I have multiple old Harmon Kardon Invoke speakers. Previously Cortana devices, but now just bluetooth speakers. After looking at some of the info around Assist and voice preview edition makes me wonder if the Invoke could be re-flashed to work with HA. They have good sound and good microphones. Wondering if anyone else has thought about or looked into it?
You may run into trouble with the Bluetooth bit - HA does not pair with Bluetooth speakers.
I found this github repo, but it doesn’t look like much happened. coggy9/HKHacking