Google Assistant, Whole Home Audio, and Volume Level Controls

[burowyako]

I've been trying to figure out how to use Google Assistant devices with my whole home audio system that is managed by Control4.  I've tried to research how others are dealing with this lack of functionality and haven't come up with much other than replacing amplifiers or trying to find some EOL'd Google Chromecast Audios.  Having already invested in very nice hardware that only seems to lack this functionality, my goal is to add to my existing system rather than replace components.  All that I'm after is, "Hey Google...play (this song)" and have it play on the much larger speakers in the room using the default music service configured in the Google Assistant.

After doing some testing, I found something that can work.  I took a Chromecast with an HDMI output, connected it to an HDMI audio extractor, and then took the stereo output into the input on my Control4 audio matrix.  In Composer, I configured the audio matrix port to switch the audio source for the room when audio is sensed.  I then configured the Google device to use the Chromecast as the default music speaker, and when using Google Assistant to play a specific song, everything works beautifully.

I am now trying to figure out the best way to deal with the volume levels.  Control4 has its own levels for the room, but the Chromecast also has its own controls.  When using the Google Assistant to change the volume level, it changes the volume of the default music speaker, ultimately being the Chromecast in this example.

To address this problem, one thought was to have Control4 set the volume of the room to something like 80 when the Chromecast is the source.  This way, the volume level doesn't have to change through Control4 and the Chromecast can ultimately set the volume level.

Is there a downside to this approach?  By all means, please feel free to poke holes in this setup and educate me if there are other options available.  It's amazing to me that more hardware solutions aren't available for what I'm after, but maybe people aren't chasing it as much as I'd think.

Any and all help is appreciated.  Thank you!

[ILoveC4]

I want this too. I think I’m going to go the route of HomeKit. 

[sonic30101]

I used Chromecast audios for a while and eventually replaced them with Sonos ports so that the jacket art and metadata showed up in c4 for the rooms I wanted hands free audio where I didn't have to do excessive playlist programing. The Chromecast to extractor setup should work but one thing you may run into is after listening to the Chromecast at 80 percent room volume and then switching to a native service even with programing when the audio source is changed and conditionals if not Chromecast set volume to x there is a split second that it could blare almost full volume before the script runs because c4 will run the source selection macro first