HDMI to digital active speakers. Why is this so hard?

[Roland68]

I'm currently designing a new home cinema/hifi system for my living room.

On one end: an LG OLED TV with an HDMI eARC port. (I'm hoping the TV can always output LPCM to avoid format compatibility issues down the chain, not sure how well that assumption holds…)

On the other end: a set of what will likely be Genelec SAM monitors, possibly 8341. 5.1 multichannel setup.

Interconnecting consumer AV equipment and active monitors has always been a bit of a nightmare, especially in multichannel. Nevertheless, I can't believe that it's 2025 and there is still no clear, cheap, straightforward, hassle-free to connect these two things.

Genelec SAM monitors have AES/EBU digital inputs, so it's at least theoretically possible to keep the signal digital all the way to the speaker itself. I say "theoretically", because converting HDMI to 5.1 multichannel AES/EBU signal pairs seems much, much harder than it should be. Almost all products output a single S/PDIF stream which is not good enough as S/PDIF can't carry LPCM 5.1.

I am taking suggestions. This is what my research turned up so far:

• Audiopraise VanityPro: ticks all the boxes, but expensive - especially given it's just a basic converter, nothing else - and hard to source (looks like I would have to import it to the UK). Unclear how well it works day to day in practice.
• Some incredibly obscure chinese "HDMI to 4AES" device. Only available on AliExpress, docs are in chinese, unclear if it works with ARC, need to build your own cable to go from the DB25 pinout to XLR, sounds fun! (Not really)
• Trinnov Altitude 32, Storm Audio ISP Evo: the price tag on these things is utterly bonkers (£15k+). It would cost more than all the speakers combined!
• I've seen some people describe some unclear arrangement involving Meridian hardware, something to do with their SpeakerLink format, but couldn't quite figure out exactly what they were doing.

One thing to keep in mind is I absolutely need this to work with ARC. There is no way I'm inserting a device in the middle of the chain - these tend to cause all kinds of issues with HDMI handshaking, future-proofing given increasing HDMI bandwidths/capabilities, etc. my friends have been bitten too many times for me to even consider this. Not to mention this won't work when the TV itself is playing content. There is this weird product that can apparently make any HDMI input ARC-compatible, but I'd prefer to avoid such schenanigans if I can avoid it.

If no-one has any better ideas I'll probably just give up, slap a MiniDSP Flex HTx on it, accept the pointless additional A/D-D/A conversion that this would involve, and have fun troubleshooting ground loops and other EMI noise issues. Sigh. (By the way, is there a cheaper product that also does HDMI to balanced analog out?)

There's also a DIY option, probably very inexpensive.
You could tap the internal I2S signals from any AV receiver (used ones with Atmos start at €250-300) before the DAC ICs and convert them to AES without loss. The cost of the equipment is likely to be €80-200.
The rest of the AVR's functionality, including ARC and eARC, is retained.

 

[terryforsythe]

Sadly the only thing that's missing from the SW42DA is EQ/room correction capabilities.

You probably could use CamillaDSP running on a Raspberry Pi as your solution.

You also would need an EARC/ARC to Digital Audio Converter, e.g.: https://www.orei.com/products/hdmi-..._hg1gpzrCoLouHUuT0gSTyjit09e5TiaYxv6FwEi9uXfu

and digital I/O for the Raspberry Pi, e.g.: https://www.minidsp.com/products/us...Z-VFsS6fiRF3BD9lJlMI2qgwnOQ3e70JdZ2O6M2lDvO-d

The setup would be like this:

TV --> EARC/ARC Converter --> MCHStreamer input --> Raspberry Pi --> MCHStreamer output --> Digital Speakers

That would give you a lot of flexibility and EQ capability using DSP, and the whole setup shouldn't cost more than $250, but it is not as clean as using a single box solution. Also, the MCHStreamer Kit does not come with a case, and you need to provide your own RCA connectors for SPDIF coax out. I have a case already designed for it for 3D printing. I could modify it to add more holes for the output connectors and send the .stl files to you if you have, or know someone who has, a 3D printer.

 

[MCH]

You probably could use CamillaDSP running on a Raspberry Pi as your solution.

You also would need an EARC/ARC to Digital Audio Converter, e.g.: https://www.orei.com/products/hdmi-..._hg1gpzrCoLouHUuT0gSTyjit09e5TiaYxv6FwEi9uXfu

and digital I/O for the Raspberry Pi, e.g.: https://www.minidsp.com/products/us...Z-VFsS6fiRF3BD9lJlMI2qgwnOQ3e70JdZ2O6M2lDvO-d

The setup would be like this:

TV --> EARC/ARC Converter --> MCHStreamer input --> Raspberry Pi --> MCHStreamer output --> Digital Speakers

That would give you a lot of flexibility and EQ capability using DSP, and the whole setup shouldn't cost more than $250, but it is not as clean as using a single box solution. Also, the MCHStreamer Kit does not come with a case, and you need to provide your own RCA connectors for SPDIF coax out. I have a case already designed for it for 3D printing. I could modify it to add more holes for the output connectors and send the .stl files to you if you have, or know someone who has, a 3D printer.

