There is the HD Fury Arcana, the Feintech VAX04101k, and the latest, is the OREI HDA-935. You can also order from those links from the companies directly, or check your local retailers for availability. Amazon may carry some, depending on location.
 

Any of those three will act a a eARC splitter on the incoming HDMI signal and give you Atmos, assuming the source is in Atmos. 

@Airgetlam, I do appreciate for your instant answer!

HDfury Arcana is much more expensive than the other two devices, while it has just one HDMI input port. Do you know if there is any difference regarding the audio and video quality among them?

Is it possible to use one of the above HDMI adapters to connect my EPSON EH-TW9400 projector (I repeat, no HDMI output or optical port - consider it as a simple 4K PC monitor), my sonos system and a TV BOX (for examble Nvidia shield pro - it provide dolby atmos and 4K video) and this setup will be capable to give dolby atmos sound and 4K video?

If I use as a source, my laptop or PC, instead of the TV BOX (Nvidia shield pro) will I get dolby atmos sound and 4K video?

I’m a “newborn” in home cinema world, so please forgive my detailed or rephrased questions. I just try to firuge out which is the best solution, avoiding waste money and time.

Thank you in advance!

No, I don’t, although HDMI 2.1 is a digital medium, as is eARC, I’d assume they’re all essentially the same, both for audio and video. 

Not sure I understand your second question. These devices sit between the source, which generates the HDMI, and the TV and Arc. Your audio and video come out of these devices. So if the source is generating an Atmos signal, that will be sent to the Arc. The same for any 4K video signal.

Does that answer your questions?

No need to apologize for being a “newbie”, we’ve all been one at one point or the other. Just want to be sure I’m answering the questions you have properly, and that the answer is understood. 

With an HDMI-ARc capable TV sounds need to go from your TV to the soundbar, via the Audio Return Channel. Normal (non-ARC) HDMI just sends video (and audio to the TV, or in your case to the projector (wheere you only need the video - the audio goes from the Shiled through the Arcana/Feintech/OREI straight through to the soundbar.

I have read at least the Arcana needs to be set up with a HDMI-ARC capable TV first. Aftre this set up it can be used with a projector.

I’m very grateful for your answers! They are very helpful!

Last but not least, I’d like to ask about HDMI cables (just to be sure).

Anyone about the HDMI cables? Please!!

You may want to read up on HDMI cables on wikipedia, which might tell you if 4K requires HDMI 2.1 or not. I don’t recall offhand, which is why I would encourage you to do the research yourself.

On the other hand, I’m not really sure that you can purchase HDMI 2.0 cables anymore. 

I would not be using an optical cable. The bandwidth available would then stop you from using anything other than Dolby Digital. 

Thank you for your answer!

There are many HDMI 2.0 available in the market. As far as I understand reading wiki and more, HDMI 2.0 can carry 4K video at 60 Hz.
So, in order to reduce the cost of the HDMI cables for Nvidia shield and the projector (10m away from the arcana), I think it’ better to buy 2 piece of HDMI 2.0 than HDMI 2.1 which is much more expensive.

The fiber optic HDMI cable can be used to connect Epson EH-TW9400 to Arcana to carry video, not audio. I thought may be better because of the 10m distance.

For the Sonos Arc, I suppose I must use HDMI 2.1 to connect it to Arcana, right?

Not sure, perhaps you might ask the HDFury folks, they’d know. 

For me, it’s always valuable to have the latest version, for things that may come up in the future, but may not necessary quite yet. There’s no value to me in having to purchase yet another cable, when I could have just spent a little more initally….but much less than the cost of fully replacing it. 

That being said, I think the current HDMI cable shipped from Sonos is 1.4, although that’s an assumption on my part. 

I asked the folks from HDfury but unfortunatelly they don’t know… Disappointing…

Let me ask another question.