Upgrading your High Definition (HD) system to Ultra High Definition (UHD), sometimes referred to as 4K, can be a fun and rewarding experience. But to get the most out of your system, there are some basics to know about. What follows is a basic primer, especially for those who are interested in the Apple TV 4K.

Map Out The System

I always find it helpful to get a large sheet of paper and draw a diagram of the desired, final system. The audio and video data flow as well as the desired features can then be mapped out.

As part of this diagram, remember to think about each component of the system and the requirements each component must meet. For example, if your target is a 4K/UHD TV that supports HDR10, has a Audio Video (AV) receiver to drive multiple speakers and an Apple TV and, say, a cable TV feed, each of these components must meet the minimum specs you desire and pass the signal unimpeded to the next component in the diagram. Here’s a sample list to consider.

Cable/satellite feed and DVR

Internet Service Provider

Apple TV 4K (or Roku or Amazon FireTV)

AV receiver (optional)

4K/UHD TV

For example, if you want a UHD system that supports HDR10, each item in the flow must source or pass, unimpeded, HDCP 2.2 and HDMI 2.0a. The Apple TV 4K supports those protocols.

Some AV receivers have preferred HDMI inputs and are fully capable on some, but not all HDMI inputs. If you have more sources than fully capable HDMI inputs, one of them may be lacking the full capability you planned for. A detailed look at the manufacturer’s product spec page and a review from an experienced website, like CNET, will help.

Even if you don’t use an AV receiver but depend on the TV’s speakers (not recommended) or a sound bar (barely recommended), your TV may have the same limitations. For example, on my Sony/OLED TV, there are four HDMI inputs, but only #2 and #3 are fully capable. I didn’t realize this until the system was setup on HDMI input #1, and I looked at the settings.

The Apple TV 4K is very good at interrogating the cables and TV and then deducing their capabilities. If the TV doesn’t support the video setting you’re shooting for on the Apple TV, it could be an inferior or defective HDMI cable or the AV receiver isn’t passing the signal unaltered. Or the TV is on the wrong input or doesn’t have the right settings, as shown above. Watch for these details.

HDR

One of the key technologies that makes 4K/UHD TV so rewarding is the introduction of an HDR technology called Dolby Vision. This version of HDR goes beyond the basic industry standard HDR10. (The “10” stands for 10-bit color.) With the new 4K/UHD TVs, you’ll have 10-bit color vs. the old 8-bit color on most HD TVs.

Dolby Vision may be advertised in the specs for your 4K/UHD TV, but it may require a firmware upgrade. And if you use an AV receiver, it must state support for that in the HDMI ports. For example, my Sony Bravia/OLED has HDR10, HLG (another kind of HDR), but Dolby Vision will have to wait for an update “around the end of the year.”

Dolby Vision isn’t widely supported yet, but the very best 4K Blu-ray discs of blockbuster movies will likely support it. So if you want to future-proof your system, look for this feature.

Scaling

High Definition video (1080p x 1920) is very good. If you sit far enough from an HD TV, it will be in the retina regime. All things being equal, however, if you were to send an HD video into a UHD TV, it would cover just 1/4th of the display. To fix this, all 4K/UHD TVs have a built in scaler. The HD image is blown up, “scaled,” so that it fills the 16:9 display.

The quality of the built-in scaler will dictate how good that HD video looks on a UHD (2160p x 3840) display. For many, it will be difficult to tell the difference between 4K/UHD source content and HD content scaled up. That was my first revelation.

Of course, HD content will never support HDR, but, out-of-the-box, you may not be viewing much HDR content for starters. As a result, for your conventional HD sources, such as a cable DVR or Blu-ray player, you likely won’t be able to see the difference. Don’t be obsessed, in your early migration, about pure 4K/UHD content. There’s much to learn. Eventually, however, we’ll all be using 4K Blu-ray players and cable/satellite DVRs with (growing) 4K/UHD content.

Forgetting about the benefits of HDR for a minute, you’ll want to be mindful of the benefits of a 4K/UHD TV if you sit at the right distance. This chart shows that if you buy a 65-inch 4K/UHD TV, you’ll need to sit no further away than about 8 feet. Sitting further away will take you into the retina regime. That is, it will appear the same as HD.

I’ve measured my own sitting distance, and I’m at 8 feet from a 55-inch TV. Yet, I swear I can see a visible difference compared to my old HD plasma. The difference is especially noticeable with small text. Your own experience will depend on many factors.

This is why HDR is so beneficial. You’ll see the dramatic improvements at any viewing distance.

Next page: HDMI Cables, the Apple TV 4K and final words.