Connecting Wireless Headphones to Sonos

Connect the transmitter to the Port via RCA.  That should work.

Did that.  Powered up the transmitter, connected my speakers and tried to stream some music but no sound?  Any further suggestions?

I should clarify.  I have my turntable connected to the In Port and connected the Bluetooth transmitter to the Out Port.  

Set the Volume Level on the Port to Fixed.  It may be a case of dueling volumes causing the level to be low. 

How do i do that?  I assume using the app in settings?

They now call it “Line-Out Levels” (don’t recall when that changed).

Open the Sonos app for iOS or Android.

• From the  Settings tab, tap System.
• Select the room with your Port or Connect.
• Tap Line-Out Levels and choose one of the options.

Thank you!  I’ll give it a shot when i get home.

I’m not sure I’d recommend using Fixed Volume on the analog outs into Avantree Oasis Plus. There’s a chance of overmodulation/clipping. 

Since that transmitter has an optical input you could get an inexpensive coax/optical converter and simply run digital all the way, instead of DA conversion in the Port then AD conversion back again in the Oasis Plus. 

Has anyone determined if it is possible to connect wireless headphones to a Sonos system, via the Sonos Port or any other way?  I too would like to connect Bluetooth wireless headphones to my Sonos System and independently control the headphones’ volume, etc.

The only Sonos device with an analog output is the Sonos Port, you would want to connect the Bluetooth transmitter to that analog out, and send the signal to your headphones.
 

There is no other way to connect headphones directly to Sonos, although some folks have connected their headphones to the digital output (optical) on their TV sets, changed that digital output to an analog one, and then sent that to their headphones. It has the benefit of not getting involved with CEC via HDMI, and ‘blocking’ some other audio sink. This is a pretty good solution for TV watching, not so great for just music.