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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => SR Forum Archives => LAB Lounge FUD Forum Archive => Topic started by: JohnRoss on April 19, 2010, 12:56:19 am

Title: Just wondering... VRX Question
Post by: JohnRoss on April 19, 2010, 12:56:19 am
Isn't this hung incorrectly? From what I've pieced together off here if the array cabinets aren't designed as separate left hand and right hand units they simply hang the same direction. The more I look at VRX lines for sale I see more of them hung upside down.
Title: Re: Just wondering... VRX Question
Post by: Tim McCulloch on April 19, 2010, 01:18:21 am
Other than the sound coming out upside down Wink  what I'm concerned with is the rigging.  While this load is fairly light, the truss should be loaded from the TOP chords, not the bottom.  Always bring the point into compression, not tension.  Hanging from the bottom chord puts tension on the lacing and it's welds as it tries to pull down.  Putting the load on the top chord distributes the load through the lacing to the bottom chord.

The asymmetrical layout of the 12" and HF waveguides makes for an interesting horizontal pattern.  Hanging them with one side inverted at least makes the horizontal coverage symmetrical.

Have fun, good luck.

Tim Mc.

ps.  got your PM, we'll take later.
Title: Re: Just wondering... VRX Question
Post by: Jayson Sladen on April 19, 2010, 01:45:43 pm
I'm not really sure how they've got the flybar on there, as the links are built into the boxes, and only allow you to go one way.  

Unless, of course, this user has obtained some additional links and pins?  Or made up their own flyware using box steel or unistrut and M12 bolts into the threads on the box?

Whilst on the subject, we were thinking about casting or otherwise making an alternative box to box link for 932's which would take some of that 15 degree per box curve out of a hang.  Instead of the straight piece that is currently attached to each side of the box, imagine a replacement angled piece either side.  You'd do the top 3 or 4 boxes of a hang of 6.

Question is, just how much would this bugger up the 'constant curve'?  I'm talking 2.5 degrees between each of the top 3 or 4 boxes, the the bottom 2 at the standard 15.  Clearly, the intent here is to enable more boxes to be used without ending up with the bottom box uselessly pointing at the floor.  Would it comb so much as to be unuseable?  If it worked, it'd turn a handy small format rig into something fantastic.  Has anybody tried this?

Title: Re: Just wondering... VRX Question
Post by: Rob Spence on April 19, 2010, 01:56:12 pm
Gee, if you change the curve it won't a constant curve array any more and might not work well. Also, how many boxes are the hardware rated to support?

These are not a classic line array as far as I know.

Also, if you change the hardware, then it isn't rated any more which can lead to liability issues should something happen.
Title: Re: Just wondering... VRX Question
Post by: TJ (Tom) Cornish on April 19, 2010, 02:05:46 pm
Maybe the folks in the picture used the flybar in groundstack mode?  Not sure, but might be a possiblity.  

I own the competing product - the EAW JFL210 stuff.  EAW claims that the VRX don't have flat wavefront characteristics, which means they won't sum very well if you change the splay.  EAW claims that the JFL does have more of a flat wavefront and if you figured out some way to re-rig to straighten the curve it would work to some degree.  I don't plan on trying this.

It seems to me that this is working pretty hard to get either of these boxes to do something they weren't designed for.  A Vertec 4886 system would be more appropriate, though a lot more money, if that was important.