Arc Ultra set up with 2 Era 100 as Surround - add Sub Mini?

What is a second gen Arc Ultra? I’ve never heard of one.

With an Arc Ultra, I’d likely add a Sub Gen 4, rather than a Sub Mini, but it’s hard to go wrong with either. You just can’t add a second Sub if you go with a Sub Mini, where as the Sub Gen 4 is more robust, and you can add a second if or when you desire. 

What is a second gen Arc Ultra? I’ve never heard of one. - I mean Arc Ultra 2ng Generation Version

My room is only 140 square feet.

My questuon is : Will music have better sound quality with the Sub mini?

Hi,

please advise how is your music experience with the sub and without the sub.

Get a Sub 4 if you’ve an Arc Ultra and Eras. Yes, the Sub mini will make a difference, but if you want to make the right difference, get the Sub 4.
 

(Not sure the Arc Ultra is on its second generation yet.)

As I’ve said, I’ve never heard of an ‘Arc Ultra 2ng Generation Version’  As far as I’m aware, there’s only one generation of the Arc Ult​ra, as @Rhonny wrote. 

I don’t listen to music through my Arcs, and I don’t have any Arc Ultras. I listen to music through my other Sonos devices. The Arc (and Arc Ultra were designed to be a connected to TV device. While they’re good at audio reproduction, I’d would be frustrated by the width of the soundstage for music reproduction, and bemoan the fact that I can’t separate the right and left further, which is why I use PLAY:5 gen 2s, Ones, and even PLAY:1s and PLAY:3s for music, and reserve my Arcs (with Subs) for TV audio), mostly movies. 

Clearly OP means second generation of the Arc, which is the Ultra. And yes, OP, a sub will make a world of difference. In a space of that size, a Mini will be plenty. My space is 176sq ft and a single Mini can easily overpower the room. I tested with both a Mini and full-size Sub and actually prefer the punchier tighter bass of the Mini. And you can add a second Mini if you use a 2nd party app called Sonosequencr. That said, with correct placement, you likely wouldn’t need to in a space that size.

Hi Jesterlz 

Please advise the world of difference is, 

How the music becomes good and movies music listening experience 

Currently your Arc Ultra is responsible for creating the low end frequencies of music and movies. With a Sub, it hands across responsibility for the low frequencies to the Sub (or Sub Mini) to handle those, which the Sub is much better designed to do. And you will get incredible bass that you can feel - much more cinematic - and which doesn’t appear to have a point of origin unlike (to a degree) when the bass comes from the Arc Ultra. With the Arc Ultra then not needing to worry about the low end, it can concentrate all it’s power on the mids and high ends, giving a much clearer sound across these frequencies, including speech. 

Well, it’s a subwoofer; so naturally, it adds deeper bass. As importantly, because properly generated bass wavelengths are very long, it creates an effect known as bass omnidirectionality where the perception of where the bass sound is coming from is detached from the source and decentralized (the bass sounds like it’s originating all around you). And it allows you to potentially reduce the bass setting applied to the other components, enabling a cleaner crisper sound, with the sub handling the lower-end frequencies. Addition of a sub enables more realistic recreation of the intended sound, whether music or movies, and does so in a way the smaller lower-powered speakers in the other components cannot.