This audio clip captures the type of sound: https://clyp.it/ltzgugcu
~260 posts and 2 years in, nobody has a clue what it is and WD won't explain it either. The common factors seem to be running them in a software RAID on home servers. It's weird and it's quite irritating, so does anyone on HN have any ideas?
I bought Gold drives so I wasn't expecting silence, but this seems to be prevalent across the Red Pro and Red range too.