You already know you can change Siri's voice on your iPhone, iPad, or Mac. So it stands to reason that you can make Siri sound different on HomePod, too. You have similar voice options on HomePod, but you find the settings in a different place.
If you want to give Siri on HomePod a man's voice or a British accent, here's what you do:
1. Open the Home app and look for your HomePod in the Favorite Accessories list.
2. Long-press (or 3D touch) on the HomePod you wish you change.