Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[William Schnake]

Hi guys and gals.  This year we purchased several, 48 in total, LED Par lights.  We have up until now been hanging them individually and as you can imagine, it is time intensive.  I am going to make up Par Bars with 4 lights to a bar, using 40 of the lights.  This way everything is pre-wired and it will cut down on setup time as well as tear-down, it's all about the out.  I will leave 8 lights to be used without any mounting.  Anyway, here is my question:

The LED Pars are 18x18 watt with a zoom or 10 degrees to 60 degrees.  How much space on the bar should I leave between each light?  Our general hang is between 13' and 18' above the stage depending on where we are setting up.  Here is a link to the exact light we are using:

https://www.szbecen.com/product-item/18x18w-rgbwa-uv-6in1-led-waterproof-zoom-par-light/

As always, Thanks for your insight and help.

Bill

[Taylor Hall]

The short answer is that it will vary depending on how tall you place them. Given your height range that could change quite a bit.

I've learned that with most fixtures with a zoom function, the real world angle is often quite different than the spec sheet (especially for off-brand fixtures). I'd set up a couple aimed at a wall to test the actual dispersion pattern of light and go from there. You may be able to get a bit cheeky by massaging your gaps to let you adjust the zoom dependent on your height range and keep a pretty uniform coverage of everything and not have to shift your fixtures on the bars (ie tighter zoom at higher trims, vice versa at lower trims).

I would guess that one every 1.5-2 feet would be a good starting point given your height, let us know how they work.

[William Schnake]

I would guess that one every 1.5-2 feet would be a good starting point given your height, let us know how they work.

Taylor, very good points.  I am going to check the truss we have.  I marked where each light was and just now thinking about it I believe that we used a 1.5' distance from center of light to center of light.  I'll check.

Thanks

[Jeff Lelko]

Hi Bill, I think the first thing to consider is how these lights will be utilized.  Are they front/side/back fill, effects & eye candy, all of the above?  The second question I'd ask is how long of a Par Bar are you making? 

The catch with Par Bars is that in order for their size/weight to be manageable, you're more or less looking at a bar of 4-6ft up to 7.5 or 8ft - the latter if comparing to the 6ch Soca Bars.  In the 4-6ft range you'd be looking at 4 fixtures per bar as mentioned per your original post, and you might be able to squeeze 6 onto a 7.5 or 8 footer.  That said, the spacing between fixtures is more or less fixed due to the logistics of mounting them.  Unless you're shooting the tightest beam possible for eye candy effects the spacing between fixtures at that point is trivial since you have such little bar to work with.  I'd size for logistics unless you really think you might someday need 6 fixtures per bar (either for more output or more discrete units, hence my first two questions).  And yes, you could always mount fixtures both below and above your bar if you need higher numbers in tight spaces, but I'd wager that's beyond the scope of your question! 

I typically use 4 Par 64 sized fixtures or 6 Par 38 sized fixtures evenly spaced on a 5ft bar - the 5ft because it's an even cut of 10ft pipe and that it can ride width-wise in a utility van.  The 7.5ft Soca bars and similar usually need a truck or trailer if being moved pre-rigged.  Hope this helps!       

[William Schnake]

Hi Bill, I think the first thing to consider is how these lights will be utilized.  Are they front/side/back fill, effects & eye candy, all of the above?  The second question I'd ask is how long of a Par Bar are you making? 

The catch with Par Bars is that in order for their size/weight to be manageable, you're more or less looking at a bar of 4-6ft up to 7.5 or 8ft - the latter if comparing to the 6ch Soca Bars.  In the 4-6ft range you'd be looking at 4 fixtures per bar as mentioned per your original post, and you might be able to squeeze 6 onto a 7.5 or 8 footer.  That said, the spacing between fixtures is more or less fixed due to the logistics of mounting them.  Unless you're shooting the tightest beam possible for eye candy effects the spacing between fixtures at that point is trivial since you have such little bar to work with.  I'd size for logistics unless you really think you might someday need 6 fixtures per bar (either for more output or more discrete units, hence my first two questions).  And yes, you could always mount fixtures both below and above your bar if you need higher numbers in tight spaces, but I'd wager that's beyond the scope of your question! 

