Over the years, there have been plenty of different ways to get audio into an AV receiver as part of your home theater setup. For components like DVD players, this was always fairly straightforward: You either plugged whatever you would normally plug into the TV, like stereo RCA cables or later HDMI, into the receiver, or you used a specialized digital audio SPDIF output like a digital coaxial audio or an optical TOSLINK cable.
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However, what if you wanted to send audio from the TV itself to the receiver, like if you were using the TV’s built-in tuner or just preferred to use its inputs for switching components? For that, you needed a TV with a dedicated output, and not every TV had that option. If they did, it was either RCA stereo or, later, one of the aforementioned digital outputs.
In time, though, more digital audio formats popped up, many of which SPDIF didn’t support. On top of that, Smart TVs with built-in content hubs became the norm. There needed to be a better way to get audio from the TV itself to the receiver, and thankfully, one came about with the evolution of the HDMI spec Audio Return Channel in 2009 as part of HDMI 1.4. In 2017, the improved Enhanced ARC (eARC) was released as part of HDMI 2.1. Suddenly, sending TV audio to a receiver or soundbar was as simple as making sure that you were plugging those devices’ HDMI cables — which were already feeding your TV via HDMI — into the right HDMI (e)ARC-compatible port.
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