I am working on a design to reduce noise caused by the computer's power supply and case fans which are amplified via the metal case.
The cases are as you see in the picture above. They are standard 19" 4U computer cases with a front intake behind the door on the left and power supply exhaust in the rear as typical.
What is prompting me to consider this project is that the fan induced noise is about -30dB on my peakmeter. A pair of 3/4" laminated boards sitting directly in front of the fan only reduces noise at best by -5 dB.
The greater noise is generated through the power supply exhaust fan. bouncing off the wall behind the desk upon which the case sits on.
The graphic drawing, above omits the planned front door which would have a foam panel of some sort on the inside and perhaps a magnetic strip as used on a refridgerator door. Some early tests on an actual refridgerator had demonstrated a dramatic noise reduction - my guess is something to the tune of as much as 40-50 dB reduction. but that's only a guess. (Wish I had dB/Freq meter)
This initial drawing attempts to illustrate the Bank Vault stepped-panel-like design
You will notice between the inner and outer box a 1.5" polyethelene foam gasket.
Initial thoughts were to incorporate solid foam panels that run the depth of the chassis, however, I am suspecting this "might" not be necessary and airspace or a different product may improve on the isolation.
The door would be removeable for convenience' sake. Only time the door would actually be needed is when recording in the same room.
Ventilation is achieved by means of ducted air which travels from the rear of the cabinet to the front between the upper and lower computer cases. (What appears to be blank plate is open space) Auxillary cabinet fans and ducting to be ironed out. I am visualizing an intake and exhaust port which are exceptionally large with some sort of "muffler" like design incorporated in.
I've been researching ways to quiet down the computer, the source of the noise with
some ideas coming to mind from inspiration of studio and industrial soundproofing and acoustics treatment. But boy that's an awful lot of reading and disciphering.
It would seem to me that I might be better off using less surface contact than to use inner box size foam panels as the substrate for the case cabinet (inner box).
Ie less foot print = less mechanical vibration transfer.
Would anyone in the know have any ideas or suggestions??