Hi , and thanks for your post and question - it's a good one! Generally speaking we do not make recommendations concerning commercial medical equipment. I am hopeful that others will chime in when they see your question and share their own experiences using 'quiet' oxygen concentrators in the home setting.
In the meantime, I was able to do a basic search of the internet and found some information that addresses your concerns. I will say that what is noisy for one patient, may not be so for another. To remain objective, you may want to look for the sound level of the machine, usually reported in decibels, which will give a more practical assessment of the intensity of the sound generated by the concentrator.
For your convenience, here is a link to the search i was able to do: https://www.google.com/search?q=quiet+oxygen+concentrator+at+2+lpm
I do hope you find this information is helpful for you.
All the best,
Leon L (author/moderator)