Let’s make a list of all the bearing types there are in no specific order.
YYF SPEC
CT
CTX
Terrapin X
Trifecta
OD 8-ball
OD 10-ball
Size A
Mini Flea Bearing
Billybob Bearings
Konkave Bearings
Size D
YYJ HalfSpec
YYJ Speed
GenYo AIGR
Lubed AIGR and 10-ball are quiet. But they don’t hold a candle to NSK bearings. Dry NSK (which is how the manufacturer recommends running them) run about as quiet as a lubed AIGR or OD 10-ball. If you ignore the manufacturer and put the tiniest amount of thin lube, the NSK is inaudible unless you hold the yoyo up right next to your ear.
Agreed, NSK’s are easily the quietest bearings I’ve ever tried. Gold center tracs would be second, the one I have in my Phaser has been in there a fair while now and it’s still remarkably quiet, even without any sort of maintanance.
Regarding flat bearings, I agree with pineapple jumpsuit (now there’s a phrase I never thought I’d say…), I’ve found AIGR’s to be quieter overall than 10-balls.
There’s always that moment with OD 10-balls when they’re all smooth and quiet and then out of absolutely nowhereCCKKKZZZZZZSSHKKKZKSSCZKCZKK!!!