No. While using the Arc, there is no method of using a third party subwoofer for the TV input.

To use a third party subwoofer in a home theater context, you must use an Amp driving your own pair of front speakers, with the faux center channel. That’s the only situation in which the subwoofer output is active. When driving surround speakers with an Amp, the subwoofer output is turned off. 

Thanks Bruce

Disappointing though. So, the only way to add bass to my current setup is to get a sonos subwoofer?

Already spent so much for the arc and One SLs and even if I can get the money ($1240 in SA, by the way) for a sub, there is no stock in SA. That is why I thought of a workaround: buy a second hand connect amp and 3rd party active sub. 

For use with an Arc, yes, you would be restricted to the Sonos Sub. 

Stock for many electronic devices throughout the world is restricted, due to both the chip shortage, as well as the pandemic’s effect on shipping.

Sorry to be the bearer of bad news. 

How about a Beam in place of the Arc, will it work?

Thanks, I give up.

Just to clarify, the explained limitation above only applies to TV inputs, yes? It should work for Music, streaming services, right?

Which limitation? Most of what was explained above was hardware related. Whether you’re playing Music, or the TV input, there’s still no port to send out a subwoofer signal on the Arc. When using a Sonos Amp for the front speakers, the subwoofer output is on, when the Amp is in use driving surround speakers, the subwoofer output is turned off.  Doesn’t make any difference what input you’re playing. 

I got a similar question. If use Arc as front speaker, two Sonos One as surround. Can the third party sub work by connecting it to Sonos Amp? (mean the Sonos Amp only use for sub) Can Arc send sub signal to Amp? So far what I know is when the Amp use for surround, the sub port will get disabled. I asked a Sonos sales person in my area, they said theArc will not work with any 3rd party sub, is that true?

No, not really. 
 

You could connect the third party sub to a separate Sonos Amp, and the ‘group’ that Amp with the Arc, but then you’d have that minimum delay of 75ms between the two rooms. It would be unpleasant.