So I have heard that the Be Quiet series (their case fans more than others) operate at a very high/low frequency, outside the range of human hearing. It keeps them silent, at least to us, but has some risks. A very low frequency will hurt the hearing and make you lose your hearing faster and damage it. A very high frequency will irritate the brain, make you feel frustrated or sad, and may cause some damage. I can’t find any other information on this issue, but there is evidence. I’m a little paranoid now, is it just the be quiet series? Do my fans do that? I was thinking on getting new case fans and was looking into the be quiet series when I cam across this. Other than that I was thinking about getting Noctua fans, are they safe? Like I said, I can’t find a lot of information on this, could someone put my paranoia to ease, and/or warn me on any other fans? Thanks.