Resonating wall.

Hi, i'm looking for some advice on a problem I have. I have renovated a small studio I have access to, a small room roughly 4m x 5m, it previously consisted of a wooden frame with fibre glass covered in cloth. I replaced that by fixing the frame, creating more panels, filling with fibre glass and insulation batts and covering with yellow tongue flooring (19mm). With the idea of using that as a firm backing for adding extra treatment. This was done in summer and y'know, did the job. As it goes, come winter the building sounds pretty noisy and the studio is droning. It turns out the central heating for the building has been turned on and a pipe from that which feeds my side of the building comes into one of the studio walls. The walls are double brick with say a 2 inch gap but the wall is vibrating, what's more it has created sympathetic resonance and there is a bloom or flame that extends to at least the middle of the room. It's really full on. I'm not sure what to do about it. I didn't notice it so much when the studio was "cloth" so I guess the renovation caused the problem, the frame is attached to the wall and the yellow tongue is screwed and nailed to that and the cavity is pretty packed. I'm wondering what I need to do to at least puncture the sympathetic resonance. Should i cut holes in the offending panels to release the tension? A friend suggested adding mass to the wall. I'd very much appreciate some advice. thanks, simon

Simon, I reread your post a couple of times, and it's still hard for me to understand your situation.

what's more it has created sympathetic resonance and there is a bloom or flame that extends to at least the middle of the room. It's really full on.

What is a bloom or flame that extends to the middle of the room. Is that brick wall vibrating? How is that construction exactly. What is that flame or bloom?. Is that a mass-spring or other resonance somewhere excited? I have the feeling that you either much sketch this situation (sketchup) or that you ask someone with more experience to have a look locally. You have trouble with structural born sound on heavy brick walls. From burners thats most likely very low frequent ... Don't do anything before people have a better picture what happens over there. Read your own post. Imagine you have no idea of that project (it's one of a third unknown person). Should you be able to imagine that exact situation? Just taking distance from your own post, helps you to check the clarity of your own question. Maybe others understand better than I do.

Eric_Desart wrote:

What is a bloom or flame that extends to the middle of the room?

I think its a concept from "Mixing with Your Mind" for thinking about the sweet spot for mixing - from a setup and mix process perspective. http://www.mixingwithyourmind.com/ highly recommended book btw.

Hi Eric, thanks for considering the post, sorry it isn't very clear. Yes, the concept of "flame" is influenced by terminology used in "Mixing with your mind." Essentially, the heating pipe is causing the wall to vibrate. Not only is it vibrating it is singing a low frequency hum, like a drum resonance except that it is constant. By "flame" I mean this. If I was to walk across the room with the offending wall on my right, I would start with the resonant sound from the wall being barely perceptible, as I walk across the room the sound of the hum increases in volume until it reaches a maximum near the middle of the room, then it starts to subside as I reach the other end of the room. Basically there is a low frequency vibration that extends into the room in the shape of a bell curve.

Simon, At a first glance that sounds as if this resonance coincides with the first even order axial mode. But that's guessing. If you use wood on that wall, that's still not clear (you really should make a sketch with exact measures, cavities and so on from all this or this becomes endless), it can be a mass spring resonance. Basically you either need to decouple that wall (can go further than that wall, since that wall can be excited by other walls or floor) from that equipment (or the way around). I can't judge from here what's needed to do so. The only alternative is to isolate your studio from that brick structure, and taking into account that you're speaking LOW frequencies, that calls for care in function of MSM as well. The normal basic rule with structural born sound is decoupling, meaning preventing the phenomenon to establish (primary solution). Normally only when that proves impossible or impractical one goes to secondary solutions. I can't judge from here how that wall excites your other stuff and construction.