Audio and Video setup

[Tigers_Ghost]

Hello all.
I need some help getting my complicated room setup working well. I'm not sure how best to make this work, and I've had some problems so far.

What I have is:
Shelf and Desk setups that will need to work well with each other.
I have a shelf with a TV and 4 HDMI devices.
And a desk with 2 computers, and 2 monitors. Main computer uses both screens unless I want to use 2'nd computer. There's a HDMI hub going to the second screen.
A cable going between shelf and desk would be about 10 meters.

What I want is:
To be able to have audio to my headphones and speakers coming from my 2 computers independently.
To be able to use any of the 4 HDMI devices on my TV and also on my second monitor at the desk.
And of course to also have audio from those devices both on my TV and on my desk speakers and headphones.
So I could for an example use my headphones while sitting at my desk, using one computer and one of the consoles at the shelf on the 2 monitors.
Also to make sure there is as little audio noise as possible from the cables, it has been annoying me a lot so far.

Things I should mention...
I have an Onkyo TX-NR737, it basically serves as an overkill HDMI hub, but it's causing some problems with HDMI and audio output for how I want it. Been wondering if I could have something smaller that draws less power and is less overkill since I don't have a home theater setup, just the TV speakers, might get a soundbar or something.
I ran a 3.5mm cable from Onkyo to my computer but its making noise.

Let me know about any relevant info I didn't include.
Hopefully someone has a good suggestion for what I need to connect everything well.

Thank you all.

 

[americanaudiophile]

A 4x2 HDMI matrix switcher would allow you to send any of the sources to either or both the TV and HDMI input selector for the 2nd desk monitor. Different sources could go to each. No need for the receiver now. You will need a good 10m HDMI cable.
The audio is a bit more complex and depends on whether the 2nd monitor has an audio output. If it does then you would connect that and both PC audio outputs to an audio input selector. That would output to your headphones and speakers. You may need a headphone amp and the speakers would be self powered.
An HDMI audio extractor would be needed if the 2nd monitor doesn't output audio. That would connect in between the input selector and monitor.
A stereo mixer would be required if you wanted to hear more than one source at the same time.

 

[Tigers_Ghost]

A 4x2 HDMI matrix switcher would allow you to send any of the sources to either or both the TV and HDMI input selector for the 2nd desk monitor. Different sources could go to each. No need for the receiver now. You will need a good 10m HDMI cable.
The audio is a bit more complex and depends on whether the 2nd monitor has an audio output. If it does then you would connect that and both PC audio outputs to an audio input selector. That would output to your headphones and speakers. You may need a headphone amp and the speakers would be self powered.
An HDMI audio extractor would be needed if the 2nd monitor doesn't output audio. That would connect in between the input selector and monitor.
A stereo mixer would be required if you wanted to hear more than one source at the same time.

Thank you! I didn't even know something like a HDMI matrix existed, seems perfect for me. Now I just need to find a good one...
I've checked some and some have SPDIF out, if it works how I hope it does, I could just run that along the HDMI cable to my desk, if not then as you said, HDMI audio splitter it is.
2'nd monitor has a 3.5mm audio jack but its too quiet.
And running digital cables instead of analog anywhere I can sounds like a good way to reduce noise.

This solves my main problem, another thing I didn't mention is that my main computer has a sound card SoundBlaster ZXR, so I can connect everything there probably. But as you mentioned, some form of stereo mixer or external sound card would be useful since as I have it now, the main computer needs to be on for the for the 2'nd computer or anything from the shelf to make sound at the desk.
Ultimately, I'd like for main, secondary and shelf sound to be at the desk speakers and headphones without any noise.

Thank you again.