Siri doesn't know which speaker I'm referring to

I've now reported this to Apple as a HomePod bug. It might help if others did the same.

Since my posting, I did discover that my iPhone and HomePod were using the 5GHz wifi network and my Sonos speakers are on 2.4GHz so I changed my iPhone to 2.4GHz. iOS used to warn when a HomePod and mobile device were on different WiFi networks and prompt to change. This doesn't happen with iOS 15.

Furthermore, accessing the Home app, long clicking on the HomePod and accessing settings shows the HomePod MAC address and not the wifi channel. I discovered that tapping toggles to show the wifi channel which IMO is more informative but the default is the MAC address. After switching the iPhone to 2.4GHz I reset my HomePod as a new device and set it up again because it will use the same wifi network as the iOS device used for setting up. The bad news is this didn't make any difference.

In the past I've always left the default name as HomePod, but now notice this is showing in light grey text. Reentering HomePod makes no difference but changing the name does change text colour to black to match the rest of settings but that doesn't resolve a Siri voice command not recognising the HomePod when moving sound output.

The work around I use is to access the Home app on my iPhone, long click HomePod to show what's current playing and tap the Airplay icon. That brings up a list of Airplay devices in range, I tap Homepod to switch on then tap Sonos to switch off. As I said before, it's clunky compared with Siri but I've not found anything else that works. I wonder if ShortCuts could help? Anyone any good at creating new Shortcuts?

I did try tt2's suggestion of changing the room setting on both my Sonos speakers and my HomePod but that doesn't work either, however, it was a good call so thanks for that.