What can we do to improve our layout?

I have a radioshack SPL meter. Just stopped into the new space... at 3:30pm there was about 57db of noise in the control room. In the live room near where the window is, it would spike at 71db when a loud truck drove past, otherwise the average level was in the low 60s. There was not any noticeable noise from the automotive shop, the most was traffic. With the heat or AC cranked the loudest I could get it to measure was 70db when I stood right under the vent the air was coming out of. Other areas didn't seem affected and there was no noticeable vibrations from the AC or furnace! It may not be directly above the studio area (I can't tell without going on the roof, and there isn't easy access to the roof). So, I think it relatively good news - the window is the biggest culprit of noise pollution. I will try again around 1-2am just to compare.

That sounds like good news! But you do have a noisy environment to deal with. Those levels are a little high to be able to record and mix in! :shock: Have you set a goal, in terms of NC curves, for what you'd like to have in your control room and live room, after everything is finished? You might want to look into that. It seems like you are currently in the ball-park of NC-60, and you probably want something like NC-25, I guess. Does that sound about right? One thing to note: If you are getting a high reading right under the HVAC duct, then that is either due to fan/compressor noise entering though the duct, or to noise from the air itself moving. Either way, that is going to need some treating. Once you get the rooms properly isolated, that HVAC noise is going to be quite noticeable, probably annoying, and definitely problematic for recording. For studios, the idea is to move large volumes of air at very low speeds, rather than small volumes at high speeds, so you'll need to get that modified, and you'll also need to get the ducts lined on the inside, plus in-line silencers and multiple 90° bends in the duct work. You will most likely also need to get the ducts decoupled from the air handler, and also from the support brackets. So HVAC is probably the first thing that you'll need to look at, since that work has to be done before you can start on the isolation. And if you are going to do all that, you might even want to make the most of the opportunity to have the ducts re-routed or use ducts that don't take up so much headroom, so you can get more height out of your rooms. - Stuart -

First of all, thank you to everyone for all your collective ideas. We are getting a much better idea of what we're in for and all of this knowledge is incredible! We're seeking some local advice on the HVAC and we'll post more when we can get some insight from a more knowledgable party. I went back to the space after everything had closed... the sound levels were generally too low to register on my radioshack meter which has a minimum reading of 50db. Also, in the next year, the city of St. Paul is going to be building a light rail line on the busy road which is already noisy. So there is no way to measure for the future, but construction and the sound of train is coming.

Our HVAC expert didn't have much of a background in audio or soundproofing, so he was looking for more information or plans on what we are looking to do. Soundman2020 suggested multiple 90° bends in the duct work. How many or how frequent do the bends need to occure? How do we decouple the ducts from the air handler. Should we start a new thread about HVAC? That definitely looks to the be breaking point at the moment. Thanks for any help!

I have some links, they mostly point right back to Mr. Sayers forum: http://epaper.buildthisroom.com/heating ... enums.html Specific details can be located in the link marked "Mini-Prod Studio - Construction Phase" But these are at least the most current and informative that I have been able to get my hands on.