Apple introduced the HomePod mini six years ago, in 2020.
I'm not one into smart speakers, but the feature that made me take a closer look was their ability to form stereo pairs, without any direct wired connection.
I know there are other speaker manufacturers with wireless speakers, but to my knowledge, Apple was just using AirPlay over WiFi... so how does it work?
Through the magic of buying two HomePods mini (pictured above), I found out. A video detailing the process is embedded below:

Jeff Geerling is a software developer, author, and open-source contributor known for his expertise in infrastructure automation and Drupal development. Readers can learn about DevOps practices, Ansible automation, and web development with Drupal. With blog posts, tutorials, and open-source projects, Jeff Geerling shares  insights and best practices for building and managing web infrastructure.

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A deep dive into how Apple HomePod mini achieves wireless stereo pairing using Precision Time Protocol (PTP). By sniffing WiFi traffic with macOS Wireless Diagnostics and Wireshark, the author discovers Apple uses gPTP (IEEE 802.1AS) and Audio Video Bridging (AVB) standards over Apple Wireless Direct Link (AWDL) to synchronize audio clocks across multiple speakers to within a microsecond. The post also covers setup quirks (HomePods require an iPhone, not a Mac), and explores Linux AirPlay 2 compatibility options like owntone-server and airplay2-rs.

HomePod mini feels like magic, but it's just good timing

Setting up a HomePod mini (no Macs allowed)

Searching for PTP over WiFi with Wireshark