Why was the earplugs + bone-conducing headphones bad for tinnitus? Sounds like a good combination on paper - block out external noises with the plugs and play white noise on headphones to cover tinnitus. I currently use noise-cancelling phones for that, but of course the earplugs will do better for noise cancelling.
This is just conjecture, but I think tinnitus is caused by vibration of the inner ear that doesn't come from the eardrum. The inner ear is designed to be resonant for audio frequencies, and the earplugs contain them, maybe too much. Just N=1 longitudinal study involving an early stage career and now way too much podcast listening. Covering tinnitus doesn't make it better. Covering the 'noise' is futile. The best you can do is try not to make it worse. You'll never get relief. But you can achieve surrender.
I have been (just barely) covering my tinnitus for the past ~9 years and I'm better off for it. The sound that I replace it is much less annoying than the tinnitus sound. I believe Tinnitus Retraining Therapy is about doing something like that.
What I’m saying is that bone conduction, including tight seals of earbuds, or even use of earplugs in certain environments (roadies etc), might actually be far worse than the sound coming into the ear canal by air conduction. This seems to be my experience.
