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Author Topic: line array issues.  (Read 1592 times)

Ray Soly

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line array issues.
« on: April 27, 2019, 02:58:32 pm »

Line array specialists :

One of the venues I regularly play in has discovered recent or not so recent issues with their Main M1D rigs used as orchestra support for ballet /operas..

Right side was found to have 5 boxes out of the 11 with defective/dead tweeters, I don't know where these are located in the hang, Left side was ok!...these boxes feature 3 x tweeters per box along with 2 x 5" woofers crossovers are at 1900 hz....obviously the system didn't sound as pristine as it once did and is scheduled for replacement with a meyer CAL ...but my question is, would it not have been quite evident that that side of the PA was missing highs? regardless of where the missing tweeters were located ?  or would it just be a few dbs low over the high spectrum (less than -3db as it still had its tweeters in the other 6 boxes??)  or. ??? what if they were the top 5 in the array, wouldn't that be evident on the orchestra level for ex.?

And what could cause this ? again I don't know which processor output was driving which set of M1Ds ...

All I was told was that the 2 sides sounded different enough  (nothing drastic though) to warrant further investigation, and that eventually each box  (they're all on separate breakers ) was sent signal and compared to a known good box.....

The bad ones were sent out for repair and replaced with spares they had on hand.....

Thanks

Ray
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Roland Clarke

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Re: line array issues.
« Reply #1 on: April 27, 2019, 04:03:27 pm »

Should be easily audible, however, depending on listening location and material, perhaps not as obvious as you might think.  Pink noise is great for checking things, makes a lot really obvious.
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Keith Broughton

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Re: line array issues.
« Reply #2 on: April 27, 2019, 04:14:25 pm »

I would say that, with line arrays,  so many arrivals from different sources can make it  hard to locate the problem driver(s) by listening in the house.
Testing each box, individually, is the best way.
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David Morison

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Re: line array issues.
« Reply #3 on: April 28, 2019, 06:29:30 am »

Line array specialists :

One of the venues I regularly play in has discovered recent or not so recent issues with their Main M1D rigs used as orchestra support for ballet /operas..

Right side was found to have 5 boxes out of the 11 with defective/dead tweeters, I don't know where these are located in the hang, Left side was ok!...these boxes feature 3 x tweeters per box along with 2 x 5" woofers

You didn't specify whether it was all of the tweeters in the affected boxes that were out, or just some - so it could have been as few as 5/33 tweeters out, not 5/11. That would have made a big difference to the audibility of the problem.
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Ray Soly

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Re: line array issues.
« Reply #4 on: April 28, 2019, 12:01:04 pm »

You didn't specify whether it was all of the tweeters in the affected boxes that were out, or just some - so it could have been as few as 5/33 tweeters out, not 5/11. That would have made a big difference to the audibility of the problem.

Alas I don't have this info, no one opened the boxes and I was not told if the defective boxes had no highs at all or just sounded different enough from the known good box to warrant replacement......

Ray
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Jean-Pierre Coetzee

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Re: line array issues.
« Reply #5 on: May 04, 2019, 03:20:59 am »

How long has that rig been installed? The M1D is a rather old box so if it's been installed for 10+ years some damaged components isn't an impossible thing to consider.

Blown HF driver would usually be some sort of transient as far as I can tell, not muting something before unplugging, not killing speakers before killing the console, stuff like that. Not saying its intentional nor that it is a common thing but across a long time span it's likely to happen once or twice especially if there a consistent crew working on it.

Also for those that don't know the three tweeters are 0.75" dome tweeters, used outside of their design characteristics I can imagine that would easily get abused.
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Re: line array issues.
« Reply #5 on: May 04, 2019, 03:20:59 am »


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