I’ve never seen any generated by Sonos, no. I think there may have been others who have published such a thing, but you may want to Google that. 

Since the 300s have not yet been released, none of us really know if the Sub would do for you what you want. We’ll need them to be out there in order to do some testing. 

My recommendation, if you’re not interested in spatial audio from the limited sources that are out there, go with the Sonos Fives. And you can try out a Sub, mini or not, by utilizing Sonos’ return policy. 

Hi

Frequency response or not IMO (and supported by Sonos marketing here at the end of the page) the Era 300 will not provide the pure stereo imaging you get with your Play 5 (Gen2). I dare say the Era 100’s may  be a better choice for pure stereo imaging vs the Era 300’s; especially bonded with a sub. 

the Era 300 will not provide the pure stereo imaging you get with your Play 5 (Gen2).

So frequency response is important to me, but you do raise a good point and its one thing I’m struggling to understand:

• 1 Era 300 playing Atmos Stream = Spatial Audio
• 2x Era 300 in a “Stereo Pair” (what they call it in the manual) playing Atmos = Spatial Audio of some sort, but unclear how the audio gets mapped.
• 2x Era 300 in a “Stereo Pair” playing non-Atmos = ? Is it going to sound like stereo or is it going to sound more mono? 

I’m guessing that won’t be clear until they are in the wild. 

The only reliable way to decide is by listening at home in the target space with well chosen tracks. 

Frequency response charts, even for standard stereo music, can only guide as to what speakers to test by narrowing things down to a few speaker models. I doubt these charts even exist for things like spatial audio.

That's true, I like spatial - the piece I was trying to figure out though was I there was still a frequency gap from the Five to the Era 300+Sub/Sub Mini. I listen to a wide variety of music and I didn’t want to waste my time with the Era + Sub if it was going to have a similar gap as the Five compared to the HomePod.

To be clear - are you saying you perceive a gap in the music frequencies when playing stereo music on a 5 bonded to a Sub? 

I have a play 1 + Sub set up and find none such. I don’t recall any such issue here in any post when the 5 is played bonded to a Sub.

I’m trying to figure out if bonding an Era 300 to a sub will fill in missing frequencies that the Era 300 has (according to some of the early reviewers like Peter Pee) in comparison to the Five without a sub. 

My is it will, mostly, but I hate to order the goods and then return them because they don’t.

With the caveat that no one has really heard the Era, and that my experience is limited to play 1 + Sub, for stereo music I see no reason why 300+Sub should not do a better job of playing stereo music compared to a 5 without the Sub. Either alone or as a stereo paired set up.

That was kind of my thought process. Which Sub is the question, is the Mini enough or do you think it needs to be the full Sub Gen 3?

Again, I have never heard the Mini, but an educated guess is that in a typical modern room of up to average size, the Mini should be quite sufficient. If the Era 300 are enough, so should the Mini Sub be, I would expect.

Honestly I wish the Gen 3 was available in a Matte finish

Where music play is concerned, the classic definition of a good sub still holds: one should not realise it is playing when it is, but it should be missed if it isn’t. A corollary is that it need not be seen as well, so the finish should not matter! Mine is covered by a dust cover that is transparent to sound, so again, the finish is not relevant.