Building a DIY video wall

[EdK]

Hello everyone,

Complete novice here with no experience doing this sort of thing.

 

Looking to build a 3X3 (or larger...keeping a 16:9 aspect ratio or close to it) DIY video wall for a small theatre company on a minimal budget. Over 90% of the content being displayed would be Powerpoint presentation with occasional short video clips. The theatre company currently rents a venue that does this but they will be building their own venue.

 

The purpose of the video wall is to project background scenes as an alternative to building sets, etc. The images being displayed would need to be split among all of the TVs/monitors to create one large image. This is the way it's currently being done at the venue they are renting.

 

The control booth would be on the opposite side of the space approximately 100 feet away.

 

Most DIY projects that I've been able to find by perusing the web have the 'control' PC close the the TVs/monitors using a video card with multiple HDMI outputs with an HDMI cable going from the PC to each TV/monitor. Running multiple HDMI cables to each monitor 100 feet away seems silly and impractical considering there would probably be significant signal loss over such a distance. Other projects that I've found have a single HDMI cable from the 'control' PC into a Cat6 cable then into one TV/monitor and then daisy chain the remaining TVs/monitors and somehow the TVs/monitors take care of splitting the images.

 

Does anyone have any suggestions on how best to accomplish this on a budget (both hardware and software) or where I could find information? Would prefer to stay away from 'projection' type solutions and they don't need 4k quality. Just something decent. Audience would be located a minimum of 20 feet away from the video wall.

 

Thanks! EdK

 

 

 

 

[mac.calder]

If you get a video wall display (all the big names do them) - they generally have the ability to loop through the input signal and then choose which section to display - ie you tell it that the wall is 3x3 and that it is monitor #2, it then shows the top centre ninth of the display.

 

That said - LCD monitors are not robust - in fact they are quite fragile. To make it look good you also need the appropriate hanging brackets with multi-axis adjustment and a rigid wall. Generally video walls are not great for theatre. And doing them in a way that looks good will cost far more than a projector.

[david.elsbury]

Many video walls (our current Samsung product in rental stock included...) have a gloss finish - remember they are just TVs with glass on the front; just a narrow bezel.

 

Glass means reflections; and since theatre has lots of lights.... it may not be the best solution.

 

What budget are you working towards?

[Jivemaster]

Video, cheap, good. Pick any two.

[sunray]

That said - LCD monitors are not robust - in fact they are quite fragile. To make it look good you also need the appropriate hanging brackets with multi-axis adjustment and a rigid wall. Generally video walls are not great for theatre.

To be quite frank I have found proffessional brackets are quite often a PITA for this sort of thing, we did one using 6x3 of 42" and the brackets spec'd by the consultant stayed in their sealed white and black paper sack packaging and returnded (in fact consultant cocked up the whole job). Instead we made a frame with 6m horizontal unistruts on floor to ceiling verticals and screwed straight through into the vesa points, then the demontable partition was rebuilt double thick under it.

And doing them in a way that looks good will cost far more than a projector.

Oh yes, the mounting hardware is often more expensive than the screens. Edited August 7, 2019 by sunray

[gyro_gearloose]

The OP might be better off looking at some of the ultra short throw projectors on offer these days. I'm assuming that the idea of a video wall was decided on so that the actors don't cast shadows on a projection screen? Using a short throw projector will help with this as the throw distance can be surprisingly short. One Dell projector I've seen claims to be able to create a 100" image with the projector a mere 4" from the screen.

[sandall]

The OP might be better off looking at some of the ultra short throw projectors on offer these days.

Ultra short throw projection can be great, but you need a really, really, flat & smooth surface (forget roller screens) if you don't want to see blemishes. I've only used them in low-expectation situations, but I suspect that definition at the top could be a bit iffy, especially with cheaper models.

[sunray]

The OP might be better off looking at some of the ultra short throw projectors on offer these days. I'm assuming that the idea of a video wall was decided on so that the actors don't cast shadows on a projection screen? Using a short throw projector will help with this as the throw distance can be surprisingly short. One Dell projector I've seen claims to be able to create a 100" image with the projector a mere 4" from the screen.

 

I suggest using ultra short projection with caution as everything about them is very critical.

The shortest I've done is 800mmfor a 72" drop down screen so not too extreme compared with whats out there, despite the warnings the customer insisted that was what they wanted installed. the uneven cloth almost looked like it was casting shadows on itself at the edges and the slightest air movement was like an earthquake.

Even solid screens need to be perfectly flat to avoid distracting distortions.

Having made these comments, I will say that a 1:1 on a fixed screen can give some very useable results and the risk of people casting shadows isn't too bad if the top of the screen is 2.4m or more high.

 

Edit: I started writing before Sandall made his excellent post.

[alistermorton]

We use a fairly short throw projector (4 m ish) projecting down from the stage grid (about 4m ish too, I'd guess) and you can get surprisingly close to the cyc before shadows from cast members become a problem.

[sunray]

We use a fairly short throw projector (4 m ish) projecting down from the stage grid (about 4m ish too, I'd guess) and you can get surprisingly close to the cyc before shadows from cast members become a problem.

I was trying to say the same thing.Assuming a 1:1 projection and the bottom of the image is at floor level, the light comes down at about 45^o. A 6ft person can get to 6ft of the screen before casting a shadow.

I know it's counter intuitive but I've found mounting the projector low down (in a bit of the set?) can sometimes create less shadow trouble.

 

[sandall]

The big problem with projection behind the action is the image being washed out by light from FoH bouncing off the stage (lighting faces is easy - sorting out where the light goes afterwards is the clever bit). This means using more 2-point & side lighting, & rules out any low-angle stuff coming straight in from FoH.

 

Alistair's hanging solution is a good one, but if you have the space behind the screen then back-projection wins hands-down (& also removes the no-go zone near the screen).

 

Even solid screens need to be perfectly flat to avoid distracting distortions

A local church got talked into buying one of the ultra short throw things (at 3x the list price, because it came in a box with a speaker!!) to project onto the plastered wall behind the altar - it looks horrible!

[alistermorton]

True, whenever we're using projection the lighting design upstage has to be different to avoid lighting the cyc, but we're used to it, and it works really well for us. Our recent productions of Daisy and Pitmen Painters used a lot of projection and washout was never a problem.

 

Pitmen image:

 

http://www.millercentretheatre.org/images/201819/ThePitmenPainters/IMG_9963.jpg

 

 

 

The window image was far brighter to the eye than the camera has picked up here.

Edited August 9, 2019 by alistermorton

[sandall]

That's pretty impressive... Presumably the projection goes right down to the floor?

[alistermorton]

Yes, covers the whole visible area.

 

In an earlier scene, where Oliver Kilbourn and the other painters met Lady Sutherland at the hall, the scene started in the gardens, with the flowers in the foreground and the stately hall in the distance. The projection then zoomed towards the hall, then the window and the scene then turned "inside out" and we were transported inside the hall. All done in qlab. The fellow who put the projections together really got to know qlab well and did a fantastic job.

Edited August 9, 2019 by alistermorton

[sandall]

Even more impressed :)