Building an ISO box...

[abyssinianson]

hey all, I am in the process of planning to build a sound isolation box for my PC to make sure the control room is dead silent. Rather than spend for a premade one, I am pretty sure I can build a similar spec'd ISO box for much less. However, I am having trouble hunting for some parts such as the cable pass-thru for the cabinet wiring. I imagine that I won't need anything larger than a 2" diameter pass through but i can't seem to find something that I can readily modify with sound foam or rubber to keep sound from leaking through it. Can anyone recommend a source, preferably a stateside one, that I might purchase stuff like this from? If worse comes to worse, I can always cut up a piece of PVC pipe and ghetto-rig it to act as a pass through but if there are ready made ones that are better made, I'd rather go with specialized parts for that purpose.

I will be drawing up the AutoCAD plans (and posting the blow-by-blow description of the process for you all to check out) for it pretty soon but I need to know the availability of materials before doing so. It looks like I will be building the box out of MDF, insulated by Auralex or some other compatible sound absorbing foam. Also, the design for the air and sound baffles are still in the works because I am seeing a lot of variations online from other designs. I want to work out some kinks in the air exchange calculations and noise that potentially comes along with a given design.

[KitC]

Any updates?

[abyssinianson]

i have drawn up the plans for the thing and currently purchasing the parts for the project. i just put the order in for the fans - a set of nexus 80mm fans, and some sound insulating foam.  right now, I am doing calculations (and research) for the main air baffle design to finally hammer in the dimensions of the box. my only main concern here is I don't know the thickness of the sound insulating foam so i want to get those in before I plot the final measurements.

I am going with 1/2" MDF for the main walls of the box which will be glued together using industrial wood glue. the doors will have locking hinges which I still have to shop for at my local hardware stores.

One part of the design I am still grappling with is the door and how I can design the seal around it. I am thinking of routing the edges and using a combination of rubber and felt to make the seal pretty much sound proof. I am just worried about th materials deteriorating over time from opening and closing. I want everything in this box to be pretty much set-it-and-forget it.

I will post dimensions once I get the sound foam in and have everything measured.

[KitC]

Why 80mm fans? I just recently bought a case with 120mm fans and those were silent with pretty good airflow. As a matter of fact, my psu seems to make more noise now than my HSF and case fans combined.

[abyssinianson]

I will most likely only use one fan since the CPu box is pretty small (I am using the other 80mm for another project, not this one), and I imagine I can't be using more than one to move the air required for "X" amount of air  for the proper amount of air exchanges in the box. But I specifically chose the Nexus 80mm because I have worked with this specific brand of 80mm case fan before in my laboratory for another research project where I had to know what frequency its ambient noise was to calculate it into my resulting experiment conditions. A 120mm case fan gives off about 20db of ambient noise but I plan to undervolt the 80mm fan while still providing enough airflow. I project an ambient db of no more than 15db. If I can get the sound that low, making the baffle is going to be easier. So, I figured, knowing these fan specs is going to be useful in designing my sound trap because I know the fan well, I know its characteristics, and I know how to design the sound trap with its specific noise. I am designing a baffle around a muffler design where - hopefully - I can design a baffle efficient enough to generate destructive interference to cancel out whatever whine the fan gives off to accomplish my target air exchange value.

I want this thing to be as dead quiet as possible so I want to install a single control fan rheostat outside the case to control the fan speed as well.