Do I need a new AV receiver to go with my 4K TV?
If you're planning on getting a 4K TV and 4K Blu-ray player or other 4K HDMI source, and you want to use your receiver to switch video, you might need to upgrade. There are also a few workarounds.
It's probably been a while since you upgraded your AV receiver, right?
Receivers, those bulky boxes at the heart of many surround sound systems, tend to last longer than a lot of other gear. However, if you use yours not only to power your speakers, but to switch video as well -- that is, all your sources are plugged into the receiver, not the TV -- then you might have to get a new one soon.
The issue is ""="" shortcode="link" asset-type="article" uuid="82160d36-8c86-11e2-b06b-024c619f5c3d" slug="what-is-4k-uhd-next-generation-resolution-explained" link-text="Ultra HD " section="news" title="What is 4K UHD? Next-generation resolution explained" edition="us" data-key="link_bulk_key" api="{"id":"82160d36-8c86-11e2-b06b-024c619f5c3d","slug":"what-is-4k-uhd-next-generation-resolution-explained","contentType":null,"edition":"us","topic":{"slug":"home-entertainment"},"metaData":{"typeTitle":null,"hubTopicPathString":"Tech^Home Entertainment","reviewType":null},"section":"news"}"> , the successor to high-definition TV. Older receivers can't switch 4K signals, and almost none have the copy protection standards required for transmission of 4K content over HDMI, the ubiquitous connection used by most home theater gear.
Fortunately there are a few workarounds that might allow you to hang onto that receiver for awhile longer as the industry transitions to 4K and beyond. Here's what you need to know about when to upgrade, why and what you can do if you still want 4K, but not a new receiver (yet).
The problem
The main issue is this: your receiver can switch signals via HDMI up to high-definition resolution (1080p), and perhaps 3D, but unless you bought it very recently, it's not going to be able to switch 4K signals. Though your HDMI cables can almost invariably handle the higher resolutions, the HDMI-related chips inside the AV receiver can't.
In many setups which utilize an AV receiver with HDMI switching, all of the sources -- such as a cable box, Blu-Ray player, game console, and a streaming media player -- are plugged into the receiver via HDMI cables. A single HDMI cable then runs from the "monitor" output of the receiver to a single input on the TV. When you change from one source to another, for example watching TV via a cable box to streaming Netflix via a media player such as Roku, your AV receiver (not your TV) does the switching.
With 4K, the entire chain needs to be 4K compatible. So if you buy a new 4K TV, want to feed it 4K via HDMI sources, and want to switch those sources using an AV receiver (as opposed to the TV), you'll need to buy a new receiver that handles those 4K sources.
The workarounds
OK, let's say you buy a 4K TV but you don't want to upgrade your receiver just yet. You have a couple of options.
The easiest is to just skip 4K and feed the TV standard- or high-definition. The TV, and all your gear, will work fine presuming you don't have a 4K source device. You'll be stuck at 1080p for the time being, which isn't necessarily a bad thing since 1080p can still look just as good, or even better, than many 4K sources.
It's also easy enough to stream 4K from an app built into your TV, rather than from an external source. In fact, streaming is by far the most common (and the cheapest) way to get 4K content today, and most 4K TVs have 4K-capable versions of Netflix, Amazon and other apps built-in.
When you use such an app, you'll want to get audio from the TV back down to your receiver. You can do this with an optical digital audio connection, which nearly all 4K TVs have.
Or, if your TV and receiver are Audio Return Channel-compatible, you can use the same HDMI cable used for the "monitor" connection. Make sure you're using the ARC-compatible input (TV) and output (receiver), and you'll be all set. This will let you get sound from the TV's apps (like Netflix in 4K) out to the receiver. Since it's just audio, again everything will work fine.
It gets more tricky if you buy an actual HDMI-connected 4K source device. Aside from PCs the only such mainstream device available today is the Sony FMP-X10 media player. More are coming soon however, including the first 4K Blu-ray players, set-top boxes like the Dish 4K Joey and Comcast Xi4, and even gaming-centric "microconsoles" like Nvidia Shield .
It's likely that many of the first 4K Blu-ray players will, like the FMP-X10, have two HDMI outputs. The main output sends the video to the TV, and the second output sends audio to your receiver. The idea is to support AV receivers that can't pass 4K.
If the player only has one HDMI output, you can use an optical connection for audio, but then you'd miss out on the high-resolution audio options like Dolby True HD and object-based surround like Atmos. Some players may have 7.1 analog audio outputs, but these will be rare (and likely in higher-end models...that probably have 2 HDMI outputs too).
What's needed in a receiver
A receiver, in order to pass 4K, will need several things. Many receivers that claim to be 4K compatible didn't have all of these features.
HDMI 2.0: This allows passage of higher-bandwidth 4K signals. Most 4K-compatible receivers have this feature.
HDMI 2.0a: No current receiver we know about has this feature, which adds HDR compatibility. It's only relevant for select HDR-capable 4K TVs. It's possible some receivers can be upgraded to HDMI 2.0a via firmware or other methods.
HDCP 2.2: This is the biggie. It's the next generation copy protection scheme and it's required by the FMP-X10, and presumably by 4K Blu-ray players, to pass 4K video via HDMI. Many receivers last year had HDMI 2.0, but didn't have HDCP 2.2. This will likely be an issue, as it might not be possible to upgrade the firmware to allow HDCP 2.2.
A good rule of thumb is that a new 4K compatible receiver should support the same level of connectivity that your 4K TV does. If your TV has an HDCP 2.2-compatible input, then your new receiver should have HDCP 2.2 as well. If not, you'll have to resort to a workaround.
You may not have to buy a new receiver if you start upgrading to 4K gear, but it will make things easier in the long run, especially if you want to keep your current video-switching arrangement intact.
Got a question for Geoff? First, check out all the other articles he's written on topics such as why all HDMI cables are the same, LED LCD vs. OLED vs. Plasma, why 4K TVs aren't worth it and more. Still have a question? Send him an email! He won't tell you what TV to buy, but he might use your letter in a future article. You can also send him a message on Twitter @TechWriterGeoff or Google+.