If it were not for the fans, which is really a disgrace and one wonders whether only citizens working at RaidSonic both the development office and in quality control with Höhrschaden. As you can release a system with such a noise on the consumer, a mystery to me, especially quiet fans really will not cost a fortune indeed. Even the positioning of the device under the table does not bring any real improvement, the sound is clearly audible and annoying absolutely on time.
One can only return or for halfway gifted tinkerer, replacing the fans. In relatively cool HDD's in my case 2x2TB WD Caviar GreenPower is provides with 11dB very silent Noiseblocker Black Silent (s = Computers & qid = 1291749570 & sr = 8-1) with a slightly lower airflow than the original part, but with adapter on the 2- Pin connection.
For something warmer HDD's is an alternative of the Scythe Kaze Mini 40 mm silent fan () with the same air flow rate as the original, but with 14 dB, but by lengths quieter than the original.
Due to the fan problem there for a ansich round super successful, low-cost backup solution only 3 stars, here RaidSonic should quickly rectify.
MfG