable is not shielded, and if it is shielded it is not terminated correctly on one or both ends.

That makes sense.

[Darin Ulmer]

If the cable is not shielded would it help to use one of the unused wire pairs as a connection between the two connectors as a temporary aid?  This is based on the assumption that not all the conductors are being used in the cable.  If so obviously this wouldn't work.

[g'bye, Dick Rees]

I've done an end-run around the static electricity problems with analog systems in a couple of churches by adding chassis ground wires to drain off the build-up to the nearest ground.

[Darin Ulmer]

I've done an end-run around the static electricity problems with analog systems in a couple of churches by adding chassis ground wires to drain off the build-up to the nearest ground.

As in running a wire from the Ethercon barrel to the electrical ground or just from the X32 chassis to an electrical ground?

[g'bye, Dick Rees]

As in running a wire from the Ethercon barrel to the electrical ground or just from the X32 chassis to an electrical ground?

When I said "chassis", that's what I meant. 

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