I have a RS small Optimus speaker (stereo pair). It operates on four AA batteries. I plugged the powered speaker into my CC Crane radio's headphone jack, and it easily played the music at various volumes. I then took it to an elder neighbor's house to attach it to his TV. He's hard of hearing, and the plan is to put the speaker close to where he sits. That way he doesn't have to boom the TV sound when others are present.
He has a Sharper Image (now defunct store) device that plugs into the audio RCA jacks of his TV. The remote headphones are placed in the device's box to recharge the batteries in them. The set up works, but he manages to leave the headphones off it and often forgets to turn the power off. That drains the headphone power. He often puts the headphones in the cradle the wrong way, and they don't get charged up.
The speakers should be the answer, but when I plugged them into the RCA audio cable from the TV, single plug into the speaker, nothing happens. That male audio plug looks identical to the one I used with the radio. What's wrong here?