I typically use 4 Par 64 sized fixtures or 6 Par 38 sized fixtures evenly spaced on a 5ft bar - the 5ft because it's an even cut of 10ft pipe and that it can ride width-wise in a utility van.  The 7.5ft Soca bars and similar usually need a truck or trailer if being moved pre-rigged.  Hope this helps!     

Jeff, great questions.  Here is some clarification.

Front Truss 12' - 15' above stage level flown off of Genies.  These are mainly for a nice front wash.  We also attach a couple of movers on this truss and a couple of blinders.

Back Truss 13' above the stage flown off of my Global Truss stands.  This truss also has two movers, sometimes 4 movers.  Not being a lighting guy I say this is where the eye candy happens and the front truss is mainly a wash.

I believe that each light weighs in at 22 lbs.  I would like to mount them 4 to a bar to keep them manageable.  I was thinking 9 inches between lights.  From outside to outside each light is 12.75" in width.

I don't want to go 6 fixtures to a bar due to weight.

Hopefully this will help.

Thanks
Bill

[Jeff Lelko]

Okay, so for your front truss the spacing between fixtures is irrelevant so long as you're still hitting the right angles, so I'd base this decision on logistics alone.  The back truss has a bit more aesthetic precedence, but the spacing between fixtures still isn't as critical so long as you're able to get the number of units in place that you need to make the effects you're looking to create.  This is one of those situations where using a visualizer to preview the setup can't hurt, but if you don't have that available any basic graphics program will give you a ballpark idea of what things will look like from a fixture spacing standpoint.

I agree that from a weight standpoint that 4 fixtures per bar is probably best.  How does the length of each bar affect your loading plan?  Doing some basic math, you can squeeze onto a 5ft bar but not with 9 inches between fixtures - more like 3 if you don't want overhang on the ends.  The 9" spacing will fit on a 6ft bar.  Going to 7.5ft can get you around a foot in between fixtures which aesthetically might be a reasonable compromise (especially for your upstage truss), but anything longer than 7.5ft starts having loading considerations in most trucks since they can't be turned sideways at that point.  It all depends on how you want things to look, but at least for me, loading/packing logistics are just as important to consider as is the end product.  Good luck!     

[William Schnake]

I agree that from a weight standpoint that 4 fixtures per bar is probably best.  How does the length of each bar affect your loading plan?  Doing some basic math, you can squeeze onto a 5ft bar but not with 9 inches between fixtures - more like 3 if you don't want overhang on the ends.  The 9" spacing will fit on a 6ft bar.  Going to 7.5ft can get you around a foot in between fixtures which aesthetically might be a reasonable compromise (especially for your upstage truss), but anything longer than 7.5ft starts having loading considerations in most trucks since they can't be turned sideways at that point.  It all depends on how you want things to look, but at least for me, loading/packing logistics are just as important to consider as is the end product.  Good luck!     

Jeff, Thanks for the ideas.  I have a truck that is 92" wide on the inside.  I have come up with a 84" or 7' bar which will leave me enough room to turn the meat rack around in the truck.  I am going to have a meat rack built to handle 6 bars of lights. 

Here is what I have come up with for each bar of lights:

1.5" on the end
12.75 for light one
10" open
12.75 for light two
10" open
12.75 for light three
10" open
12.75 for light four
1.5 on the end

We should still have enough room to hang two movers on the front truss on the same line as the pars and then on the top bar of the truss we can hang our crowd blasters.

Thanks
Bill

The space from light center to light center will be 22.75", which is about 13" between the outside lens on a light to the outside lens of the next light.

[Jeff Lelko]

Awesome, I think that's a solid plan.  Let us know how it turns out!

[Don T. Williams]

Because my bars were hold-outs from my days of using pre-rigged truss and a 120 can PAR 64 "standard rig".  I chose the 15" center to center spacing that was used for the 6 light Socopex PRT bars.  I use only 4 LED "cans" per bar on a 58" bar to keep it from being too heavy.  My LED's are not as large or heavy as yours are.  My first bars were left over steel tubing from the 4-pack 28V ACL PAR bars I had made, but I found some 2" OD aluminum .063 wall tubing that saved more weight as a replacement for the steel tubing.

