Room treatments

I did not mean to imply that Sonex was ineffective. Nothing like that. Nothing that good. What I meant was that it sounds terrible. Even in very small amounts. It makes the sound all phasey like and wooly, unnatural. Sonex use in recording control rooms completely covering the walls would be a sonic catastrophe, a sound apocalypse, messed up.

GIK superior to ASC Tube Traps? Au contraire!

Masterplan...10' ceilings, OK.  What's the room dimensions?  Couldn't find your pic of the space....having lived in a Victorian with 10' ceilings and a small room with plaster walls to boot, know how it can be an echo chamber.  Now I've got 12' ceilings but not so echo prone...*G*

The first step to problem solution is problem identification ... Can't measure it .. Can't mange it .. purchase a calibrated mic .. good outboard sound card and add REW to your lap top

Get familiar on how to measure your room and what the measurements mean ... then you can correctly and effectively treat the room

Your room behaves in two states .. above and below a transition point referred to as the Schroeder Frequency

Above the room's transition point frequencies act like Rays or Beam of light ... because their wave length's are shorter than the room's dimensions ... they will projecting from the speakers in a straight line until they strike a surface and are reflected ... you must apply traps at the point of contact to reduce the unwanted reflections

Below the room's transition point the wave lengths are to long to fit inside the room's dimension and they Pressurize the room unevenly instead of Beaming ... you must trap those at the points of highest pressurization in the room or in the 4 corners and the mid point of the walls where pressure is highest

There are plenty of traps designed as wall art from GIK and Acoustimate ... the room nee-dent look like House and Gardens meets Hell's kitchen 

@masterplan - another product I have used with great success are the 2' x 4' vinyl faced fiberglass ceiling tiles used in drop ceilings.

I created a 4" thick "brick" (about 6-7 tiles) with the vinyl sides facing out.
I covered the brick with black landscaping felt to prevent  the little glass fibers from falling out.

I placed the brick under the sofa and at the back of chairs (we had hardwood floors) but if you have carpet then they would probably not be required.

You can also use them behind canvas pictures for additional damping effect.

Just use a sharp carpet knife to cut them

Regards...