Do those 12v-7V fan adapters really work?

[Elvis2]

i run liquid cooling for my cpu but still have 5 80mm case fans installed and they're pretty loud. i'm used to it but it's still kind of irritating. i'm sure i could get by if they weren't running so fast. has anyone tried these?
tia

 

[lobadobadingdong]

You don't have to purchase an adapter, it take all of 2-3 minutes to make your own out of molex Y adapter, and yes they work fairly well at lowering the noise, just keep in mind they slow down your fans, and in return lower the amount of air moved.