I think I’ve just gotten used to having the hearing protection on. I even noticed the other day I still had them one while hand sanding a project I want to get a nice set of hearing protection with bluetooth so I can listen to music. I’m used to wearing headphones at work a lot to drown out noisy cubicles, so maybe that helps too.
I will say that a quick cut on the miter saw and I won’t put the hearing protection on either.
Another thing I’ve noticed is it’s quieter in the shop when I have all the doors open. It gives the noise some place to go. You could try building a false-wall around your dust collector. That would force the noise up into the ceiling. If you got some stick-on carpet flooring tiles and put them on the ceiling above the dust collector, it could help deaden the sound.
I’ve done some speaker design and home theater work in the past and am always looking to ways to kill sounds. I started dealing with tinnitus when I was in my early 30’s due to dumb decisions in my earlier days regarding noise. (Harley’s, open exhaust on boats, large speakers in small truck cabs)
I’ll keep this updated if I start making progress again.