Inside a small server room - 5 devices. The sound pressure level is too high. My suggestions for noise reduction: 1. The increase in floor space of input and output channels. 2.Install blowers at the lowest possible speed. 3. Do not install the fan in tandem. 4. Apply a cooler with a large distance between the vertical plates. 5. Dismiss from work of developers. To ensure that users not obsessed. :)
You might try loading the FRUSDR files so that the fan speed control is functional and / or turning up the air conditioner.