Using an HDTV as an HDMI Switcher

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Q My new TV has four HDMI inputs. Would I get better picture quality if I bypassed my receiver and hooked all the equipment up directly to the TV? I also plan to run a TosLink digital audio cable from the TV to the receiver for sound. Any issues there to consider? —Jose / Colorado Springs, CO

A Whether or not you’ll get better picture quality from your proposed setup depends on the video capabilities of the receiver you’ve been using to handle HDMI switching. A number of A/V receivers provide both high-quality video deinterlacing/scaling and an ability to pass-through 1080p signals with no degradation (this Marantz that Sound & Vision recently reviewed, for example). But some other models are known to reduce the chroma (color) resolution of signals passing through, or to clip above-white and below-black information at the extreme ends of the video brightness range.

You might be asking at this point, “How can I tell if my receiver makes the cut?” An easy answer is to check the Test Bench section of Sound & Vision’s A/V receiver reviews, which provides a chart with information about a particular model’s video performance. If your receiver’s video handling is shown to be sub-par, you may get better performance by connecting HDMI sources directly to the TV.

Before you start unplugging cables, however, I should add that this type of hookup scheme can create problems for audio. You mentioned using a TosLink cable to route audio from the TV to the receiver. But a potential problem with that approach is that some TVs automatically convert multichannel soundtracks to stereo for output over their TosLink digital connection, which means you’ll miss out on surround sound. Here’s another wrinkle. If both your TV and A/V receiver provide HDMI jacks with Audio Return Channel (you can verify this by checking to see if the ports are labeled “ARC”), you can also use that connection to route audio from the TV to the receiver. Getting 5.1 audio from sources other than the TV’s over-the-air tuner, or built-in apps like Netflix and Vudu isn’t gauranteed, though, since some TVs also convert multichannel audio from external HDMI-connected sources to stereo.

I wish my advice here could be more neat and straightforward, but with different TV manufacturers processing audio in different ways, the end result is going to vary based on your specific gear. Bottom line: If your current setup gives you good picture quality and consistent 5.1-channel audio, it might be a good idea to simply stick with it.

DavidC's picture

I have read the comment "some TV's convert multichannel sound to stereo for Toslink output" many times now in the pages of S&V. Is it only SOME TV's, or ALL TV's? Can anyone name one TV which does not do this? This single limitation is the reason I don't use the TV as the switcher, which would have made life easier for the rest of my family (one device instead of two). An informed contributor to online forums has claimed that this is related to royalites required by HDCP (sorry, forgot exact source). Is there any truth to this claim?