Thanks. I was just googling it and stuff like this kept coming up:
"HDMI ARC is designed to reduce the number of cables between your TV and an external Home Theatre System or Soundbar. The audio signal is capable of traveling both ways to and from the speakers, which will improve the sound quality and latency of the signal."
And then I read a bit more and it talked about two way communication between a soundbar and the AVR.
If I'm understanding ARC correctly, HDMI and an audio cable achieve the same thing? Just thinking if I'm going to buy second hand, some older units may not have it.
Some parts of the above are correct. Some are confused. Some are just plain wrong.
"HDMI ARC is designed to reduce the number of cables between your TV and an external Home Theatre System or Soundbar.
We're talking about removing one cable. Generally it's an optical lead from the TV to some sort of surround system. Whether someone needed that cable depended entirely on a very specific set of circumstances.
This would be the person who
didn't use some soft of PVR (a Sky box, a Virgin box, a Freeview/Freesat recorder) as the main way they received TV. Instead, they simply used their TV as the only way to receive broadcasts, and so they wanted sound via a surround system instead of the TV speakers. This all predates streaming by a few years too. HDMI ARC was released in 2009. It's also before sound bars took off in a big way.
Think about how few people fit into that category. You've got the sort of person into AV in a big enough way to go to the trouble and expense of buying an AV receiver and speaker kit, yet they don't have Sky/Virgin or a PVR. The extra of text you quoted suggests that a whole industry invented a new way of connecting to satisfy a tiny niche market. Does that sound plausible? Or do you think that the writer is full of sh**?
One of the side benefits is that ARC reduces the cable count, sure. But it wasn't invented primarily to do this. HDMI and HDMI ARC were developed as a way to combat piracy by keeping everything wrapped up in a (semi-) secure digital connection. The rest of the features are just window dressing.
The audio signal is capable of traveling both ways to and from the speakers,
I know what the writer is trying to say, but how they've phrased it is misleading, espe ially for someone coming at this as a novice and worrying whether some of these features are life-or-death important. .
HDMI is generally a one-way connection. You have a signal traveling from a source to a destination device. e.g.
Blu-ray player -> AV receiver. Then AV receiver -> TV. Both are one-way traffic situations.
ARC is only applicable between a TV and an amplifier/sound bar. It turns what would normally be a one-way connection into two-way, but only for sound, and again, in a very specific set of circumstances. With a typical AV receiver set-up at the time ARC came out, it would be normal to have all the sources connect to the amp. The HDMI connection from the amp to the TV would carry just picture. It didn't need sound because the surround system took care of that. The TV became a monitor if you will. (Optical would handle sound from the TV back to the surround system if needed.)
One small change in AV receivers happened which altered this monitor-only situation. It was- and is still called
standby pass-thru. It's a feature that allows the AV receiver to pass a HDMI signal to the TV even it's in standby. This comes in handy when you don't need the surround sound on.
The sound via the HDMI cable for ARC is only two-way then if the audio system has standby pass-thru and if there are sources connected to the amp. When all the sources are connected to the TV then ARC is just one-way for audio.
which will improve the sound quality and latency of the signal.
Latency = audio delay. In some situations HDMI can help with audio delay (the sync between sound and picture) because it includes status communication between devices if HDMI Control (CEC) is switched on. It doesn't always get this right, and there are certain times when the delay can't be fixed, but it does help.
"will improve the sound quality" - bull crap. The sound you hear via HDMI ARC is mostly either digital stereo (2.0 PCM) or Dolby Digital 5.1 for DVD quality surround. The same signals at exactly the same quality travel by Optical. There no discernible difference. HDMI ARC doesn't improve sound quality.
ARC will carry a compressed (lossy) version of Dolby Atmos Optical can't do this. That's the only difference.
And then I read a bit more and it talked about two way communication between a soundbar and the AVR.
Not sure where you got this from but it's not right.
Where you have an AVR (AV receiver) then there's no need for a sound bar. If you have a sound bar then there's no reason for an AVR. You pick one or the other. There's no reason for both. Even if you had both, ARC wouldn't work in that situation. TV -> audio system: Yes. Audio system -> audio system: No.
If I'm understanding ARC correctly, HDMI and an audio cable achieve the same thing? Just thinking if I'm going to buy second hand, some older units may not have it.
In terms of sound transfer, mostly yes. HDMI ARC = HDMI + Optical. The exception is that Dolby Atmos is firmware blocked from travelling via Optical.
The HDMI connection also carries communication signals. As well as doing basic stuff such as waking up say the AVR when the TV is switched or switching the AVR's input selection when you switch on a different source, the communication also negotiates a common set of picture and sound standards. For example, a Sky Q box can send out 4K resolution images, but that's pointless if the TV can't handle 4K. The two devices will set the video standard to 1080p HD if appropriate. Something similar happens with audio.
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Regarding your s/h amp choices, if you buy certain used AV receiver that were upper mid-range or high-end then they'll do just fine for stereo music playback for all but the most picky listeners. The question is balancing features, performance and cost. A small budget coupled with wanting lots of streaming features is going to result in you buying a lower-end amp tat ticks all the boxes but doesn't have a decent audio pedigree.
