Even slightly is a stretch, those things are vicious 4000 rpm fans [1.6A], I've got 6 of them on a HashCoins Ares and combined they're the loudest fans I've had on a mainstream miner.
Yeah, I don't expect them to be quiet, per se. I just know several people on the forums have said these measure in around 50 db versus the 70+ that has been measured by some with the stock S5 fan. I'll do a side-by-side comparison when they come in and update. Even if they don't improve things, still good fans to have on hand and @ $20/pair, hard to turn down.