My home network contains, among other things, a NAS device.
This is a device that you would run 24x7 for general availability right ?
However I prefer to keep this device in the living room, because that's where the 1Gb ethernet switch is located.
After a couple of months the noises that the device produces became too loud and annoying, so time to call in the help of Tinkerboy.
Step 1: Find the noisy component.
Upon opening the case (oops there goes the warranty) I did a swift aural inspection with the NAS running.
In fact the noises had two sources:
-the vibration from the hard drive
-a cheap small fan running at full speed.
Step 2: What to do about the fan?
Next the fan: how to reduce its noise?
I could think of the following options :
-replace with quieter model
-reduce fan speed.
I opted for the second, knowing that the spare small fans I had were equally noisy.
The preferred option would have been to get a smart speed control, but this would have to be completely self-supporting and a design was not readily at hand.
So eventually I opted for the simplest: reduce the fan speed by adding a resistor.
This reduces overall airflow so introduces the risk of overheating. But the NAS webpages show the temperature of the disk, so I decided I could monitor if cooling is sufficient using that information.
Step 3: Deciding on the right resistor.
I hookd the fan up with a 12 powersupply and added some resistors to find the best result as far as noise and reasonable fanspeed were concerned.
I found a 56 ohms resistor (green-blue-black-gold) giving sufficient speed reduction to get rid of the whining noise while maintaining a reasonable fan-speed.
I also took a small piece of white insulation to fit tightly over the resistor, so none of the bare metal can cause any problems.