Dealing with Transformer and HVAC

[peferling]

I do video editing and occasional VO for my company. Most of the stuff is in-house training stuff.

Anyway, I have a two room office/studio that has high ceilings, flat walls and is very old. The hvac ductwork runs overhead and dumps into both rooms, with a mere 1/2 inch of ceiling tile for cover.

Second, I moved in while construction was underway, with the assurance that a large battery transformer, used as backup for the computer network, would be relocated. Which did not happen. So now I have this very noticeable hum coming through the walls. I'm certain the walls are hollow with gypsum on boths sides.

Anyway I covered the one wall with 3" foam, which damped it somewhat. I also converted a small coat closet, opposite this wall into a VO booth. No problem there. However, I'm tired of using software to kill the hum when shooting in the studio. I don't wish to use foam, as it's a fire hazard.

So what is my choice? Do I build another wall inside the studio, and if so, what design method should I follow? Would it be beneficial to seal the HVAC vents that dump into the rooms, or use a special baffle? From what I've read here so far, just hiring a contractor will not suffice. I feel that I should do some homework and then instruct the workers on what is needed.

I'm also coverting my garage, so anything I learn here, I can apply to my own at home : )

Any insight would be much appreciated.

Thank you.

Pete

 

[peferling]

Transformers and HVAC

I'll rephrase the question: When dealing with nearby humming electrical equipment such as transformers, am I looking at 5 feet of concrete shielding, or would an easier fix be in reach? (Relocation is not possible).

Thanks.

 

[mshilarious]

I'll rephrase the question: When dealing with nearby humming electrical equipment such as transformers, am I looking at 5 feet of concrete shielding, or would an easier fix be in reach? (Relocation is not possible).

Thanks.

There are a lot of threads on this board for proper wall construction, look for them. But essentially you fill between those walls with insulation, with all gaps caulked. It also helps to add another layer of drywall. You should be sure that the wall extends all the way to the hard ceiling above, not just the drop ceiling.

To isolate the HVAC, you basically frame around it and do the same thing. For the vents in the room, yes you build a baffle at the end of a long run of that flexible vent stuff.

Two interesting problems: The transformer will probably transmit vibration through the floor, and it might throw off a fair amount of interference. You might have to build a floating floor in the studio. You also might have to shield around the transformer, or shield the room. At the least you'll have to be sure to strictly use balanced, properly grounded connections.

For sound treatment, there are nonflammable foams, but they are ugly. What you want is a proper rigid fiberglass insulation system. If you are interested in professional installation, I can send you a link to a commercial wall system distributor, please PM me for details.