Paul, those Gobos sound like they could be really useful. Do you have a link or anything to a DIY project, or more info?
I don't but they are very simple to build. I made mine 8" thick. If you buy Roxul comfort board insulation http://www.roxul.com/products/residential/products/roxul+comfortboard+80I use 4 Pieces thick per gobo. Build a box out of plywood around it to hold it together and wrap it in fabric that is breathe able. I buy clearance fabric by the bolt. You can place these at first reflection points or over corners when mixing and then place them around the player when recording. I built 16 of them but I need a ton of them. 6 Pieces of comfort board is $50CDN on piece of plywood will do 4-6 gobo at $17 and the fabric can be very cheap.
Thanks for the info! I was looking into it the other night as well; seems like these things are super heavy. I'm looking into acoustic blanket type options as well.
The wood is the heaviest part. The insulation is pretty light. Acoustic blankets won't have to mass to control low end unless you get into some sort of limp mass which is very heavy from my limited understanding