Installs Lost our Dressing Room Monitors...

[JVV]

Hello, I do not know enough about sound or the system set up of this Performing Arts Center to get this post right the first time, but hopefully some of you are bored on a Friday Night and want to help me trouble shoot this issue.

We lost the feed to the dressing rooms today. We still have the feed to the booth and in my experience, when the booth has been out, they have all been out due to a patching problem at the mixer. This is the first time that we can hear in the booth but the entire dressing room monitors have been out. I have check all the wall plates in each room and the volume is up.

The schematics that I have for the building show the signal goes from the amp and then splits to the Booth and to a junction box where it splits to the other rooms. My guess is that somewhere a wire feeding that entire half of the building has been damaged? Is there a good way to test that theory? Are there things I haven't thought of yet?

 

[RonHebbard]

Hello, I do not know enough about sound or the system set up of this Performing Arts Center to get this post right the first time, but hopefully some of you are bored on a Friday Night and want to help me trouble shoot this issue.

We lost the feed to the dressing rooms today. We still have the feed to the booth and in my experience, when the booth has been out, they have all been out due to a patching problem at the mixer. This is the first time that we can hear in the booth but the entire dressing room monitors have been out. I have check all the wall plates in each room and the volume is up.

The schematics that I have for the building show the signal goes from the amp and then splits to the Booth and to a junction box where it splits to the other rooms. My guess is that somewhere a wire feeding that entire half of the building has been damaged? Is there a good way to test that theory? Are there things I haven't thought of yet?

@JVV Never having been in your venue I'll ask a few questions:
a; Are you certain your booths and dressing rooms are all sourced from the same single channel amplifier?
b; When your system is working normally, do all speakers hear the same pages / all calls are heard back stage and in the booth??
c; In many systems it's possible to route the same monitor signal to all speakers but to page only back stage without paging the booths risking pages leaking into your audience areas.
d; In systems where it's possible to send different pages to the booths than back stage you often find more than one amplifier or a dual channel amplifier with one channel driving back stage and the second channel powering the booth speakers.
e; Is your monitor / page wiring in conduit??? If so, chances of damage to the wiring is greatly mimized / quite unlikely.
f; Were any contractors working in your walls or ceilings at the time when you lost the feed to your dressing rooms????
Toodleoo! (From north of Donald's walls.)
Ron Hebbard

 

[JVV]

@JVV Never having been in your venue I'll ask a few questions:
a; Are you certain your booths and dressing rooms are all sourced from the same single channel amplifier?
b; When your system is working normally, do all speakers hear the same pages / all calls are heard back stage and in the booth??
c; In many systems it's possible to route the same monitor signal to all speakers but to page only back stage without paging the booths risking pages leaking into your audience areas.
d; In systems where it's possible to send different pages to the booths than back stage you often find more than one amplifier or a dual channel amplifier with one channel driving back stage and the second channel powering the booth speakers.
e; Is your monitor / page wiring in conduit??? If so, chances of damage to the wiring is greatly mimized / quite unlikely.
f; Were any contractors working in your walls or ceilings at the time when you lost the feed to your dressing rooms????
Toodleoo! (From north of Donald's walls.)
Ron Hebbard

Further down the rabbit hole I go....
I thought I had localized the problem, but... On paper the Amp backstage is supposedly powering the Dressing Rooms and the Booth speakers. We realized we were also having an issue with the Lobby feed, and in trying to figure out that Amps situation, we turned the Lobby Amp off and lost the feed to the Booth, so it would seem that the Lobby Amp is also running the Booth. We have always heard all pages to the Dressing Rooms and Booth (but not the Lobby) so somewhere things are routed separately. I just can't trust the paperwork I have from 2007...

The wiring is in conduit until it disappears into the dropped ceiling, then it looks like exposed wires from there.

IT did have some contractors in installing more cameras and were in the Booth prior to loosing signal, but they say they didn't unplug or change anything. I also feel like there is a louder hum in the system this weekend and so we did poke around with the Amps trying to localize the source of the hum...so I don't know if that caused any problems. But now it looks like both the Dressing Rooms and Lobby are offline while the Booth still gets signal. It would appear the hard and soft patch in the mixer has not been changed since the last time it worked.

 

[RonHebbard]

Further down the rabbit hole I go....
I thought I had localized the problem, but... On paper the Amp backstage is supposedly powering the Dressing Rooms and the Booth speakers. We realized we were also having an issue with the Lobby feed, and in trying to figure out that Amps situation, we turned the Lobby Amp off and lost the feed to the Booth, so it would seem that the Lobby Amp is also running the Booth. We have always heard all pages to the Dressing Rooms and Booth (but not the Lobby) so somewhere things are routed separately. I just can't trust the paperwork I have from 2007...

The wiring is in conduit until it disappears into the dropped ceiling, then it looks like exposed wires from there.

