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Creative & Custom LED Displays Engineering a 42sqm Concave COB Pro P1.25 Showroom Wall in Seoul
A Korean enterprise client needed a corporate showroom centerpiece in Seoul: a 42-square-meter concave COB LED wall wrapping across the room's focal wall. The catch — COB Pro cabinets are straight-edged aluminum die-castings, not flexible panels. To turn 208 flat cabinets into one smooth, deep concave arc, we engineered a custom curved floor-standing frame plus wedge-shaped arc connecting plates that set the exact pivot angle at every joint. The result: 15.6 meters of continuous, facet-free curve, driven by a single NovaStar H9 video wall splicer loaded with three H_20xRJ45 sending cards across 42 active Ethernet ports for 27 million pixels.
At a Glance
A Concave Centerpiece, Not a Flat Wall
The client didn't want another flat rectangle. They wanted the wall to curve inward around the room — an immersive concave canvas that pulls visitors into the content.
An enterprise client in Seoul reached out with a specific requirement for their corporate showroom: a 42.12-square-meter concave COB LED wall — 15.6 meters of arc length wrapping across the room's focal wall, rising 2.7 meters high. Content would be brand films, product visualizations, and data dashboards, all viewed by VIP visitors standing 1.5 to 2 meters away.
At that viewing distance, pixel pitch matters. P1.5 or P1.8 would show visible pixel structure. We specified COB Pro P1.25 — flip-chip COB with 10,000:1 contrast and a sealed 5H surface — so the image stays crisp and the screen survives cleaning and accidental touch in a high-traffic showroom.
The real problem, though, wasn't the pitch. It was the curve.
Straight Cabinets Don't Bend
A flexible LED panel bends natively — but it gives up the image quality. COB Pro delivers the image; the hard part is making its rigid aluminum cabinets follow a curve.
The COB Pro cabinet is a 600×337.5mm aluminum die-casting with perfectly straight edges — engineered for flat walls and front-service access, not for bending. Chained along a concave arc, 26 straight cabinets behave like a 26-segment polygon: every flat face must pivot outward at each joint to follow the curve.
Bolt those cabinets together with standard flat brackets and you get visible facets — angular breaks at every joint where the eye catches a corner instead of a curve. The deeper the arc, the worse it gets. The client's arc was deep, and "seamless, smooth transition" was a hard requirement written into the brief.
- Facet LinesAt 26 joints, even a fraction of a degree of misalignment becomes a visible seam line down the wall.
- Pixel Gap DriftAs cabinets angle away from each other, the pixel-to-pixel spacing across the joint grows — breaking image continuity at every seam.
- Flatness vs. CurvatureA concave wall has no single flat reference plane, so standard laser-leveling and flat brackets can't establish the geometry.
A Curved Frame & Wedge Connecting Plates
The solution had two parts: one to define the arc, and one to set the angle at every joint.
First, we designed a custom curved floor-standing frame. CNC-machined to the exact concave radius, it forms the single continuous reference line the cabinets mount onto. Because it stands on the floor rather than hanging from the wall, it absorbs the full 832 kg weight of 208 cabinets and gives installers a rigid, repeatable baseline to work from.
Second, we manufactured wedge-shaped arc connecting plates that sit between every pair of adjacent cabinets. Each plate is machined to the precise pivot angle for its position on the arc — so when two straight cabinets meet, the plate closes the gap and locks both faces onto the curve. The result is a continuous surface where the joints disappear into the arc instead of announcing themselves as flat segments.
Flexible SMD panels bend natively but trade away exactly what a corporate showroom needs up close: COB Pro's 10,000:1 contrast, flip-chip color uniformity, and sealed 5H surface. The frame-and-plate approach keeps every image-quality advantage of COB Pro while adding the curve — no compromise on either axis. Front-service access is also preserved, so any future module swap happens from the viewing side in minutes.
Arc connecting plates between each cabinet pair lock the pivot angle so 26 straight faces read as one continuous concave curve.
Driving 27 Million Pixels
The curve was the visible challenge. The quieter one was behind the wall: 42 square meters of P1.25 COB doesn't run on a standard LED sender.
At P1.25, a single square meter holds 640,000 pixels. Across 42.12 m² that's 26,956,800 pixels — a 12,480 × 2,160 canvas, roughly 3.25 times the resolution of 4K. That pixel count dictates the entire processing topology.
Two H_20xRJ45 sending cards top out at 26 million pixels — mathematically just short of the wall's 26.96M. So we loaded a single NovaStar H9 video wall splicer with three H_20xRJ45 LED 4K sending cards. Because all three cards live inside one chassis with a shared frame lock, content sweeping across the 15.6-meter arc stays perfectly synchronized with zero tearing at the card boundaries — no external sync card required.
Three cards running at 27M pixels sit at roughly 69% of their 39M combined capacity — comfortable margin, not a redline. That headroom absorbs peak content loads and leaves room to extend the wall later. The 18 spare Ethernet ports also mean a single failed port never takes a section of the arc offline mid-presentation.
Receiving cards are distributed across the 208 cabinets, with each active Ethernet port feeding a conservative count of cards — well within the recommended load, so no port risks frame drops even at peak content.
Project Specs
From Shenzhen to Seoul in Four Weeks
Arc Geometry & Design
Room dimensions and viewing distance captured. Concave radius and per-joint pivot angle calculated. Curved floor frame and wedge connecting plates designed.
Frame & Plates Machining
Custom curved frame and arc connecting plates CNC-machined in Shenzhen, while 208 COB Pro P1.25 cabinets run through standard production in parallel.
Pre-assembly & Aging
Full wall pre-assembled on the arc frame in-factory and run through 72-hour aging. Joints inspected for facet-free transitions before disassembly and packing.
Install & Commissioning
Frame installed in Seoul, cabinets mounted, NovaStar H9 with 3× H_20xRJ45 cards configured. Color calibration across the 15.6m arc with remote commissioning support.
Planning a curved LED wall?
Get a free arc geometry + processor topology design from our engineering team within 48 hours. Includes concave radius calculation, frame and connecting plate spec, and the exact processor count for your pixel load — specific to your room dimensions.
Frequently Asked Questions
How do you build a concave (inward-curving) LED wall from straight-edged cabinets?
Why use COB Pro instead of a flexible LED panel for a concave wall?
What viewing distance does P1.25 COB support?
What video processor does a 27-million-pixel COB wall need?
Can the concave curve use a different radius, or multiple curves?
What is the lead time for a custom concave COB showroom wall?
What certifications do DOIT VISION COB Pro displays carry?
Do you provide remote support for overseas installations like Seoul?
Products & Resources
COB Pro Series
P0.62–P1.875 fine pitch COB LED. Flip-chip, 10,000:1 contrast, 6 models, 16:9 600×337.5mm cabinet.
Explore →Fine Pitch LED Displays
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Explore →Corporate Showroom LED
Full-service showroom LED display solutions. Design, engineering, global installation.
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