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HDMI Copper vs. Fiber: The Need for Speed with 4K Video

If You Want the Best 4K Experience for Your Client’s Home Theater or Gaming System, Then Fiber is the Way to Go for Very Good Technical Reasons

I have exciting news to share about a new line of HDMI fiber optic cables called FIBBR (pronounced “fiber”). It hit all my checkboxes in this category: certified by ISF (thus far the only brand in the category worthy of that prestigious honor); the Best of CEDIA 2017 award from AVSForum (well known for their rigorous performance tests), and, most importantly, high reliability in the field at spec. The most noticeable thing about the HDMI cable category is that at least half of the brands fail to meet the speed spec of 18 Gbps; you have to do your due diligence before you buy any 4K HDMI cable, copper or fiber.

My company, Essence For Hi Res Audio, is now selling FIBBR’s Ultra Pro Series, and I’m happy to share my thoughts on the subject. This is an old debate: copper versus fiber, which is better and why? How far is too far on copper? Is fiber worth the extra money? Ten years ago I pioneered the PureLink HDMI fiber optic extenders for uncompressed 1080p at distances up to a mile. In large-scale 1080p deployments, from digital signage on the Vegas strip and Times Square, to command and control centers and broadcast networks, fiber optic was and continues to be the standard “best practice” for those long runs.

2017 will be remembered for, among other things, the emergence of 4K + HDR/Dolby Vision with WCG (Wide Color Gamut) video and native 24/96K Hi Res Audio soundtracks. Today’s data-rich content has increased dramatically, reducing the distance these signals can travel over copper by 50 percent. My post today is about whether using a copper HDMI cable of any length still makes sense or if it’s finally time to adopt HDMI fiber optics for all 4K sources and displays regardless of the length.

The price for fiber optics has come down, so it’s an option to consider when your client is buying r new 4K TV. If you want the best 4K experience for your client’s home theater or gaming system, fiber is the way to go for very good technical reasons: 18 Gbps is fast, but the speed of light is way faster.

In the previous generation of high-def video, the highest resolution was native 1080p from a Blu-ray disc. When we tested HDMI copper cables using the benchmark eye pattern test, we discovered that HDMI over copper at 1080p collapsed the eye at 33 feet, resulting in a black screen. For distances above 30 feet for 1080p, fiber optic connections became the standard for the best performance. Distances under 33 feet can use copper and get decent results on 1080p. With three times more data, native 4K is much more challenging than 1080p. HDMI v2.0a requires a new eco-system of sources, cables, DAC, and display for the new resolution to come through. Old HDMI cables will not work for 4K because they’re too slow. HDMI v1.4 inputs and outputs on your AVR or pre pro won’t either for 4K.

HDMI copper cables are rated for their impedance. The least expensive versions are 27 ohms, the medium-priced versions are 24 ohms, and the most expensive high-speed copper cables are rated for 21 ohms and sell for the highest prices. Cat-6 is rated at 23 ohms, so it’s no panacea. Impedance is a measurement of “resistance” or how much the signal is impeded from reaching its destination intact. Anybody with an earlier generation projector or display found out through trial and error long ago that fiber was required for long distance transmission of native 1080p signals.

The question we have to ask is, how much data is lost from this resistance at shorter distances and how does it affect the viewing experience? In other words, when did the degradation begin to set in? The answer will surprise you. Using un-compressed native 1080p signals at 10 feet, 15 percent of the data is lost through attenuation. At 20 feet, 50 percent is lost. By 33 feet, it’s all lost; the picture appears on screen but it’s not a one-to-one copy of the original signal. Overall brightness and contrast do not match the original.

Comparison Test

In our blind AB tests comparing a five-foot 4K HDMI copper cable (on the right) versus a five-foot 4K HDMI fiber optic cable, 10 out of every 10 consumers chose the fiber optic as the superior picture. Fiber delivers better color depth, brightness, and contrast, a more faithful copy of the original signal. You can see in the pic above that the screen on the left is delivering the actual content whereas the image on the right is washed out and missing the tail of light at the bottom completely. This is the result of data loss, even though the picture is there, its not accurate.

Copper is prone to electromagnetic interference (EMI). Stray EMI in our homes is rampant from all our wireless devices and copper cables pick it up like an antenna. This interference is seen as noise in the picture, a grainy effect that’s not present in the original content. When you see a side-by-side comparison of copper versus fiber at as little as five feet of distance, the effects of resistance and noise are clearly distinguishable. If you’re fussy about things like this like I am, you want to get it right.

At 16-20 feet on today’s highest speed-rated 4K HDMI copper cable the native 4K picture fails completely; it shows 50 percent attenuation and grain at eight to 10 feet, and 25-percent attenuation and grain at five feet. The old myth that copper is OK for HDMI as long as it’s a short run is no longer true. It may have been true in the last-generation 1080p era but not now. You get a “less-than-optimal” picture at even short distance on copper—not a true one to one copy of the original.

Some manufacturers use active HDMI copper cables, adding in an amplifier that boosts the degraded signal so it can travel a longer distance. Beware of these, as they add distance without improving the picture and run out of gas themselves, usually within 100 feet.

So lets look at the eye pattern tests because they reveal a lot. The rule of thumb is that if there’s no eye, then there’s no picture. The top panel is comprised of well-known name brand high-quality 4K, 18 Gbps copper HDMI cables at various short-to-moderate distances. They all fail above 20 feet. You see even at short distances, the eye is compressed—reduced in size; that’s what lost data looks like. You can see the 10-foot cable is almost out of gas, the 6.6-foot cable’s image is half gone, and at distances beyond 20 feet, it’s hopeless:

And now lets look at Ultra Pro HDMI v2.0b Fiber Optic Series by FIBBR in similar tests:

Fiber optics have zero resistance because they use light waves over glass fibers to transmit the audio and video signals at the speed of light. The result is zero signal loss and a clean, wide eye pattern at all distances. If bandwidth and data speed are the issue, then fiber wins hands down; nothing’s faster than the speed of light. Fiber optics are immune to EMI, so the picture is ultra smooth. Native 4K movies always look their best, and the added clarity and resolution enhance the gaming experience, too.

Starting at $139.99 for FiBBR’s five-foot Ultra Pro Series HDMI v2.0b 4K Fiber Optic cable, the line provides a wide array of lengths all the way to up 165 feet (50m). Take the next step with your 4K video system, step up to fiber optic transmission between your 4K sources and display or between your sources, audio system and your display. The cost of entry to fiber optics is finally down to earth and just in time for the holidays.

Essence For Hi Res Audio CEO Bob Rapoport can be reached at 727.580.4393 or by email at bob@essenceelectrostatic.com.

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