IT did have some contractors in installing more cameras and were in the Booth prior to loosing signal, but they say they didn't unplug or change anything. I also feel like there is a louder hum in the system this weekend and so we did poke around with the Amps trying to localize the source of the hum...so I don't know if that caused any problems. But now it looks like both the Dressing Rooms and Lobby are offline while the Booth still gets signal. It would appear the hard and soft patch in the mixer has not been changed since the last time it worked.

@JVV Please keep us informed and we'll play along at home. How many amplifiers are you aware of and how many channels does each amplifier have??
Toodleoo!
Ron Hebbard

 

[RonHebbard]

Further down the rabbit hole I go....
I thought I had localized the problem, but... On paper the Amp backstage is supposedly powering the Dressing Rooms and the Booth speakers. We realized we were also having an issue with the Lobby feed, and in trying to figure out that Amps situation, we turned the Lobby Amp off and lost the feed to the Booth, so it would seem that the Lobby Amp is also running the Booth. We have always heard all pages to the Dressing Rooms and Booth (but not the Lobby) so somewhere things are routed separately. I just can't trust the paperwork I have from 2007...

The wiring is in conduit until it disappears into the dropped ceiling, then it looks like exposed wires from there.

IT did have some contractors in installing more cameras and were in the Booth prior to loosing signal, but they say they didn't unplug or change anything. I also feel like there is a louder hum in the system this weekend and so we did poke around with the Amps trying to localize the source of the hum...so I don't know if that caused any problems. But now it looks like both the Dressing Rooms and Lobby are offline while the Booth still gets signal. It would appear the hard and soft patch in the mixer has not been changed since the last time it worked.

@JVV You mention hard and soft patches; what types of connectors are utilized in your hard patches? XLR's are comparatively solid but still subject to corrosion / intermittent connections due corrosion if / when not un-mated and re-mated a few times annually. Full size ADC broadcast style RTS are less reliable over a similar period of time and bantam RTS jack fields are even worse. @FMEng @Ancient Engineer @MNicolai or @TimMc Care to comment?

 

[RonHebbard]

Further down the rabbit hole I go....
I thought I had localized the problem, but... On paper the Amp backstage is supposedly powering the Dressing Rooms and the Booth speakers. We realized we were also having an issue with the Lobby feed, and in trying to figure out that Amps situation, we turned the Lobby Amp off and lost the feed to the Booth, so it would seem that the Lobby Amp is also running the Booth. We have always heard all pages to the Dressing Rooms and Booth (but not the Lobby) so somewhere things are routed separately. I just can't trust the paperwork I have from 2007...

The wiring is in conduit until it disappears into the dropped ceiling, then it looks like exposed wires from there.

IT did have some contractors in installing more cameras and were in the Booth prior to loosing signal, but they say they didn't unplug or change anything. I also feel like there is a louder hum in the system this weekend and so we did poke around with the Amps trying to localize the source of the hum...so I don't know if that caused any problems. But now it looks like both the Dressing Rooms and Lobby are offline while the Booth still gets signal. It would appear the hard and soft patch in the mixer has not been changed since the last time it worked.

@JVV Good luck in the rabbit hole!
Toodleoo!
Ron Hebbard

 

[Ancient Engineer]

I have a few ideas... I suspect this is a 70V distributed system and not an 8Ohm (er whatever) with L-pads for volume controls...

If it is a 70V system it is pretty easy to trace... use the hound from your fox and hound kit.

Play some moderate volume music over the system.

If the hound gets within 5-15cm of a live 70V cable you WILL hear the music...

So, you can trace out where the signal stops (using your good half-splitting troubleshooting techniques) and repair, etc.

Also... depending on the skill level of the installer... the fully clockwise rotation of a 70V volume knob will 62.7618639% of the time actually be OFF instead of full volume.

So... set your volumes to a mid-point and see if that rectifies the situation as well.



if it is a kludge of non-70V stuff, you are in for a battle.



I once worked at a place that used a McIntosh MC2300 amp for the backstage and booth because it would tap down to .25 (that is 1/4) Ohm impedance and not catch fire.

It was a trainwreck of series and parallel circuits to try to keep the load at the amp something it would tolerate...

Eventually they contracted a switch over to a good 70V system and QSC amps (even though the MC2300 has 70V taps).

The MC2300 (working perfectly) ended up at my home after fishing it from the contractors' dumpster...

 

[JVV]

@JVV Good luck in the rabbit hole!
Toodleoo!
Ron Hebbard

In the booth there is an Amp labeled Front Lobby (which it seems also powers the Booth) and then Amps for Mains LR, (2) for Center Cluster, (2) for Subs and (2) for Stage Monitors which are the onstage wedges. There is an amp in the backstage rack (unlabeled) that supposedly powers the Booth and Dressing Rooms. The back of that amp has 2 channels outputs, one labeled LOB/B RM (which could either mean Lobby/Bathroom (since there are speakers in there) or Booth Room? The other cable is labeled TRM BLK OUT which I can't decipher. It also has a number (A1100) which, on the block drawing looks to go to the Light Control Room. These connections are all wire/screw and covered.

