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Author Topic: Line Array Wiring  (Read 12713 times)

Brayden Cohen

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Line Array Wiring
« on: March 10, 2014, 11:15:52 PM »

I am a novice audio guy and am wondering, for my own insatiable crave for knowledge in live sound, How do companies and guys wire up a line array to the amps especially when they are tri-amping?

(example) 6 JBL vertecs 4889 and 2 JBL Vertec 4880A and how do they choose amps for the rack?

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Brian Jojade

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Re: Line Array Wiring
« Reply #1 on: March 11, 2014, 01:03:57 AM »

With lots of speaker cables.  Amps are decided based on brands preferred, and power ratings of the speakers and the consideration of safety against blowing speakers vs squeezing the max out of the system.
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Tim McCulloch

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Re: Line Array Wiring
« Reply #2 on: March 11, 2014, 02:13:55 AM »

I am a novice audio guy and am wondering, for my own insatiable crave for knowledge in live sound, How do companies and guys wire up a line array to the amps especially when they are tri-amping?

(example) 6 JBL vertecs 4889 and 2 JBL Vertec 4880A and how do they choose amps for the rack?

I manage a VerTec shop. /disclaimer

The smart folks buy ITech HDs because that's how you get VerTec V5 presets.  If you're willing to do v4.2 you can use the original ITechs.

I could write up this big, long explanation but I think it's easier to send you to here:  http://hiqnet.harmanpro.com/tutorials/performance_manager/

Performance Manager is a subset of Harman's Audio Architect that has been designed specifically to address physical design, circuiting, amplification, signal routing, testing and operation of VerTec and Venue Precision loudspeaker systems.  While this may seem off on a tangent, your questions will be answered by watching the tutes.

Our shop adopted racking and powering from Schubert Systems in LA, putting 4 IT6000 or IT8000 in each rack.  We can power up to 8 4889 on 2 circuits, per rack.  Most commonly I put 3 4889 per circuit, so a hang of 12 speakers takes 2 amp racks.  If you watch the Performance Manager tutorials they use the Crown VRack, which has 3 amps per rack, but since they use the ITech HD, the 4x3500 comes into play.

For wiring, we use 8 conductor 12 ga and 14 cond 12 ga cable intended for lighting.  We have this split out, 8 conductors to NL8, 4 conductors to NL4, 2 conductors not used.  We use this cable for the top of the hang if we fly subs at the top of the array.  We have them in 125' and 75' put ups.
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Rory Maguire

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Re: Line Array Wiring
« Reply #3 on: March 11, 2014, 04:07:07 AM »

Or you could look into the L'Acoustic's standard method of wiring where you have 3 LA8 amps per rack (LA-RAK). Each amp can drive either 4 circuits of subs (With each circuit containing a pair of subs.) or two circuits of Mid-High cabinets. (With each circuit containing 3 Mid-High Boxes.)

The connections from the amp racks to the speakers are L'Acoustics CA-COM connector which uses their DO- cables.

So in an example of a rig with everything flown, four subs over 12 Mid High boxes, you could fly one of their LA-RAK, then run 3 short DO-10 (10m multi conductor speaker cable) into a DO-SUB (Subs) or DO-FILL (Mid-High) break out, and from there link to each speaker. (Three per circuit for the Mid-Highs, or a single sub in this example.)

In my head I'm putting together a small SB18 over KARA rig here...


Or you could use Meyer where you run a 12/16 way XLR multi and drive each box with it's own feed from a Galileo processor. The joys of a self powered box!
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Robert Weston

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Re: Line Array Wiring
« Reply #4 on: March 11, 2014, 08:37:02 AM »

I am a novice audio guy and am wondering, for my own insatiable crave for knowledge in live sound, How do companies and guys wire up a line array to the amps especially when they are tri-amping?

(example) 6 JBL vertecs 4889 and 2 JBL Vertec 4880A and how do they choose amps for the rack?

In my very limited experience from several years ago (and a high-level view...)

Line array cabinets (depending on brand/model/etc...) are either bi-amp or tri-amp only.  Some cabinets have 16ohm drivers for mids and highs; some have 8ohm drivers more mids and highs.

Multiple amps (or amplifier channels) are used to drive each individual speaker cabinet (or group of cabinets) in the array for mids, and highs.  The lows (subs) are sometimes in the arrays, but many times are on the ground; these can be wired probably like what you are currently doing.  The individual cabinets (mids/highs) are usually wired to allow for parallel speaker connections to adjoining cabinets. 

