Recently I was asked techniques for soundproofing a server room to keep the noise down in a small to medium-sized office. Before the discussion dives into the article, there are a few things to keep in mind
1. Don’t let the soundproofing aspect overtake the airflow aspect. Airflow is critical.
2. Make sure your solution meets fire and building codes.
3. Mass always wins when it comes to soundproofing.
Now on to some ideas.
Acoustic Foam
https://www.thefoamfactory.com/acousticfoam/acousticfoam.html
Ceiling Tiles
Ceiling tiles are typically sound absorbent, but you can get some with higher absorption than others.
Soundproofing on the cabinet
For those of you familiar with high-end car stereos know products like Dynamat and other sound deading materials. The work in two ways. The first is by adding mass to what the are applied to. Secondly, they are made of materials specially designed to absorb sound. There are many kinds of these on the market. One such product is here on Amazon
Other techniques
Keeping the air conditioner on a decent setting can cause the fans in the equipment not to work as hard. If the device is getting cooled the fans may not have to spin at higher RPMs to move air. Proper airflow through your cabinets and racks helps greatly with this. If you have your equipment taking cold air in from the front, where maybe a vent is in front of the cabinet door, this can greatly help.
Supplementing your cooling with a slow moving large fan. Large fans spinning at low RPMs can move just as much air as smaller fans spinning at higher RPMs. If your server room needs help this could be an option.
Proper cable management is also essential for airflow. The better the air moves through the equipment the cooler the equipment will be. As stated above, cooler equipment means fans are not spinning at high RPMs generating noise.