The problem with this is how to decode the 5.1 signal (dts typically) out of the extractor with the RPI.

 

[terryforsythe]

The problem with this is how to decode the 5.1 signal (dts typically) out of the extractor with the RPI.

Perhaps it won't work, I don't see DTS listed for the MCHStreamer.

 

[terryforsythe]

The problem with this is how to decode the 5.1 signal (dts typically) out of the extractor with the RPI.

The OP mentioned using the miniDSP HTx, but it's manual states:

"REMINDER: Please note that the Flex HTx does not support bitstream (e.g. Dolby/DTS) decoding. The audio source must be able to output linear PCM (LPCM) for multichannel support over HDMI."

So, if DTS is needed, the miniDSP HTx also will not work. But, if the miniDSP HTx would work for the OP using PCM, then the solution I proposed also should work. Both the ARC/EARC converter and the MCHStreamer kit also support PCM.

 

[MCH]

The OP mentioned using the miniDSP HTx, but it's manual states:

"REMINDER: Please note that the Flex HTx does not support bitstream (e.g. Dolby/DTS) decoding. The audio source must be able to output linear PCM (LPCM) for multichannel support over HDMI."

So, if DTS is needed, the miniDSP HTx also will not work.

There are a few possibilities, mentioned often in these threads:
There are TVs or TV boxes capable of sending multichannel lpcm via hdmi (example certain apple TV box). That would work with the flex.

But to the best of my knowledge, multichannel via toslink/coax is limited to encoded and compressed formats, no matter what, so you will need to decode that signal somehow.

 

[edechamps]

You probably could use CamillaDSP running on a Raspberry Pi as your solution.

I am worried about the audio latency that would be induced by having a general-purpose computer in the middle of the chain, which is not normally designed for reliable real-time low-latency DSP.

You also would need an EARC/ARC to Digital Audio Converter, e.g.: https://www.orei.com/products/hdmi-..._hg1gpzrCoLouHUuT0gSTyjit09e5TiaYxv6FwEi9uXfu

That product page is grossly misleading - it mentions "eARC" and "PCM 5.1" which is impossible as S/PDIF does not have the physical bandwidth to support anything more than compressed formats (basic DD/DTS) when using >2 channels. Most likely it's doing shenanigans like downgrading everything to basic DD/DTS (or worse, downmixing PCM 5.1 to PCM 2.0), which involves quality degradation and also assumes the sink supports these formats.

The whole reason why we are discussing products like the AudioPraise Vanity Pro, the Blustream SW42DA and the Nuprime-X H16-A is precisely because they are capable of outputting a lossless 5.1 signal.

 

[terryforsythe]

The whole reason why we are discussing products like the AudioPraise Vanity Pro, the Blustream SW42DA and the Nuprime-X H16-A is precisely because they are capable of outputting a lossless 5.1 signal.

Then you definitely should get one of those.

 

[kfrancis]

The correct way to do this is to go from eARC to Dante or AES67 then in to a Genelec 9401A and thence in to the SAM system over AES. This will allow you to do bass management and room correction entirely in the Genelec world using GLM.

AES3 carries a stereo signal each speaker just ‘listens’ to the one it wants and you connect them with standard AES cable with XLRs on it.

The sub is special that does use both audio channels a SAM sub being managed with GLM takes the LFE on one channel and a sum of all the other inputs on the other channel provided by a 9401A or a 9301B. The bass management and other correction is done in the speakers and the subs DSP controlled by GLM.

Incidentally, what this means is that in practice you don't really need a Genelec 9401A or 9301B in particular. You just need some way to send the subs a sum of the bass managed channels.

I use a DAD Core 256 for this (via some PoE Dante AVIO AES3 adapters). It's not as straightforward as a 9401A would be, but it works very well, and it offers additional flexibility. For example, I have the Core 256 connected to a Mac Mini M4 via Thunderbolt as an audio interface. It sums the channels from an Arvus H2-4D and the Mac's own 7.1.4 output, so I can listen to either HDMI sources or the Mac or both with no fuss. I can send a stereo fold down of this output to (future) Dante in-ceiling speakers in other rooms. I can mute certain channels easily in DADman, and so on.

DAD and others have similar Dante/AES67 products with (optional) AES3 outputs that could fully replace a 9401A, but they're pricier.

I'd only recommend this route if you really enjoy tinkering with this kind of thing. It's definitely not plug and play.

 

[MagnusB]

The Meridian 271 maybe?
Make your own cables to remap ethernet to whatever input the speakers require.
Not sure if the additional Meridian communication over "Speaker Link" will interfere or not. But if you set it to not be a controller I suspect there is nothing sent.

