Strong bass causing buzzing behind the wall

That Warnes drum by the way, dobro I think its called, yeah pretty powerful and.... repetitive....

Thanks for the quick responses.

The other side of the wall from my listening room is the utility room with the furnace. However, there is a built in book case and a fireplace chimney between the two. From the utility room, I can see what the ducting and drywall wrap look like where it is above/in-front-of the bookcase. However, the part that is buzzing is above the fire place and on the other side of the chimney from the utility room so I can't get to it. 

It looks like the aluminum framing is about 1" high and the ducting sits right above this. I think the ducting is vibrating against the framing, so pushing against the drywall causes the framing to push against the ducting and stops it from vibrating. 

The aluminum framing is pretty flimsy so I am a little concerned that pumping too much of the foam through a small hole might cause the drywall to bulge. But I think this is still probably the easiest fix without pulling everything down (an expensive and messy fix). 

Jetter, the idea that this type of product can bend 2 x4 studs has not been my experience.  Are you speaking from experience, or just going by what you've read on the internet?

I am a little concerned that pumping too much of the foam through a small hole might cause the drywall to bulge.

Not a problem. The way that stuff works it comes out goopy and bubbly and expands. It doesn't push, just spreads out in all directions, path of least resistance kind of thing. You'd have to pump a whole can in there to have a problem. Maybe not even then.

The more likely problem is it goes in and by gravity or whatever just doesn't fill in the right spot. But you're really only out the cost of a can so what's to lose? Worth a shot.

213runnin
Yes, I did exaggerate a bit, on purpose to make a point to someone who may not have used the product. I would hate to see a tiny problem replaced with a big one. I had very expensive Marvin Ultimate windows installed where the installers used the expanding foam as a bit of insulation on two of the windows and to this day the windows are a bear to open and close. Yes, I have used it myself.

I do disagree with Millercarbon's benign description of the product just above.