Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Using an HD621 with a 4K screen

Hi
My system currently uses an HD621 for all HDMI inputs and I currently just use my tv as a “monitor” from the HD621. The audio is extracted by the HD621 which feeds my 861. In this configuration the HD621 performs both HDMI switching and audio extraction duties.

Since the HD does not support 4K HDMI signal if I ever get a 4K screen, could an alternative arrangement be to use the 4K screen as the HDMI switcher and use ARC HDMI audio out to feed the 861 for Meridian audio ?

This relegates the HD621 down to audio extraction duties from the out signal from the TV with HDMI switching going to the TV.

Would this congregation work or am I missing some ARC to HD621 compatibility issue?

Thanks
/Marcus

Hi Marcus,

While I'm happy to be corrected by someone, my understanding is that the HD621 relies on the source (e.g., Bluray player) being set up to output 5.1 or 7.1 PCM and I don't think that a TV would 'pass thru' that multichannel PCM from the Bluray player.

Brian

Thanks for the reply Brian,
I thought the whole point of an HDMI ARC was to carry that information?
Is that where I am going wrong in my understanding?

/Marcus

I am pretty sure that for HDMI ARC to work, both devices need to support it. The HD621 does not. The UHD722 does but it is only 2 channel stereo.

Hi
So if I read this correctly, does it mean that HDMI "ARC" is not simply "seen" as an HDMI "source" by the HD621...

Also, stupid question but how does one ever get a multi channel audio signal out of a 4K TV?

/Marcus

In every case I have come across, no.

Depends on the TV. Most will output at least 5.1 on optical. Some can do much more with ARC but it depends on what the two connected devices negotiate on the handshake when connected. It usually ends up as the best that the two devices agree on.

Hello Marcus,

I have used a Connect AE24 UHD 2.0 - HDMI audio extractor 4K HDR | ARC to send 5.1 PCM from an Xbox One S to my HD621 and send video to my TV (it wasn't a 4K TV, but the video output on my HD621 doesnt work!)

I recently upgraded to an Xbox Series X and a 4K Panasonic OLED and can confirm that the Connect AE24 UHD 2.0 does pull Dolby Digital via ARC from the TV and sends it to the HD621.

I have even more recently purchased a PureTools eARC Audio Adapter, Splitter and Extractor and this pulls 5.1 PCM, from the TV via eARC.

When I connected the Pure Tools eArc adapter and turned on my xbox, as if by magic 5.1 pcm appeared in my 861!. The xbox was set up to output dolby digital...What I believed happend is that the Pure Tools read from the HD621 that it wants 5.1 pcm and then told the tv, which in turn informed my xbox because when I checked the settings in the Xbox it was already changed to uncompressed 5.1.

I have just checked on my Oppo 103D 5.1 PCM from decoded Dolby True HD / DTS-HD is also set via eARC from tv to HD621.

So to answer your question you will need a device in front of the HD621 to tell your tv it is an ARC/eARC enabled device.

This also does the same kind of thing as the Pure Tools eARc Adapter.

Hope it helps

Hi,

Thanks to Bruce and Frank for your comments, I’m not well up to speed on things about ARC. However, as far as I can see, Meridian are well behind with all of this. From what I’ve read, eARC will get you 7.1 out of the TV (from the source) to a processor, but as Bruce says the UHD722 is only 2 channel capable.

Obviously some 4k Bluray players do have 2 HDMI so you can get audio into a HD621 that way.

Brian

Thanks for the responses.

So let me summarise my understanding here:

1. ARC and eARC will kick out high res audio from a TV (source) (that is , compared to TOSLINK two channel with can kick out stereo and potentially compressed 5.1 anyway)
2. There is a "negotiation" on the ARC/eARC that determines what the "(destination)" is capable of receiving.
3. The HD621 is not able to "negotiate" over ARC so is likely not to receive anything.
4. If one adds a "PureTools eARC Audio Adapter, Splitter and Extractor" for example and connects that directly to the TV then then it will handle the "negotiation" on behalf of the HD621. The negotiated signal can then be output to the HD621 which allows the HD621 to receive signals from the TV that it would otherwise not be capable of doing.

If that is all correct, my next question would be in trying to understand the limitations of the HD621/861v4 parts of my chain.

According to WHAT-HIFI HDMI ARC and EARC everything you need to know.

eARC can handle Uncompressed 5.1, uncompressed 7,1, and High bitrate and object based signals (Dolby Atmos, DTS-x etc.).

Questions are then:
1. Can HD621/861v4 chain handle the uncompressed signals anyway? Or is that part of the chain the bottleneck anyway so the "best" I can get is compressed 5.1?
2. If it can't receive anything more than compressed 5.1 over the ARC cable, then why bother with ARC at all, why not just use the TOSLINK?

Thanks in advance
/Marcus

Good, clear analysis Marcus, if I may say. I find much of the changing technology initially confusing, partlly because it is so often poorly explained - discussions seem to start in the middle, not at the beginning, and terms are used ambiguously. So a relief to see your last post, even if I cannot say if your are correct. The right questions, it seems to me. Perhaps this could form the basis of a Wiki article when all is resolved?

Regards, Locus.

The HD621 does not do any decoding on it’s own (Dolby Digital, DTS, etc…). It accepts LPCM over HDMI, extracts that signal, and passes it on via 3x SPDIF or MMHR on RJ45. For 3x SPDIF, the maximum is 6 channels, so 5.1. The MMHR connector can output 8 channels, so 7.1 is possible.

MMHR is only available on the 861v8. For the 861v4, you’re limited to using the MD1 or MD2 inputs, which would be 5.1.

Cheers

OK understood now I think.

1) An inbound signal to an HD621 can be thought of as having separate VIDEO and SOUND channels. The HD621 extracts the SOUND channels from the feed. It is capable of extracting up to 8 UNCOMPRESSED channels from the signal. It extracts the VIDEO channels also from the feed and sends them out to a monitor attached to the "HDMI OUT" socket.

2) Scenario 1: Connection of a 861v4 to HD621 using the three RCA plugs. Since each each plug can take two uncompressed channels the maximum number of channels extracted and fed to the 861 would be SIX. This would be fine for uncompressed 5.1.

3) Scenario 2: Connection to a 861v6 using RJ45. When thus connected, the HD621 can deliver up to 8 uncompressed audio channels to the 861. This means it could handle uncompressed 7.1 for example.

4) The audio channels are there as conduits for the audio and do not define the type of multi channel encoding used. The same audio channels here discussed can be used for a variety of different encoding systems, however, the decoding algorithm must be supported by the 861 for the audio to be delivered correctly to the speakers.

Did I get this right?

Thanks guys
/Marcus