[Mark Cadwallader]

Because my bars were hold-outs from my days of using pre-rigged truss and a 120 can PAR 64 "standard rig".  I chose the 15" center to center spacing that was used for the 6 light Socopex PRT bars.  I use only 4 LED "cans" per bar on a 58" bar to keep it from being too heavy.  My LED's are not as large or heavy as yours are.  My first bars were left over steel tubing from the 4-pack 28V ACL PAR bars I had made, but I found some 2" OD aluminum .063 wall tubing that saved more weight as a replacement for the steel tubing.

If the .063" wall tubing works for you, that's cool. FWIW, Innote that even light-duty truss like Global is .080" (2 mm) wall thickness.  Standard truss is .125" (3 mm).  Because of the way aluminum fails (suddenly, compared to steel) you might want to inspect those bars more frequently to look for stress risers in the tubing.

[Joel T. Glaser]

Jeff, Thanks for the ideas.  I have a truck that is 92" wide on the inside.  I have come up with a 84" or 7' bar which will leave me enough room to turn the meat rack around in the truck.  I am going to have a meat rack built to handle 6 bars of lights. 
......

William, I'd love to see pictures/plans of whatever you end up with for your racks. Been thinking about building something for my light bars. Any input is much appreciated. - Joel

[William Schnake]

William, I'd love to see pictures/plans of whatever you end up with for your racks. Been thinking about building something for my light bars. Any input is much appreciated. - Joel

Joel, it will be a couple of months before we get this project done.  I will make sure that I post pics back to this post.

If the .063" wall tubing works for you, that's cool. FWIW, Innote that even light-duty truss like Global is .080" (2 mm) wall thickness.  Standard truss is .125" (3 mm).  Because of the way aluminum fails (suddenly, compared to steel) you might want to inspect those bars more frequently to look for stress risers in the tubing.

Mark, we will definitely be using aluminum.  I am thinking .125 due to the weight of the 4 lights to a bar.  Safety first.


Because my bars were hold-outs from my days of using pre-rigged truss and a 120 can PAR 64 "standard rig".  I chose the 15" center to center spacing that was used for the 6 light Socopex PRT bars.  I use only 4 LED "cans" per bar on a 58" bar to keep it from being too heavy.  My LED's are not as large or heavy as yours are.

Don, I use 15" on center for my 7 x 18 pars and that works great.  However, as you point out that is not enough room for the larger 18 x 18 lights that we use.

Thanks to all of their help.

Bill

[Don T. Williams]

If the .063" wall tubing works for you, that's cool. FWIW, Innote that even light-duty truss like Global is .080" (2 mm) wall thickness.  Standard truss is .125" (3 mm).  Because of the way aluminum fails (suddenly, compared to steel) you might want to inspect those bars more frequently to look for stress risers in the tubing.

Noted.  This could be a concern if this was structural in nature.   In my case, there are only four light-weight led "pars" (about 6 lbs ea.) attached to the bars.  The bars are clamped to my truss using two "double cheeseburger" clamps rated at 250Kg each with safety cables around the truss.  The "double cheeseburgers" are between the outer and inner pairs of "pars" - par-clamp-par-par-clamp par.  Pre wired and in sets of four it saves time and labor.  I would never consider using even a small "mover" or heavier light on this tubing.

[William Schnake]

I would never consider using even a small "mover" or heavier light on this tubing.

Don, good point.  We would only attach movers directly to the truss, never to a light bar.

Bill

[Mark Cadwallader]

Noted.  This could be a concern if this was structural in nature.   In my case, there are only four light-weight led "pars" (about 6 lbs ea.) attached to the bars.  The bars are clamped to my truss using two "double cheeseburger" clamps rated at 250Kg each with safety cables around the truss.  The "double cheeseburgers" are between the outer and inner pairs of "pars" - par-clamp-par-par-clamp par.  Pre wired and in sets of four it saves time and labor.  I would never consider using even a small "mover" or heavier light on this tubing.

Very good. You guys think about what you are doing before you do it.  My point was mostly for more casual (or new) folks who might be looking for a shortcut or a cheap "solution" without knowing all of the important caveats.

[ProSoundWeb Community]