First off, my apologies for asking this, as I'm sure that it's been touched on several times in the past. The AVS search engine and I just do not get along it seems.

My situation is pretty simple. The room in question is basically a converted bedroom (12'w X 16'l). Due to budget constraints, sound isolation and total sound treatment just aren't in the cards for this "phase". However, I will be applying some basic treatments. The front wall is currently covered with linacoustic, and I plan on building some simple panels to treat 1st reflections. It's not an ideal situation by any means, but I suppose it's a start.

So anyway, here's my question: I'm toying with the idea of building columns on the side walls (likely 4"x10" - one on each side). Is it recommended to fill these with insulation?

Simple answer - Yes!

You should fill all larger hollow closed areas with insulation to avoid that they are starting to resonate at specific frequencies.

Simple answer does the trick. Gracias! :)