The hard patch in the back of the Sound Console are all XLR and we have unplugged and replugged the Backstage Send to make sure it is secure. But like I said, its being heard just fine in the booth. Even if the Booth is being fed from the Lobby as well (which it must be because when we turn the Lobby Amp off we loose the Booth). We also can hear in the Booth when the Lobby Send is off (not playing in the Lobby at least). And, when I disconnect the XLR for the Backstage Send, we loose the Booth.

Thanks for playing along. (Also, this morning the Show Control computer had switched wireless networks and was not talking to the projector and we lost the ability to mute which we discovered right at the top of the Dress Run. I almost cried, but didn't and figured out the issue.)

 

[Ancient Engineer]

Ugh, I see lifting leads and using your fox to ring out what goes where...

Much less than awesome...


The show computer jumping WiFi for you leads me to General Engineering Axiom #22 which is: Always, always use a hard line for critical paths...


I have an old friend who takes monumental glee in bringing his 9-volt battery powered "wifi disruptor" to venues to watch the chaos ensue. (Kids, this is absolutely a-lot-less-than-legal and I face-palm every time he brings it up.)

This is the same cat that used his lapel-pin IR-LED and a little card to generate every display "off" command on the planet... at the NAB convention.
The look on the stick-figure doing the presentation at the Sony booth when all the screens went ...pffft... was pretty priceless, but seriously, this is a terrible maneuver too.


The point is... run a durn cable to stuff that HAS to work. Especially in a situation where the hardware is just going to sit there. Or... be prepared to have backups for your backups.

 

[RonHebbard]

In the booth there is an Amp labeled Front Lobby (which it seems also powers the Booth) and then Amps for Mains LR, (2) for Center Cluster, (2) for Subs and (2) for Stage Monitors which are the onstage wedges. There is an amp in the backstage rack (unlabeled) that supposedly powers the Booth and Dressing Rooms. The back of that amp has 2 channels outputs, one labeled LOB/B RM (which could either mean Lobby/Bathroom (since there are speakers in there) or Booth Room? The other cable is labeled TRM BLK OUT which I can't decipher. It also has a number (A1100) which, on the block drawing looks to go to the Light Control Room. These connections are all wire/screw and covered.

The hard patch in the back of the Sound Console are all XLR and we have unplugged and replugged the Backstage Send to make sure it is secure. But like I said, its being heard just fine in the booth. Even if the Booth is being fed from the Lobby as well (which it must be because when we turn the Lobby Amp off we loose the Booth). We also can hear in the Booth when the Lobby Send is off (not playing in the Lobby at least). And, when I disconnect the XLR for the Backstage Send, we loose the Booth.

Thanks for playing along. (Also, this morning the Show Control computer had switched wireless networks and was not talking to the projector and we lost the ability to mute which we discovered right at the top of the Dress Run. I almost cried, but didn't and figured out the issue.)

@JVV What would make more sense in terms of amplifiers, proximity to speakers, and wire runs would be: A two channel amplifier in your booth with one channel powering booth monitors and the second channel powering your lobby, assuming your booth is at the rear of your house and in close proximity to your lobby. (Also assuming you want pages in your booth and NO pages in your lobby) Alternatively this amp could provide stereo monitoring in your booth and stereo monitoring in your lobby.
Backstage a second two channel amplifier could be providing monitoring without pages to administration offices on one channel and monitoring with pages and / or pages ONLY for all other speakers back stage. When I first worked at the Stratford Shakespearean Festival the heart of their monitor / paging system was two butch 70 volt amplifiers: One amp powered speakers selected to page only while the other provided monitors with page over-ride and monitors with page only. A relay fed the page only bus whenever the paging mic was keyed and dropped it off whenever no pages were being made. The artistic director and executive producer liked to hear their monitors without any paging interruptions. Equity actors napping on their Equity mandated cots between rehearsal wanted to hear only important pages and not have their slumbers disturbed by performance / rehearsal monitors. It was fabulously convenient considering it was all powered by only two amplifiers back in almost the days of steam power. Thanks for the memories.
Toodleoo!
Ron Hebbard

 

[JVV]

Ummm so.... 15 minutes into the run of Act I, all the dressing room monitors and lobby speakers suddenly started working. The Sound Board op did nothing different. Facilities says no one else is in the building working on anything.

I guess Ill see how long they stay on for....

