We always knew that the HomePod would be designed to play particularly well with Apple's other devices, and some digging around in the iOS 11 beta code by iHelp BR confirms it: you are indeed going to need an iOS device on hand to pair with Apple's smart speaker during the initial setup.
Bad luck for those of you who were hoping to just use a MacBook or an Apple TV to do the initial setup - although the HomePod will almost certainly work just fine with these devices after it's been configured for the first time.
That said, this is beta code, so Apple may change the requirements later on. The initial setup seems to be similar to the one for AirPods, which need an iPhone, an iPad, or an iPod Touch to get up and running once you've got them out of the box.
Home sweet HomePod
It looks like two-factor authentication and iCloud Keychain approval are needed to complete the HomePod setup, based on the iOS 11 code, and once that's done the speaker syncs with iCloud and your Apple Music account. Apparently firmware updates will be handled through iOS too.
Finally, the code also suggests you're going to be able to update and change the settings across multiple HomePods, should you be enough of an Apple fan and audio enthusiast to invest in more than one of them.
Apple has been keen to promote the key features of the HomePod, which launches in December and lets you blast your tunes around the house as well as chat to Siri - but it hasn't said much about the finer details of the device, hence all the code digging. It'll cost you $349 in the US, with international pricing yet to be confirmed.