Why Using the Very Best That Cree Has to Offer — Matters

By Dr Dominik Ostrowski, MIET — Founder and embedded-systems engineer, Think Radio

It would be easy to assume the LED itself is the whole story. It isn't. Z-RAY uses the best LEDs Cree has to offer — but the chip is only the raw material. What actually determines whether a light looks good, stays consistent across a rig, and survives years of touring is everything built around that chip: the driver circuit, the thermal management, the binning discipline, and the dimming engine behind it. Get those wrong and even an excellent LED looks mediocre. Get them right, and the difference shows up in ways a spec sheet never captures — but a camera may.

This is the "why" behind the parts list: not just that Think Radio paid for good components, but knowing exactly why only good components will do, and how to get the most out of them.

The part everyone can see: smooth fades, not visible steps

The most immediately visible difference between a cheap fixture and a well-engineered one shows up the moment you run a slow fade — a sunset cue, a gentle pulse, anything that asks an LED to move smoothly through brightness levels rather than snap between them.

Most lighting fixtures dim using PWM (pulse-width modulation) — switching the LED on and off fast enough that the eye perceives a steady brightness rather than a flicker, with the proportion of on-time versus off-time setting the apparent brightness. The resolution of that control matters enormously. A common, cheaper approach gives you only 8-bit PWM — 256 discrete brightness steps from off to full. That sounds like plenty until you try a slow sine-wave fade at the low end of the brightness range, where each of those 256 steps represents a comparatively large jump in actual output. The result is visible banding — a fade that should look continuous instead stutters in small, visible steps, especially in the darker part of the curve where the eye is most sensitive to contrast.

Z-RAY's driver is built around Nordic Semiconductor's PWM engine, which offers four channels each with 32,768 steps rather than 256 (i.e. each colour uses 2 DMX channels, rather than 1, giving coarse and fine adjustment). That's not a marginal improvement; it's the difference between a fade the eye reads as a single smooth motion and one it reads as a sequence of visible jumps. It's a deliberate choice at the driver level, not a property of the LED chip itself — which is exactly the point of this piece.

Z-RAY can do both 8-bit and 16-bit DMX modes on all of the Red, Green, Blue and White LEDs. 8-bit is literally what every bit of lighting control software and/or hardware can do anywhere - it's universally-compatible. 16-bit mode is rather more high-end. If your set-up supports it - and especially if you use slow-fades - then use it. If your current rig doesn't support 16-bit - you still know that your Z-RAYs do - and you can move up to 16-bit at any time in the future (in fact - internally - Z-RAY always operates in the high-precision mode).

Many products may describe inputs as 16-bit, but how do you know how many of those bits get discarded? Generally manufacturers don't tell you, but Think Radio does. Z-RAY discards the least-significant bit only - and that's a level of precision no human eye could tell apart.

The part a spec sheet doesn't capture: how it holds up on camera

The second driver-level decision matters even more for anyone recording or filming a show, which — on an increasingly video-first touring and event circuit — is close to everyone.

PWM dimming works by switching the LED on and off at a fixed frequency, invisible to the naked eye. But a camera doesn't see light the way an eye does — it samples light in discrete frames, at a shutter speed set by the camera, not the fixture. When a fixture's PWM frequency isn't high enough relative to the camera's frame rate and shutter speed, the two start to beat against each other, and the result is visible flicker, banding, or rolling dark bars across the footage — a problem anyone who has filmed under cheap LED lighting has probably seen, usually without knowing why it happened or that it was avoidable.

Z-RAY's driver runs its PWM refresh at a high enough frequency that this interference doesn't occur — the light reads as clean and stable on camera across the range of shutter speeds a touring videographer or venue is actually likely to use. This is a concrete, demonstrable difference: point a phone camera at a cheap fixture doing a fade next to a Z-RAY doing the same fade, and the difference is immediately visible on screen, not just in a spec comparison.

For top video performance, switch off any cheaper low-refresh-rate lighting - DMX, fixed venue lighting etc. Video-friendliness is one of the real tests of quality.

What goes wrong with cheap or mismatched LEDs

LEDs look so simple, and in fact they are simple compared to older lighting technology. A few volts, a modest amount of current, and Bob's your uncle. And for trivial uses as indicators that is entirely true.

When using higher-power LEDs for lighting purposes it gets a bit more complicated. Each colour (red, green, blue, white) has a different voltage threshold, and it's going to take something a bit more sophisticated than a resistor to control the current - because the light output is proportional to current, not voltage. The modern solution is constant current sources, that are suitable both to the very rapid switching required by PWM, and operate independently of temperature-related changes that power LEDs are prone to.

In fact really good thermal management of power LEDs makes all the difference. There's basically 2 choices, active or passive. Active means fans, which in turn means battery-drain and fan-noise. Passive means physical metalwork. Fortunately LED efficiency has improved greatly, as has the cost of solid-aluminium PCB technology. And that's how Z-RAY does it. Passive heat-sinking, a large aluminium PCB, and a design that even after an extended gig will only be gently warm to the touch.

Notice also that Z-RAY uses a single LED. It's cheaper to use multiple mono-colour and low power LEDs, and that's what you commonly see - a panel of individual red, green, blue (and possibly other colour) LEDs, all attached to a standard fibreglass PCB - with virtually no passive cooling ability.

But switch to a high-end LED like the Cree XLamp XM-L Color (Gen 2), pay (quite a bit!) more for a high-quality component, and you buy an exactly colour-matched, highly-efficient LED - that will easily out-perform individual-colour LEDs.

The real world

None of this is a claim that Think Radio designed a better LED chip — Cree did that, and did it well. The claim is narrower and more honest: that getting the most out of a genuinely good LED takes real engineering at the driver level — enough PWM resolution that a fade looks like a fade and not a staircase, enough refresh rate that a camera doesn't fight the fixture, and enough thermal and binning discipline that one Z-RAY matches the next. Buying the right chip is the easy part. Everything in this piece is about the part that isn't.