Which do you have?
an HDMI cable and a subwoofer
an RCA cable and a subwoofer
Just an HDMI cable
Just an RCA cable
Year, Make, and Model RV
It is easy to understand all the confusion, I was having while trying to figure out the wiring, what channel "C" switch actually does, and whether I had a subwoofer.
It is also a reason why anyone who is seeking advice about their RV needs to provide a year, make, and model number. Forest River makes three class "C" motor homes that are basically the same, except for how they are accessorized. The Forester, Sunseeker, and the Dynamax Isata. All three use the sprinter chassis, have basically the same cabin layouts but are accessorized differently.
For the Newbies, make yourself a signature. Click on the "User CP" Include a year, make, and model number for your RV...this way everyone will know whether they are talking apples to apples instead of apples to oranges.
If you need help with an appliance, provide the manufacturer and the make of that appliance, without that information all you will get is general trouble shooting information, instead of specific information on your appliance.
BTW, I have the HDMI cable and no subwoofer. The sound does automatically go to the JWM6A from the TV, if the Stereo is set on ARC, but the volume is SO LOW, that you need to turn both the TV and Stereo volume to 25+ or you can barely hear the tv output through the stereo speakers. BEWARE, if you turn the volume up so you can hear the TV output, TURN IT DOWN before making the sound source the JWM6A or you may wake up the dead,