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Author Topic: LS9 nightmare  (Read 19603 times)

Ivan Feder

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LS9 nightmare
« on: March 03, 2011, 11:26:59 am »

Hi all,
thought I would share something that happened on an LS9  last night.
I was doing a corporate show (about 1000 pax). A couple of pairs on the board ( CD's, Beta, powerpoint) and about 10 mono inputs
Everything was fine for most of the day until I had to fade in a paired channel ( CD) as I started to push up one of the faders, the other one (paired one) went flying all the way up to max and the audio came at a horrendous volume!!!!
I quickly muted the channel but the monster was out  :-[
Needless to say that everyone in the room jumped and complained about the super loud sound that came out of the system (12 dV Doscs and 4 dV subs) and  production gave me a look like what the f#@%k have I done.
Now I could not use those channels anymore and I had to repatch the CD payer to other intputs.
I kept the pair muted and everytime I moved the left fader the right one would jump all the to maximum. I finally unlinked the pair and relinked it and the problem went away. Was not able to reproduce the problem after wards.
Anybody run into something like that?
The console is about 1 year old with latest firmware and was in use in normal conditions (temp. humidity, etc)
« Last Edit: March 03, 2011, 11:29:12 am by Ivan Feder »
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Tim McCulloch

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Re: LS9 nightmare
« Reply #1 on: March 03, 2011, 11:59:29 am »

I suspect there was an offset in fader levels when the channels were paired.  At the bottom of fader travel, a small difference in fader position can be 20dB or so, and almost impossible to see from the knob positioning.  That offset gets built into the link.

I've had the same thing happen on the M7, and when I looked at the numeric fader position in the Selected Channel view, I could see the difference.  Your action of unlinking the channels and re-linking them is the correct thing to do.  After I had this happen, I now only link channels after I've pulled them all the way down and confirm the "minus infinity" position for both channels on screen.

Have fun, good luck.

Tim Mc
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Jonathan Schroeder

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Re: LS9 nightmare
« Reply #2 on: March 03, 2011, 12:32:07 pm »

After I had this happen, I now only link channels after I've pulled them all the way down and confirm the "minus infinity" position for both channels on screen.

Have fun, good luck.

Tim Mc


I have gotten into the habit of pairing them when they are at 0, so any slight difference in position will not be a 20 db difference. 


You can also temporarily break the pairing on the M7 by holding the select key on a channel and moving the fader (or making any adjustments).  I also run one of the faders the full travel if I can to make sure they follow each other after initially setting up the link.  Usually, if I forget to link it before the show starts I leave them unlinked for the event.


Jon
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Geoff Doane

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Re: LS9 nightmare
« Reply #3 on: March 03, 2011, 12:37:18 pm »

I've had something similar happen on an LS9 when using paired channels, in this case the input gains for a stereo keyboard became offset, even though they had started off with the same gain.

I have to investigate it further, but I think what happened was that I recalled a scene in which the two channels were not linked, changed only one channel, and then recalled the original scene.  Fortunately, it was only the soundcheck, and I was probably the only one that noticed.

GTD
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Mac Kerr

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Re: LS9 nightmare
« Reply #4 on: March 03, 2011, 01:57:11 pm »

Everything was fine for most of the day until I had to fade in a paired channel ( CD) as I started to push up one of the faders, the other one (paired one) went flying all the way up to max and the audio came at a horrendous volume!!!!

As others have said, this was almost certainly due to the faders not being at the same level when they were linked. They will move in proportion to the offset, and when paired at or near -infinity the offset can be huge at the top of the fader travel. It is much safer to link the faders in the full up position instead. Linking them at "0" on the fader gives the best resolution, but it is harder to get them both the same.

Mac
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Ivan Feder

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Re: LS9 nightmare
« Reply #5 on: March 03, 2011, 02:48:10 pm »

As others have said, this was almost certainly due to the faders not being at the same level when they were linked. They will move in proportion to the offset, and when paired at or near -infinity the offset can be huge at the top of the fader travel. It is much safer to link the faders in the full up position instead. Linking them at "0" on the fader gives the best resolution, but it is harder to get them both the same.

Mac

What I didn't make clear in the description of the problem was that this pair had worked perfectly well for at least 10 hours prior to the incident.
I hadn't modified in any way the linking of the 2 channels.
This just suddenly happened!
(I would push up the left fader 1/16 of an  inch (starting at -infinity) and the right fader would jump all the way up (+10) in a split second.
I don't think the problem came from some " offset" since I had been using the pair many times that day.

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Mac Kerr

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Re: LS9 nightmare
« Reply #6 on: March 03, 2011, 03:22:56 pm »

What I didn't make clear in the description of the problem was that this pair had worked perfectly well for at least 10 hours prior to the incident.
I hadn't modified in any way the linking of the 2 channels.
This just suddenly happened!
(I would push up the left fader 1/16 of an  inch (starting at -infinity) and the right fader would jump all the way up (+10) in a split second.
I don't think the problem came from some " offset" since I had been using the pair many times that day.

Do you have more than one scene? Did anyone else have access during that time? Nothing is impossible in this world, but for the relationship between the 2 channels to change, it seems most likely that there was some other change made that caused it. That relationship might have been broken and remade in a scene change, or buy another user accidentally.

Mac

Mac
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Ivan Feder

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Re: LS9 nightmare
« Reply #7 on: March 03, 2011, 03:27:31 pm »

Do you have more than one scene? Did anyone else have access during that time? Nothing is impossible in this world, but for the relationship between the 2 channels to change, it seems most likely that there was some other change made that caused it. That relationship might have been broken and remade in a scene change, or buy another user accidentally.

Mac

Mac
Sorry Mac but none of those things happened.
I was the only user and I didn't even make any scene changes.
I know , it stumps me to!
Must be some kind of bug?
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Rob Spence

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Re: LS9 nightmare
« Reply #8 on: March 03, 2011, 03:33:57 pm »

I have also had this happen. In my case I have 2 pair always assigned to playback and sometimes after powering up the desk I find the flying fader showing up. Unlink-relink does fix it, but I also have been bit by the super loud problem.

I think I will take Mac's suggestion next time I power up the desk and re-link them at max instead of min.
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Mac Kerr

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Re: LS9 channel parameters
« Reply #9 on: March 03, 2011, 03:40:18 pm »

I have also had this happen. In my case I have 2 pair always assigned to playback and sometimes after powering up the desk I find the flying fader showing up. Unlink-relink does fix it, but I also have been bit by the super loud problem.

I think I will take Mac's suggestion next time I power up the desk and re-link them at max instead of min.

I am not too familiar with the LS9 (and I like it that way), does this fader link also link all the other channel parameters? If it is only a fader link I would avoid it altogether and just push up 2 faders. If it is the only way to link the other parameters like eq, dynamics, and routing, I guess you have to live with it since setting eq and dynamics for each channel separately would be a big PITA. I usually only link faders when they are on different layers. On a DM2000 you link each parameter individually, on a PM5D, all together.

Mac
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Re: LS9 channel parameters
« Reply #9 on: March 03, 2011, 03:40:18 pm »


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