Uniti range: HDMI ARC or eARC

Does anyone know if a Uniti Star is supposed to be connected via ARC or eARC?

Trying to triage a problem where plugging in headphones with the HDMI active leads to a second lo my noise sometimes. Had the television connected as eARC.

ARC I imagine as they don’t support DD/Atmos etc so no need for eARC. eARC is backwards compatible and arc supports two channel PCM which is all you can use on Naim kit.

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Yeah it has been working fine with eARC but have set it back to ARC to see if this has something to do with the issue. Thanks.

Well, the way I understand it - doing a lot of reading in home cinema circles - eARC also helps avoid possible lip sync issues thanks to some built-in communication protocol that only works with eARC connections on both ends. This supposedly helps keeping sound and video in sync better than just ARC.

To me, that is a big advantage because I’m very sensitive to lip sync issues. I hate it actually because it really distracts me from the content. So if that’s yet another HDMI communication problem that can be avoided by having two eARC devices speak loud and clear ‘eARC-talk’ to each other, I am all for it.

If I remember correctly, the Uniti Atom had the option for an additional HDMI connector module, or what’s it called. I would hope Naim does not have too much of those in stock and that they can make eARC modules as soon as possible.

Normal ARC has a Lipsync correction built in since HDMI 1.3 came out, eARC does nothing new here other than its included from the off, some older ARC stuff might not support it as it was down tot the manufacturer. Its just higher bandwidth to allow for Atmos etc nothing more currently.

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Ah okay, I’m sorry if I passed on the wrong information, but that’s what I understood to be one of the benefits if eARC. Since the audio syncing is mandatory on eARC, there’s less chance of issues because one can be sure (as can be with HDMI) that both devices work together and understand each other.

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Yes being mandatory does help and improves standards overall. Also it doesn’t rely on CEC either had its own new protocol which again is better for compatbility between vendors as CEC I always found flakey.

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Thanks for adding some interesting info!!!

Unfortunately I am still getting the sound using just ARC.

So is it just there when using Headphones and ARC no other time?

Yeah it appears that If I use ARC for a time and then plug in headphones there is a sound for a second or so. But not always. It’s a pretty nasty one or figure out.


Not using HDMI on my Atom; but when I shut-down TV (connected via SPDIF), while the input is still active, I get a split-second of “noise” from the Atom.
But your scenario sounds different - only after longer sessions and longer tone (about a second; mine is very short).

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You know it’s shorter than a second. Was trying to say that it isn’t long hehe.

But I can do better than that! I recorded it yesterday. Plonked it on here https://sndup.net/4s63/Naim+headphone+sound.m4a

Some background noise there but it’s the short zzzt like sound right at the start. How much does that sound like what you are getting?

Yes, this is very similar.
(Don’t get a dropbox link to work yet; keeping trying.)

I actually got this “always”; I just assume, that just before the Atom detecting “loss of signal” there a bit of “noise” coming along the fiber due to the disconnect on the other end. (So, potentially different triggers, but essentially a similar “glitch”, like from a distorted buffer of a digital input.)

PS: I adjusted, by either ignoring the blip (on normal TV listening volume, I don’t think it will hurt speakers or ears). Otherwise I make sure to reduce volume, switch to another input first, or turn the Atom to standby first.
But of course, having this “fixed” would be more convenient.

Hmmm well this is comforting to hear. Not that you also experiencing it but my first concern with something like this is hardware. If you getting something similar it’s probably firmware.

It appears now that if something is actually playing on the HDMI and I plug in headphones under similar conditions as before there is no sound. Seems just when it is idle.

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