For example - assuming you are using amplifiers in 2-channel (stereo mode)... an NL4 speaker cable (2/pair wire) can be used to chain 4 x bi-amp cabinets together.  One pair of the NL4 would drive all the mids, the other wire pair would drive all the highs (for a 2 ohm load using 8 ohm drivers).  However, 8 x bi-amp cabinets could be connected together, but only if using 16 ohm drivers.

The amplifiers can be configured to run in 2 channel or bridged mode (whichever is needed to get the most power safely).  If the amplifiers used in the above example are in bridged mode, divide the total number of attached cabinets by 2 for the 8 ohm and 16 ohm examples.

Hopefully this wasn't too remedial.  Sometimes it's just easier to actually see how a rig is wired than to explain it in writing.










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Brayden Cohen

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Re: Line Array Wiring
« Reply #5 on: March 11, 2014, 11:22:06 PM »

@ Brian yea i know the cabling is crazy with racks and distro's and stuff. Now as far as blowing the speakers vs maximizing the sound i guess thats where DSP's like BBS Omnidrives and Lake processors come into play right?

@Tim Thanks for links very useful!! Now in regards to the 4889 do you tri amp? if so do daisy chain ya HF and MF signals?(if that makes sense)

@Robert Thanks for the info you help shed light on my question to Brian!
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Ray Aberle

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Re: Line Array Wiring
« Reply #6 on: March 11, 2014, 11:31:23 PM »

@ Brian yea i know the cabling is crazy with racks and distro's and stuff. Now as far as blowing the speakers vs maximizing the sound i guess thats where DSP's like BBS Omnidrives and Lake processors come into play right?

@Tim Thanks for links very useful!! Now in regards to the 4889 do you tri amp? if so do daisy chain ya HF and MF signals?(if that makes sense)

@Robert Thanks for the info you help shed light on my question to Brian!
Brayden,

The VerTec systems have multiple boxes per NL8 run; you jump from one box to another, and the amps feeding each conductor line of the NL8 handle certain parts of the boxes, the HF, MF, etc.

For VerTec and Crown I-Techs, check out:
http://www.crownaudio.com/media/pdf/amps/137327.pdf

This is Crown and JBL giving you a great place to start on wiring their systems together.

I built my VT4888 racks based on the suggestions. Since I started with 4-88s per side, I built two racks with two each IT-4000s and IT-6000s. When I get to six boxes per side, I will change out to 2-IT5000HD and 2-9000HD in each rack, which will then handle up to 6 boxes per rack.

-Ray
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Kelcema Audio
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Brayden Cohen

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Re: Line Array Wiring
« Reply #7 on: March 11, 2014, 11:45:52 PM »

@ Ray thanks for this diagram I appreciate it!!!

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Ray Aberle

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Re: Line Array Wiring
« Reply #8 on: March 12, 2014, 12:00:26 AM »

@ Ray thanks for this diagram I appreciate it!!!
No worries! Where do you live? You could probably find a LAB member near you that would love an extra hand on a big gig, and you could do a walk on, coil cables, push cases, and learn big rigs. That's what I did when I was ready to start learning about VerTec!

Are you planning to get on this level of production, or you just want to learn about it?

Ray
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Kelcema Audio
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Tim McCulloch

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Re: Line Array Wiring
« Reply #9 on: March 12, 2014, 12:22:48 PM »

@ Brian yea i know the cabling is crazy with racks and distro's and stuff. Now as far as blowing the speakers vs maximizing the sound i guess thats where DSP's like BBS Omnidrives and Lake processors come into play right?

@Tim Thanks for links very useful!! Now in regards to the 4889 do you tri amp? if so do daisy chain ya HF and MF signals?(if that makes sense)

@Robert Thanks for the info you help shed light on my question to Brian!
The most effective speaker protection is the relationship between the system engineer and the band's mixerperson.  Next is limiting built into the amp's processing, and finally external process units.

The current version of VerTec processing (v5) only exists for Crown's I-Tech HD series amplifiers while v4.x is available for original I-Tech and Lake, BSS and dbx processors.

VerTec 4889 and 4888 are tri-amp only and cannot be run any other way.  The 4887/4887a are 3 way speakers that operate bi-amped (the MF/HF crossover is passive, internal to the speaker).  The 4886 is a 3 way passive box.
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"If you're passing on your way, from Palm Springs to L.A., Give a wave to good ol' Dave, Say hello to progress and goodbye to the Moonlight Motor Inn." - Steve Spurgin, Moonlight Motor Inn

ProSoundWeb Community

Re: Line Array Wiring
« Reply #9 on: March 12, 2014, 12:22:48 PM »


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