Isn’t there any RCA output on the Sonos Amp that is labeled SUB?

As near as I can tell, the OSD Forza 10 is a passive Sub, and the Sonos is providing a line level output. You’d need either an amplifier to power that Sub (evidenced by their own copy ‘For the best performance, pair it with our recommended subwoofer amplifier & let the immersive outdoor audio experience begin.), or an ‘active’ (self powered) Sub to use with the Sonos. 

Sorry, I jumped the gun. Where do you have your Y connector hooked up on the Sonos Amp? I would have thought you just need an RCA style cable from the Sonos Amp’s output to the line level input on your Nobsound. I guess I need to go look that device up.

Airgetlam, the Nob amp has a Dual (red/white) input. So I put the single RCA on the Sonos Amp out, and the 2 RCA’s on the Nob input side. 

Thank you for the assistance. 

Eliminate the “silly”. Check that the subwoofer amplifier is connected to AMP’s ‘SUB’ output.

And double check that Y adapter, to make sure it’s Omni directional. In fact, I’d just oull it out of the loop completely while testing.

Any RCA-RCA cable could be used, it does not to be an RCA-Y.

I don’t recommend a SONOS SUB in this application.

Another “silly” is a wiring fault to the passive subwoofer. You can check the wiring by connecting a flashlight cell to the speaker wires that normally connect to the Nobsound G2 PRO amplifier. At the instant of connection, the subwoofer will thump.

Thanks Airgetlam and Buzz for the responses. I have pulled the Y out and tested with just a red to red or white to white RCA to either of the inputs(red or white side) on the Nobsound G2, did not change anything. Again, Once I plug in the RCA, The Sonos does give me the Sub menu and I have enabled it and turned all the gains to high just to try anything. Still noting. The  OSD Forza 10 is a passive Sub has 2 wires coming out, Blue and Back, I have connected them to the 2 speaker out’s on the NobSound. Still nothing. frustrating for sure.

Buzz, not real sure what flashlight cell to the speaker wires?

I would ask, if there is an external AMP you absolutely know works, that doesn’t break the bank, please give me the model, I have a wedding shower outside and want that sub working, my 4 5.25’s are ok, just no bass. 

Thanks in Advance.

You know when you feel stupid, but after about 5 different ways to sunday, I went out this morning and tried a diff sub, it worked.  Almost fell over, then I reconnected my OSD outdoor and boom. It worked. Wow.. painful.

Thank you guys for the info.

It always pays to check the “silly”. It’s possible that the speaker connections were oxidized and not making contact. By disconnecting and re-connecting you accidentally cleaned the connections.