How do you play synchronized audio across multiple receivers in 2024?

I have a bunch of Sonos speakers and hooked them all up to a Mac running Airfoil (https://rogueamoeba.com/airfoil/mac/).

It isn't perfect and audio occasionally de-syncs or a speaker drops out. On a dedicated wireless channel playing a local source I imagine it would be pretty solid.

Not really an option if you don't have a Mac to run Airfoil, though if you do you can use the Satellite (https://rogueamoeba.com/airfoil/satellite/) program to sync Mac your other non-Apple devices to the host.

I’ve had success with Snapcast when looking into this previously https://github.com/badaix/snapcast

Are we talking one speaker say left speaker, playing sample 0, duration 0-5s, then right speaker playing second sample duration 5-10? Except increase number of speakers to X with physical locations completely unknown or unaccounted for anywhere in the underlying software itself?

Because last I'd heard, and I'm definitely not in the scene, all of that was coordinated by programs, before having the transduction work parceled out to mostly dumb speakers. And even then, I'm not aware as to whether playback software is "smart" enough to train itself w/ regard to latencies between individual playback nodes to ensure things sync up properly... That gets into the nasty world of things like DRAM signal training, because in a sense, each of your signal paths is just a glorified signal trace to the system in question, of unusual length compared to other motherboard traces.

I know there's ASICs built into most graphics cards nowadays for things like audio mix/encode/decode, but as far as I was aware, getting things relatively sync'd up for any non-trivial network of speakers was still very much an exercise left to the student; and with most programmers having taken the route of "but why would you need that?" to avoid answering what is essentially a really, really, hard network characterization/DSP question.

Long story short, I dunno, but sounds like an immersive literature deep dive in the making to me!

I think Sonos sued the heck out of Google for doing this with Google Home speakers. They won the jury trial but then a judge invalidated their patents https://www.theverge.com/2023/10/10/23910694/sonos-google-pa...

Probably not an easy thing to do to begin with (there are papers on the algorithms involved, last I checked) and the specter of big audio companies coming after you isn't fun either.

Edit: Despite that, there's https://github.com/geekuillaume/soundsync

I've been using Chromecast Audio devices in my house for something like 8 years now and they work perfectly. Some are just the audio device plugged into powered speakers, some are speakers with Chromecast built in. Unfortunately the CC Audios aren't made anymore but I think you can still use regular Chromecasts (possibly with an HDMI audio extractor if needed).

The sync between devices has always been flawless for me.

In the live audio production industry audio over IP with Dante is the industry standard these days.

https://www.getdante.com/products/software-essentials/dante-...

If your rooms are ethernet wired, I just found these USB extenders[0] that I was hoping could eliminate audio latency with bluetooth. I don't know if sync would still be a problem though.

[0] https://www.gefen.com/product/usb-2-0-extender/

Install a low power FM transmitted and use old analog radios as receivers. A friend did this at their island cottage.