Help! Noise!

[DoctorBooze]

I'm putting this system together. Looks like 8 fans, 4x 40mm and 3x 80mm all on the case, and 1x 60mm on the HSF. Looking at them on 2cooltek.com, and picking the quietest going, if I got my sums right the machine's going to be making 51dba of noise.

First up, does anyone know what 51dba sounds like?

Second, what do I do to the case to soak up some of this noise on the inside? I'll probably need to stop the case reverberating as well but that's covered in another thread.

Help!

Cheers,

John.

 

[titanone31]

51 dbs is pretty loud
go with larger and lower rpm fans
should lower you noise level
i have 6 80 cfm 120mm fans and
2 60mm 27cfm ys tech fans in my case
and the 2 ys tech are louder than the
six 120's are.
i have the 80 cfm 120 for sale for 9.00+shipping
can be seen at http://communities.msn.com/Titanone31s

 

[lifeguard1999]

It would be interesting to see how you did your sums to come up with 51 dBA.

 

[DoctorBooze]

Lifeguard, I'm not sure if it'd be all that interesting, because I did them wrong
I used natural logarithms instead of base 10. Having now recalculated, the correct figure for the fans I'd picked was in fact 41db. Anyway, since I've done a bit more research, and taken the excellent advice of another Anandtech forums regular, I've got a new solution with just the 5 fans, three of which are variable flow depending on the ambient temperature. At cool temperatures (inside the case below 30C) I'll have 41CFM intake plus 41CFM exhaust, together with the 26CFM into the heatsink and 20CFM out of the PSU, all at 27db. At full tilt, if the ambient temperature were to reach 50C, I'll have 82CFM intake and 70CFM exhaust, plus same heatsink and PSU, all for just 39db.

Unfortunately it now looks like the hard drives will be the noise problem. The IBM hard drives produce 31db of noise each, and they claim they're the quietest in the world. But with 4 drives, my system will usually be making 37.5db of noise. Damn. Oh well it's only a little quieter than a FOP-38

Yup, a happy end after all.

Cheers,

John.