Anyway so I got these two fans in there now, on in the front and one in the back, and my temps are about 15C lower under load, which is great. Except now my computer sounds like a freaking vacuum and I can hear it from the living room. Well, it WAS the world's quietest case... I plugged both fans into the full power plug (maybe this isn't neccessary?), and the store didn't have any of the Antec fans, which I don't know if those run quieter or not but yeah...
I love my Sonata case.
But it sounds like you just picked up two 120mm fans at random. I'm sure that there are quieter fans out there. Here's my current list of 'quiet' 120mm fans.
<pre>SilenX 120mm 11dBa 40CFM <font color=red><< cheats with rubber gromets to get low dBa</font color=red>
SilenX 120mm 14dBa 58CFM <font color=red><< cheats with rubber gromets to get low dBa</font color=red>
Thermaltake A2018 120mm 17-46.5dBa 38.6-93.7CFM <font color=blue><< speed adjustable</font color=blue>
Papst 4412 F/2GLL 120mm 18dBa 41.1CFM
Akasa AK-183-L2B 120mm 18dBa 44.8CFM
SilentMaxx SF120/12 120mm 19dBa 41.2CFM
Cooler Master SUF-S12 120mm 22dBa 42.73CFM
Nexus D12SL-12 120mm 22.8dBa 36.87CFM
Enermax UC-12FAB 120mm 24.6-43.6dBa 63.05-94.92CFM <font color=blue><< speed adjustable</font color=blue>
Mechatronics G1225S12B 120mm 25dba 55CFM
Papst 4412 FGL 120mm 26dBa 55.3CFM
SilentMaxx SF120/16 120mm 26dBa 55.3CFM
Silverstone S35-1000 120mm 27dBa 54.5CFM
Powmax P456-6003 120mm 27dBa 54.5CFM
Vantec Stealth SF12025L 120mm 28dBa 53CFM
Panaflo FBA12G12L1A 120mm 30dBa 68.9CFM
Thermaltake Thunderblade 120mm 21dBa 78CFM <font color=red><< reviews say dBa is 30</font color=red>
AcoustiFan AF120C 120mm 34dBa 66.7CFM
</pre><p>I'm contemplating getting two SilenX 120mm 14dBa 58CFM fans for my Sonata. They come with silicone screw replacements much like the Sonata comes with. Those do seem to reduce fan noise.
But since you have a Sonata case, you can hook your fans into the fan only plugs and this should help reduce the fan noise. That's what they're there for.
If it doesn't work out you can always move them back onto noisy full power.
<pre><b><font color=red>"Build a man a fire and he's warm for the rest of the evening.
Set a man on fire and he's warm for the rest of his life." - Steve Taylor</font color=red></b></pre><p>