I started mine up today and it was like you had turned on a vacuum cleaner- heck, even my vacuum cleaner is quieter. I had to put it in the basement and powerline it in the end, but are these units supposed to be so loud? I had a hard time even being in the same room as the miner. At first I thought it was my PSU making the sound but I noticed a few seconds after I plugged in the power to the PSU the noise would take over, and air was running through the miner.
It's really not an issue for me as I can plop it in the garage or basement and it'll get much much more quiet, but it's just a tad bit annoying.
Upgrade the fan with a Twister Storm ->
http://www.enermax.co.uk/fans/twisterstorm/It will need an external power supply, but, your SP20E will sound no more than an average tower and will still hash @ 1.4Th/s!