 

[Esprit]

have the Core 256 connected to a Mac Mini M4

It's a shame that the Apple mini doesn't play Dolby Atmos (which is absurd considering the Apple TV can do it).

 

[chelgrian]

It's a shame that the Apple mini doesn't play Dolby Atmos (which is absurd considering the Apple TV can do it).

It can in some situations see

About HDMI Passthrough

Learn about using HDMI Passthrough.

support.apple.com

The limitations are to do with Dolby Licensing and are not technical.

 

[Tre2023]

The Mac mini can bitstream/Passthrough Dolby Atmos from the Apple TV and Apple Music apps. It cannot convert to LPCM and retain the Atmos metadata like the Apple TV 4K and the Apple TV 4K cannot Bitstream/Passthrough Dolby Atmos.

 

[kfrancis]

It's a shame that the Apple mini doesn't play Dolby Atmos (which is absurd considering the Apple TV can do it).

It can output pre-rendered Atmos as discrete channels to a supporting audio interface (like the DAD Core 256), but it's limited to 7.1.4, unfortunately. As @chelgrian mentioned above, Apple Music can output it over HDMI "passthrough" now, I think in a similarly jank way as the Apple TV does.

 

[kfrancis]

Apple Music can output it over HDMI "passthrough" now, I think in a similarly jank way as the Apple TV does.

The Mac mini can bitstream/Passthrough Dolby Atmos from the Apple TV and Apple Music apps. It cannot convert to LPCM and retain the Atmos metadata like the Apple TV 4K and the Apple TV 4K cannot Bitstream/Passthrough Dolby Atmos.

Oh, maybe it is, in fact, less jank. It's still DD+ JOC or whatnot rather than something lossless (TrueHD). But the actual media seems to be delivered to Apple in a lossless format, so they could eventually support it.

 

[Esprit]

I wrote a stupid thing, the Mac mini plays Dolby Atmos with limitations, but it does not play Dolby Video.
That's why it is sitting on the store shelf for now.

 

[Tre2023]

Unfortunately, it will not output Dolby Vision unless connected to Apple's own monitor. Though, it can Airplay Dolby Vision and Dolby Atmos to a capable TV. Silly.

 

[chelgrian]

Unfortunately, it will not output Dolby Vision unless connected to Apple's own monitor. Though, it can Airplay Dolby Vision and Dolby Atmos to a capable TV. Silly.

Oh good grief:

Apple TV is licensed to do everything essentially as it is a closed device which you cannot run arbitrary software on. In general it does this by decoding an outputting Dolby MAT2 which in this case is a PCM format + Metadata . This is not ‘jank’ and many Blu-ray players do the same.

macOS can:
- Output discrete Atmos to speakers from Apple Music *only*.
- Pass through EAC+JOC on to HDMI from the Apple TV App and QuickTime Player.
- Output HDR10 from any HDMI output on Macs from 2018.

All of the restrictions are due to the requirements of or cost of licenses from Dolby *not* technical restrictions.

If you want to get annoyed then complain about Dolby rather than calling things ‘jank’.

The way AirPlay works in this case the remote device is actually downloading the data and also displaying it, it never goes through the Mac which is why Dolby allow it to Atmos/Vision.

 

[Esprit]

With the iPhone I can record in Dolby Video, I can edit it, I can't play it on a video projector.
How do I play it through the Apple TV?

 

[Tre2023]

Oh good grief:

Apple TV is licensed to do everything essentially as it is a closed device which you cannot run arbitrary software on. In general it does this by decoding an outputting Dolby MAT2 which in this case is a PCM format + Metadata . This is not ‘jank’ and many Blu-ray players do the same.

macOS can:
- Output discrete Atmos to speakers from Apple Music *only*.
- Pass through EAC+JOC on to HDMI from the Apple TV App and QuickTime Player.
- Output HDR10 from any HDMI output on Macs from 2018.

All of the restrictions are due to the requirements of or cost of licenses from Dolby *not* technical restrictions.

If you want to get annoyed then complain about Dolby rather than calling things ‘jank’.

The way AirPlay works in this case the remote device is actually downloading the data and also displaying it, it never goes through the Mac which is why Dolby allow it to Atmos/Vision.

I was not the one that said “jank” about anything and I’m not actually really annoyed.

There is not a blu-ray player out there that can decode Dolby Atmos or DTS:X and output PCM while also retaining metatdata. They must be bitstreamed.

Dolby Atmos from Apple Music in macOS is available using Passthrough over HDMI. If not set to Passthrough, Atmos metadata is not sent in the multichannel PCM signal like it is in the Apple TV 4K.

While Airplay can handoff Apple Music content to an Apple TV 4K, this is not the case when using Airplay to cast a movie to a supported TV. This is my experience anyway.

Back to using the Apple TV 4K with the Flex HT, it is still the best streaming device for the job. A blu-ray player set to output everything in PCM would also work for those wanting to spin discs as they can decode and output multichannel PCM. In either case, the TV must support eARC.