What model TV are you using with the Arc? Have you tested the Arc with a 5.1 or Dolby Atmos audio source? Have you performed Trueplay?

Only after spending two hours reading forums did i come to realize that you cannot add satellites to an arc and worse yet that my era 300s as rears are actually better on their own but you cannot switch back and forth between listening to era 300s on their own vs as rears as you’d have to ungroup and re group every time and then true play. So as it would seem I have good sounding rears that I can’t listen to in their best output. 

Adding additional Sonos speakers to a TV setup (Grouping) usually sounds so bad from the delay/echo effect no amount of sonic improvement is worth it.

If you want a LOT of sound up front you could put an Amp on your TV and use some large and loud conventional speakers. It would still connect to and use your existing surrounds.

The Amp really doesn’t care what it is connected to, all that matters is the impedance (Ohms) it sees between the speaker wires. Usually 8 but it will work with 4, less if you get the Sonos/Sonance speakers when it will power three on each channel.

​@Stanley_4  so you’re saying I could get some BW front surrounds and run those vis wire into my Sonos amp in my basement and then just create a new group of those plus my arc and 300s?  The amp has to work with wire right, not wireless?  If this is what you mean problem is you never know how non soundbar speakers from a different company will sound with the arc. The arc is really 2 surrounds and 1 center in a single speaker. It essentially has the front surrounds built in so adding more might make it sound worse since you’re adding on top of something that wasn’t designed for it 

You could, what I was trying to make clear is that it would sound like a short word the forum will likely filter out.

The Amp doesn’t care what label is on the speakers, only the impedance so you can use any speaker or combination that is within the Amp’s ratings. The Amp has to be wired to power and the speakers, Ethernet is optional and not usually recommended.

Adding more speakers won’t make the sound worse as such. It will absolutely do two things, both bad. It will reduce the stereo imaging, muddying the sound stage, but far worse for most people is the delay I mentioned, the echo effect completely ruins the sound for most people.

If the new speakers have a frequency response that is far from the Sonos you’ll get additional audio artifacts that will likely also worsen the experience but that has to be tested in-place, one set of speakers at a time, there is no generic answer.

This is pretty much the same answer folks have been getting to your question since the first Sonos home theater system. One front Sonos, two Surrounds, none, one or two Subs. Nothing else is going to work well or be supported.