Yes, you’re correct, for Home TV Home Theatre surround sound, you will need another Sonos Play:3 speaker.

The Beam will play the front left/right/center and height TV audio channels and it ‘bonds’ over WiFi to two Play:3’s, which will play the rear left/right TV audio channels. All speakers will output music audio too.

When setup in the Sonos App the Speakers, when bonded, collectively display as one Sonos Room.

This setup is usually done with two similar surround speakers, so you will need another Sonos Play:3 in your case.

Which are hard to come by, the PLAY:3 hasn’t been produced for many years. I’d be looking for one on resale sites such as eBay and similar places. The chances of finding a new in box version is pretty slim. And at the cost, you may find it easier and as cost efficient to purchase two Sonos One SLs, or a pair of equivalent speakers from IKEA.

Hi, Ken. Thanks for you suggestion. I will do that way. But the only thing it’s very hard to buy another Play3, I don’t want to spend $200 to buy an old model second hand one. Do you think can i buy a little bit cheaper Sonos speaker, my budget is around $150. 

Hi, Airgetlam. Yes, i agree with you. Now buy a Play3 is hard and not worth the money. I’m thinking to a entry level version of Sonos speaker, just make it compatible with the surrounding system.

However, i can buy an equivalent speakers from IKEA, but I’m considering if there’s sound quality can be good? I assume the beam Gen 2 is the midrange, the Play 3 is midrange, the equivalent speakers is entry level, they have significant differences sound  quality. Then i make a surrounding, does it matter?

The IKEA's are nice speakers, especially for surroudn duty. Just remember you need two of the same speakers for a surround set up. So two One (SL)'s or two Symfonisks book shelves etc.