Like the title says. During really low bass moments I always hear rattling coming from my basement windows. Upon further investigation I see that it is the slats in between the panes of glass that are causing the rattle.

Since I can't really fix that short of getting new windows does anyone have any suggestions on how to dampen the bass hitting the windows?

I have heavy theater curtains covering the windows and bass traps in the corners with GIK panels on the walls already.

I was thinking of buying some OC703 insulation (4 inches thick?) and covering that with fabric - sort of like a big pillow and stuffing that into the window opening. Would that be effective in dampening the bass from reaching the window?

Any other suggestions would be much appreciated.

Try a passage that causes the window to rattle, and then during that passage try pressing on various parts of the window glass and frame and see if it stops rattling. That's the only thing that will really stop the rattle, IMO.

Modern windows usually are a single piece of glass. To make them look like old fashioned windows with separate panes, they use a wooden or plastic grid that fits over the window. That is probably what rattles. Often those can be removed. If not, you could slip thin pieces cardboard of foam insulation beneath them to dampen the rattling.

http://www.asc-soundproof.com/windowplug-flyer.pdf

Thanks for the link Tom. those inserts look very promising. Any idea what they would cost aproximately?

http://www.asc-soundproof.com/windowplug-flyer.pdf
These look like a great idea.
I made my own. I think the key is to get a firm contact with the glass pane, and get lots of insulation between the outside (theater side) and the glass pane.

I used a piece for cloth on the window pane, a piece of styrofoam, then a piece of MDF to make my plug (http://tomdufresne.com/v-web/gallery/album03/theater08_060003). then I covered the whole thing with another piece of styrofoam and MDF.
Mass usually equals sound attentuation. YMMV

Best,
Tom
Chinaclipper