I started to record more vocals in my home studio and wanted to get a better sound and after some research I found out what a "GOBO" was. I had seen these sound dampener things but didn't really realize what they did. Now I do. I found a youtube video of a great idea on how to build one that did not cost an arm and a leg (https://www.youtube.com/watch?v=WFVqcEpg6_c) by Dave Eric Smith but it didn't have instructions on how to mount it. I slightly modified it besides my own mounting option which I tried to keep with his idea of making this cheap and getting the parts at Wal-mart. Here it is. This build cost around $15 dollars (all things purchased at Wal-mart) except the foam (I had this on hand).
Step 1: Items You Need
Paint Grid x2 = $2.50
Spring Grip Organizers (PO-25) = $1.97
Mending Plates (HI-973) = $1.97
Machine Screws and nuts (MS-82) [#8-32 x 19MM] x (This build uses 6 but you might want 10) = $.97
Styro Glue 4fl oz = $3.97
Black PosterBoard = $.97
Acoustic foam (22x28 inches about) = $??
Step 2: Modify the Paint Grid
Open the ends of the Paint Grid so you can fit the other inside of that one. You will "sandwich" them together. I used some needle nose pliers and channel lock pliers to do this. I also used a hammer to get them deep into the slots and to pound them together. Be careful not to pull them apart too much as I made some of the grill frame come apart, but it was an easy fix putting them back together.
Step 3: Hammer the Ends Together
Make sure you got the ends of the Paint Grill as together as possible.
Step 4: Bend the Paint Grid to Shape
Now bend the Paint Grid to get a nice half circle shape. I didn't use anything circular to work off of, i just eye balled it, which is why it is how it looks. It still worked fine, so don't sweat it too much if it isn't a perfect half circle.
Step 5: Cut the Poster Board to Fit the Foam
My foam was shorter than the poster board, so I had to trim some off.
Step 6: Glue the Poster Board and Foam
Using the foam glue, glue the poster board to the back of the Acoustic Foam. Let this dry.
Step 7: Back Mount Bracket
You will need to bend two of the mend plates to fit the curve of the back of the "Gobo". I used a hammer and a brick on the concret floor to bend them in place. Make sure the holes of the mend plates line up. You will need one bend plate on the back and one in the front. You will need to do this twice because you need them on the top and the bottom of the "Gobo".
Step 8: Spring Grip Clip Hole
You will need to make the holes on the "Spring Grip Organizer" larger to fit the screws. Use a drill to make them bigger.
Step 9: Mount the Spring Grip Clip
You will need to make a hole in the Paint Grid so you can put a screw through it and mount the Spring Grip Clip. Do this to the top and bottom of the Paint Grid.
Step 10: Support Brackets
Using the bend Mending Brackets, sandwich them together on the bottom of the spring grip organizer clips as pictured above. Tighten them down as much as possible, it should make the Spring Clip pretty stable. Do this for the top and the bottom clips.
Step 11: Final Test
Test to make sure the Spring clips are able to clip to a mic stand. You could add more screws to the build of the mending brackets, you will just need to drill holes in the Paint Grid where the extra holes are on the mending brackets. Mine seemed pretty sturdy so I did not do that. I might do that in the future. Next using super glue or another adhesive, glue the foam/poster board to the inside of the Paint Grids and you should be done.
I added an MP3 file so you can hear the difference with and without the Gobo. In the test I removed all of the other dampening material in the room so you can see what just having the foam Gobo sounds like. You can hear more echo and reflection with out it.