Adding TV Adapter for Hearing Aids

The challenge you’ll (or your wife) will experience is a Sonos ‘room’ grouped with your Sonos Arc will experience a slight delay (around 75ms). This may not bother your wife. Sonos devices that provide an output are the Amp and the Port.My choice of those two would be the Port, as you don’t appear to be driving other speakers.

However, if your LG OLED TV has an optical output, and it isn’t being turned off by the CEC system in the TV, I’d connect the adapter to that, so their would be no Sonos delay inherent in the system.

Unfortunately, Sonos doesn’t really offer a lot of solutions for the hard of hearing.

It has been a journey getting to this point. LG (at least mine) doesn't have any other audio available when ARC/eARC is selected. I tried Sonos AMP because it has banana connectors, which could be converted to RCA for the hearing aid adapter. That was a disappointment since AMP would not play sound from the TV, only content from Sonos Radio and other content from Arc Ultra.

I am thinking an audio extractor is the most cost effective solution. However, I found out not all extractors are compatible or capable of passing through high quality ARC/eARC sound AND optical or RCA simultaneously so my wife and I can enjoy TV together. 

I would appreciate, from someone with experience, any recommendations as to which extractors would accomplish the objective. 

If you ‘group’ the room that is the Amp with your Arc Ultra, it should, with a 75ms delay, be playing the same signal, albeit stereo, as the Arc. 

Your challenge is you’re trying to get/set up an ARC/eARC splitter, which is supposed to serve both devices at the same time. I’m not familiar with those, but you’d likely need to get one that is powered, as splitting the signal Is likely, without amplification, to be too low.

But I’ll leave you to others, who will have experience in this. Best of luck. 

Be very careful using the speaker level (banana) outputs for delicate electronics intended for line-level outputs.

Line level is usually under 2 volts maximum while the speaker level ones can put out around 30 volts. 

The Port has line-level outputs as well as optical. The Amp only has a sub li e-level output.