single unit air handling system.

Hello. I am building a small studio within larger office in a modern office building. I have an enclosed space of 10 x 15 feet with around a 7.5 foot ceiling to work with. There is a very loud low frequency hum that comes out of the ventilation system and I get the feeling that it will be easier to get rid of it by removing the vent ducting from the main system and installing a small independent ventilation system that can simply use the already-conditioned air just outside the studio area. Can anyone recommend a small quiet unit? I don't believe that I will need any conditioning; just a unit to move the air that is quite quiet. Thanks for your help. Jason Levy

Jason, you're not the only one who does this and I'm trying really hard NOT to jump on your case, but is this post NOT visible? http://www.johnlsayers.com/phpBB2/viewtopic.php?t=3231 For some reason, no one seems to be able to see it; as I said, it's not just you. IF there is some way I can make it clearer, I'll do it. Just let me know. IF you read that post, I hope you'll understand my frustration; it's 4 am where I'm at right now, and I'm still up answering posts instead of sleeping at least 4 hours. A fair part of the reason is that people tend NOT to give enough information so I can help them - that's why that post is at the TOP of the forum. Believe me, I'll never accuse anyone (except as a joke) of giving TOO MUCH information. Sorry if I'm coming off as bitchy, but please read and comply as much as you can... Steve

Sure no problem. I just thought because it was only a very specific piece of information I was looking for that I would not trouble you all with a lot of details. We are at the very beginning of this project and have no specific plans yet. We are just looking at some of the issues so we can try to make some decisions. We mix television shows. We do not work very loud ( around 70 db) but we hope for a very silent work environment. It's a modern office building with concrete under the floor and the usual ducting and wiring above the acoustic ceiling tiles. Room is 10 x 15 x about 7 feet high. I am hoping to do the basic room for around $10,000. My question is very specific; I am looking for a small and not exorbitantly price ventilation solution as there is a lot of very loud low frequency sound coming out of the central system. I appreciate resources like this very much and I thank anyone who takes the time to read this. Jason Levy

I appreciate your not taking my fatigue-induced comments as a personal attack, they weren't meant as such :? This sounds exactly like what Keith Sharward has been researching for his drum iso room; you might see if he can point you to the fruits of his search for more on air movers. I personally think you're on the right track; if you can get your room isolated (need more on floor weight ratings before I can help with that) then use a couple of silencers to allow conditioned air in and out, you should be in good shape. If you can, find out who's the engineer for the building and ask what your floors are rated at; this will be either in pounds per square foot or in kG per square meter. This will tell us what you can do toward building a room-in-room approach; Also, aside from the air con noise is there anything else you need isolation from that's fairly loud? If so, actual SLM readings would be helpful... Steve

I am very well acquainted with the feeling of having worked too much and slept too little so you have my complete sympathy. I am also very very grateful for any advice on this topic as I need a lot of help.

This sounds exactly like what Keith Sharward has been researching

Will search for that thanks.

need more on floor weight ratings

I don't know what that means but I'll find out.

find out who's the engineer for the building and ask what your floors are rated at

Again I don't understand but I'll find out. You mean how much load can they bear?

is there anything else you need isolation from that's fairly loud?

Nothing much more than the sound of people walking around and talking. We are in the center of the building away from the street. There is no heavy machinery in the building. Again thanks. Jason

knightfly wrote:

This sounds exactly like what Keith Sharward has been researching for his drum iso room; you might see if he can point you to the fruits of his search for more on air movers.

Here's the place in my marathon thread where I start discussing the Faantech heat recovery ventilator. Don't miss the parts of my thread where I discuss the silencers. --Keith :mrgreen:

Thanks very much, Keith! A number of very interesting products on that site... Jason

Would it be unworkable to re-do the ducting in the room? Most office HVAC stuff I've seen just uses bare galvanized ducting. If you add a pickup point in the outside office area and then run new ducting (made with fiberglass ductboard) to the studio, plus add a silencer on the inside and outside of the room (4 total), you might be able to reduce the noise level to something more acceptable. len

It's something I considered. I guess we're going to have a look at the possibilities when I go over with my builder next week. But I worry about how big a job that is going to be.. which leads me to wonder if just installing a parallel system might not be less expensive and less work. There is a pretty ferocious noise coming out of the thing. I guess we will do what gets the right results for the least trouble. We are occupying a space in the middle of a fairly large floor; 12,000 sq. ft. so the duct is a big one (i'm guessing!) and it's a fairly long run. I haven't completely written off that option. Thanks for your very clear suggestion. Will definitely be having a good look at that possibility. Will take some pix. Jason