[FIXED] Basic audio routing confusion - help for a beginner needed.

Firstly hello guys this is my first post.
 
History
I'm starting game development as a more serious hobby. With that in mind I decided a DAW would be a nice distraction to play with in the evening to unwind and useful later on down the line when in came to the audio side of things for my games developing. 
 
I purchased Sonar Steam edition then later upgraded to the Profession Edition. I'm using Windows 10 and my PC Audio hardware is a Focusrite 6i6 & a Novation Launchkey Mini.
 
My situation
I have my PC kit in the living room and in the evening I use headphones for Sonar but in the daytime will be using my Cinema Amp. I have been watching some tuition vids from CakeTV & other sources. At the moment I wear a small set of in ear phones plugged into my PC soundcard to hear the video commentary and a set of cans over the top to hear my Sonar when I want to pause the vid and try something out. Its less than ideal. I have tried messing around routing audio via Windows Control Panel but I get issues with the Focusrite needing to be used exclusively by Sonar which is reasonable & crashing when I try to force things.
 
I though using hardware signal routing may be a better option so I purchased a couple of SPDIF converters which I setup the following way...
 
To get the sound from my PC to the Focusrite:
PC SOUNDcard SPDIF optical out  ---- > CONVERTER ------->   SPDIF Coaxial Focusrite IN   
 
To get the sound from the Focusrite to my Denon Cinema AMP 
SPDIF Coaxial Focusrite OUT  ------->  CONVERTER ------>  Cinema AMP optical in
 
I can now hear audio from a video playing on my PC through my Cinema AMP and adjust the level in the Scarlett MixControl. Screen shot shows how I have it setup and what is selected in Windows control panel.
 

 
Step 1 ok.
 
I leave the video playing and launch Sonar. The videos audio stops coming out through my Cinema amp. If I hit a note on a soft synth that does come out of the Cinema amp. Below is a shot of the mixer again. Just set as before.
 

 
I understand that Sonar will take control of the routing on the Focusrite but how do I bring in the sound from my video which is connected to the FocusritesSPDIF Coaxial Focusrite IN? I have looked at adding a track like you would for say an electric guitar and try to use the 'FocusritesSPDIF Coaxial Focusrite IN' as the source but I am not sure if I am going about this all the wrong way.
 
All I want to do is watch some CakeTV videos and play along with them.
 
Sorry if this is such a basic question but I am unsure if what I am doing, and how Im going about, is the best or correct way and the videos I have watched so far have not helped.
 
Thank you for any help you can give.
 
Regards, Paul
 
 
 
 
 
Windows 10, Sonar Professional ver 21.12, Scarlett MixControl ver 1.8
 
 
 
 
 
 

Thanks for getting back with the suggestion Zargg.
 
I checked the settings you suggested and still no joy. In fact using them and allowing the 6i6 driver to be shared in the Windows SOUNDS settings caused Sonar to crash sometimes.
 
I tried everything and made a big long list with screen shots hoping I would fix my own problem on the way. In the end I gave up and just used an analogue cable from the speaker out on my PC soundcard to and input on the rear of the 6i6. This worked first time without issue so I can hear a tuition video and play with Sonar in one set of headphones . Its not ideal but at least I can do what I need to now.
 
Thanks again for your time, Paul

I'm not sure I'm understanding the issue here, but what if you bring the video into Sonar via the import menu. That way said video is running from within Sonar and you won't be trying to use two programs at once. Like I said. I'm not sure I 'get' what you're trying to achieve, but it's what I do with songs I want to play along with.

Hey... lookit. A post where my crazy long Voicemeeter vid might actually be of use.
 
https://www.youtube.com/watch?v=SXEtm5_M9HI
 
You can pretty much ignore a whole pile of that faff because it's about setting up Mirillis Action! to record Sonar BUT I go into great detail of using VBAudio Voicemeeter (which is free to use... well donationware anyway) to route audio around in all sorts of wacky ways and how to set it all up on your system and inside Sonar.
 
If you click the "Show More" thingie in the youtube video description it will expose all the navigatble chapter links. Of interest for your purpose would be the Voicemeeter setup and descriptions and how to route Sonar into Voicemeeter.
 
I use a Focusrite Scarlett 18i6 which uses the same interface software/drivers so it should all be reasonably similar.
 
Essentially you could use Voicemeeter as a virtual ASIO mixer inside your system to route everything as you bounce back and forth between the programs. Then when you are ready to do some actual music stuff switch back to the proper Focusrite drivers (although Voicemeeter will still work anyway... it just may not be as stable for high resource consuming audio tasks).
 
It is a REALLY long vid though so definitely check out the relevant chapters instead of plodding through the entire thing.
 
Might help. Might be overly complicated. Might be a bunch of crud in between.
 
Either way...
 
Cheers and welcome to the forum.