My fight against resonance from HDDs in a NAS

[Spindel]

Sorry mods if this is the wrong section, but I thought the following post is applicable to any case of equipment that produce vibrations and thus I put it in general section of the forum. 

 

So I have a small consumer grade home NAS for my main file storage (Synology DS416). I have 4 HDDs in it (2x4TB WD Red and 2x8TB WD Red). 

 

I live in a wooden house and have been annoyed by resonance frequencies from the HDDs that caused a clearly audible hum. So finally I decided to put my engineering skills to it and since the solution is quiet simple I decided to share if anyone else want to "fix" this issue. 

 

First the basics of resonance from vibrating machinery: What most do wrong is they only try to put vibration absorbers on the machine (in my case my NAS) then place it somewhere, with a small improvement but still with a lot of resonance. What you need to do aside from putting vibration absorbers on the vibrating machine is to also place the machine on something with a lot of mass that is dense, so not wood (since wood contains a lot of air and acts as a resonance box), and then you put vibration absorbers on this mass to before placing it on the material you do not want resonance frequencies from (in my case my wooden house and any bookshelfs/desks in the house. 

 

My Synology comes with 4 hard rubber feet that are useless at absorbing vibration so first fix was to put som felt stickers (in my case from IKEA) on it. I stacked 3 on top of each other to give it some hight since they will compress some and I do not want the rubber feet to touch anything since they will carry the vibrations.

      

 

For a mass I had at hand an half concrete pavement stone, I put felt stickers (also from IKEA) on this to isolate it. I stacked 2 on each again to deal with them compressing a bit. I also put in 5 spots, but 4 would probably suffice as long as it is stable. 

 

And lastly I placed the NAS in its place (don't worry there are holes in the back so there are no air flow problems)

 

I used what I had at hand, a thick metal plate more cut to size would work, the important part is to have a lot of mass (in relation to the thing you want to prevent resonance from) that you put your vibrating machinery on.

 

This won't make it completely silent since as long as you have moving parts and fans there will be some noise. But now my NAS in inaudible unless I put my head next to it. Before this "fix" you heard the "hum" from several meters away (and depending on placement in other rooms since resonance vibration travel). 

 

So the TL;DR steps:

1. Vibrations absorbers on the thing that gives you resonance
2. A large mass (in relation to the vibrating mass)
3. Vibration absorbers on the large mass
4. Place large mass where machine will go
5. Place machine on the large mass
6. Enjoy (relative) silence

 

[Skiiwee29]

<-- Moved to Guides and Tutorials -->

 

This is a good guide on how to reduce noise. Great share. Thanks! 

[Haraikomono]

hats off for ingenuity

but angry smiley for using synology

 

[StDragon]

For high frequency resonance dampening, look into Dynamat