I had assumed your chromecast received a good signal from the AP, if that was the case switching the location of the AP to beside the chromecast should give a good signal in the original AP location. Itís now just sending it back to where it originally was.
Given you have moved the AP besides the chromecast, and now WiFi is poor where the AP originally was, this must mean the signal from the original location to the chromecast was also poor.
You may have just identified the issue all along.
The chromecast audio has very weak internal WiFi and you need a good signal to it.
You need to ensure you connect the APs with Ethernet for best performance and that signal is adequate to the chromecast. Ideally ensure -70RSSI or better throughout the property.
Your issue generally sounds like you have inadequate WiFi coverage around the house, and connecting with homeplugs isnít helping either.
If you inagine all traffic must go via the original router, you donít want a slow homeplug which may drop out in the middle, unless you know your home wiring is perfect.
Connecting the chromecast audio with Ethernet is just a band aid, hiding the fact the WiFi signal is inadequate in that location, fix the real issue which is poor WiFi. What happens when you want to add something else like a smart tv or new technology in future, or perhaps use an iPad in the weak signal area? Itís much easier to hop onto a good WiFi network, for example I can get 400Mbps all over my home on wireless, so I donít need to wire anything in. I have 4 access points around the home, and I use a mesh wireless network similar to the BT whole home wifi (its an option for you, itís wireless but expensive). What Iím saying is once you get it right it just works.
Edited by ukhardy07 (Sun 24-Dec-17 05:15:14)