"Even white-noise apps make me feel like I'm getting barraged with sound. I want "library quiet.""
The middle ground I have is noise-cancelling headphones (bose qc20) with white noise app playing a low volume mix of grey noise and... maybe brown. The grey gives a low feeling, and helps mask out some frequencies that the noise cancelling headphones miss. It's not perfect, and it's not "library quiet", but I've found the combination is relatively calming most of the time.
The middle ground I have is noise-cancelling headphones (bose qc20) with white noise app playing a low volume mix of grey noise and... maybe brown. The grey gives a low feeling, and helps mask out some frequencies that the noise cancelling headphones miss. It's not perfect, and it's not "library quiet", but I've found the combination is relatively calming most of the time.