And yes, I think I will drop a cable down from the projector to the show control computer. Question though... Currently the company that is renting the space is running the sound and projections from the Stage Managers Laptop (Not in QLab, I think its just a Quick Time movie maybe) using the HDMI cable. They are using the house Show Control computer (wirelessly) to shutter the projector when they curtain flies in. Can I have two laptops running the projector, or do I need to install my QLab file onto their computer, or their Quicktime movie onto mine?

 

[RonHebbard]

Ummm so.... 15 minutes into the run of Act I, all the dressing room monitors and lobby speakers suddenly started working. The Sound Board op did nothing different. Facilities says no one else is in the building working on anything.

I guess Ill see how long they stay on for....

And yes, I think I will drop a cable down from the projector to the show control computer. Question though... Currently the company that is renting the space is running the sound and projections from the Stage Managers Laptop (Not in QLab, I think its just a Quick Time movie maybe) using the HDMI cable. They are using the house Show Control computer (wirelessly) to shutter the projector when they curtain flies in. Can I have two laptops running the projector, or do I need to install my QLab file onto their computer, or their Quicktime movie onto mine?

@JVV I can't speak to your computer and video queries; I still suspect your intermittent program sound monitor issues may come down to corrosion on one, or more, connectors in your audio system's hard patch. @FMEng @Ancient Engineer @MNicolai and @TimMc Thoughts? Comments??
Toodleoo!
Ron Hebbard

 

[venuetech]

I would suspect dirty pots, especially if the system is over ten years old. It’s an easy fix, just exercise the pots involved in the system. You are trying to knock off a bit of corrosion within the pot, so wiggling it back and forth.

Very much like Ron suggests. Patch points can be unplugged and repluged with a twisting motion in an effort to get solid contact.

 

[RonHebbard]

I would suspect dirty pots, especially if the system is over ten years old. It’s an easy fix, just exercise the pots involved in the system. You are trying to knock off a bit of corrosion within the pot, so wiggling it back and forth.

Very much like Ron suggests. Patch points can be unplugged and re-plugged with a twisting motion in an effort to get solid contact.

@venuetech I believe the OP mentioned his audio hard patch utilized XLR connectors; I'll go with re-plugging and possibly De-Oxit but I'd avoid rotating.
Toodleoo!
Ron Hebbard

 

[Joshua Schoeneck]

Our auditorium has a multiple zone paging system and recently had a similar issue with one zone suddenly dropping out. After a lot of troubleshooting, we isolated it to a dirty pot on the mixer that splits the signal among the zones. There are potentially several pots in your signal path from mixer to amp to speakers that you might need to check and "exercise".

 

[Jay Ashworth]

This is the same cat that used his lapel-pin IR-LED and a little card to generate every display "off" command on the planet... at the NAB convention.
The look on the stick-figure doing the presentation at the Sony booth when all the screens went ...pffft... was pretty priceless, but seriously, this is a terrible maneuver too.

You can actually buy those as a retail device for about $50; they send "POWER OFF" in about 140 different IR codesets, baked into an acrylic housing that looks like a keychain flashlight; they're great fun at sports bars...

 

[Ben Stiegler]

In the booth there is an Amp labeled Front Lobby (which it seems also powers the Booth) and then Amps for Mains LR, (2) for Center Cluster, (2) for Subs and (2) for Stage Monitors which are the onstage wedges. There is an amp in the backstage rack (unlabeled) that supposedly powers the Booth and Dressing Rooms. The back of that amp has 2 channels outputs, one labeled LOB/B RM (which could either mean Lobby/Bathroom (since there are speakers in there) or Booth Room? The other cable is labeled TRM BLK OUT which I can't decipher. It also has a number (A1100) which, on the block drawing looks to go to the Light Control Room. These connections are all wire/screw and covered.

The hard patch in the back of the Sound Console are all XLR and we have unplugged and replugged the Backstage Send to make sure it is secure. But like I said, its being heard just fine in the booth. Even if the Booth is being fed from the Lobby as well (which it must be because when we turn the Lobby Amp off we loose the Booth). We also can hear in the Booth when the Lobby Send is off (not playing in the Lobby at least). And, when I disconnect the XLR for the Backstage Send, we loose the Booth.

Thanks for playing along. (Also, this morning the Show Control computer had switched wireless networks and was not talking to the projector and we lost the ability to mute which we discovered right at the top of the Dress Run. I almost cried, but didn't and figured out the issue.)

Terminal block output ... likely feeds a barrier strip from which a mighty fanout ensues...

As for intermittent sound ... if it’s not the pots, try wiggling any splices you can reach, as well as 3xposed csble loops that might have been stretched or pinched. I once maintained a hand built live audio quadraphonic mix console with a huge umbilical of analog in/out cables and the bundle proved sadly susceptible to damage which manifested if the 300# steel frame casterless console had to be moved for maintenance access to the backplane.

Pix! We love pix! Take some of your situation and post for us, please.