Sound cutting in and out on main house tv box. The other tv boxes work no problem

I've troubleshooted this for ages. Replaced cables, removed audio receiver, replaced HDMI cables, upgraded HDMI cables, tried a different TV. All the same issue on all channels. Sounds intermittently cuts out twice a minute, 3x a minute, once a minute..it doesn't matter. The odd thing is, the mini set up box in the bedroom works just fine. No audio issues, no complaints. Do I need to get a new set top box for my main living room? That's the only component that I can't test since I don't have another.