Pairing Play:5 (gen1) and Sonos One

That's because you can only pair speakers the same number and generation (Except the Play One where you can pair the Gen 1 and Gen 2). Speakers of a different number have different music dynamics that would not work well for stereo imaging.

So you can pair Two Play 5's Gen 1 or Two Sonos Ones (G1 or 2). But not a One with a Play 5.

So your best bet is to buy another Play One or an Old Gen 1 Play 5.

Before I bought it, I asked this question and I was told that I will be able to pair it
it's a shame for Sonos.

No, it is a shame the salesman does not know his products, there's a valid reason they are not pairable.

You can still group the speakers to play in sync. That works regardless of speaker and generation. 🙂

Hi Avner

Hopefully, this will explain things better. The analogy is simple but other factors can be brought to bare as well.

The Play 5 regardless of generation was a much more advanced speaker in terms of internal components than Play 1, Play 3, Sonos One and Sonos One SL.

If you were buying analog (wired speakers) they are sold in matching pairs even if the brand has multiple models. A speaker containing one Mid-range and two tweeters is not matched with a speaker that has a Mid-range and only one tweeter. The resulting sound of the two would not create a balanced stereo soundstage.

So as was said by @bockersjv...don't blame Sonos...blame the inadequate sales person who only wanted to make a sale with no regard for you the customer.