How to make stackable Gobos

Instructable by Jim Robert ( Death By Protools )

Gobos are really useful things especially if you're working in a sub-par recording environment (ie. your living room). So what exactly is a Gobo?

Baffle - A physical object that absorbs or otherwise reduces the volume of sound which passes through it, or is reflected by it.

Gobo - see Baffle.

In other words, It absorbs or blocks sound. Those are the 2 main ways this effect can be achieved:

1. Absorbing the sound (converting it to heat via friction) - this is what foam, cloth, and other porous materials do.
2. Reflecting the sound (bouncing it back where it came from) - this is what concrete, and other non-porous materials do.

Here's a youtube video of the finished product:

Step 1 Gather your materials

Recipie for 2 Gobos:
note: Each step covers what to do for one gobo. You need to do the instructions from step 3 - 12 twice to complete both gobos.

Ingredients:

• 16 feet of 2x12 lumber
• 12 feet of 2x4 lumber
• 2 - 2' x 2' pieces of 1/4" plywood
• 2 - handles (I used cabinet handles)
• Box of 2" wood screws
• Fiberglass insulation
• A cover for the absorptive side of the gobo

note: I used pegboard for my absorptive side. I evens out the frequency response a bit, if you're not sure what that means, my advice is to use pegboard. If you want your gobo to absorb lots of high frequencies the you can staple canvas around the open side of the gobo instead.

Comments

[drugstoremarc]

Damn it, man. Awesome idea and beautiful execution. You've done a great job helping me out with this. Thanks a lot!

[popproject]

excellent idea and execution. i wonder if there might be a way to make the gobo lighter using a different material instead of wood. i.e. plastic storage bucket, cardboard etc...

[alexanderm]

You could, but keep in mind that different materials have different absorptive and reflective qualities. Some might argue that the more dense materials are preferred. Even the type of insulation used makes a pretty radical difference. Using layers of different types can assist in a more linear attenuation across the frequency spectrum. Personally, extremely dense insulation in the center, with a thin layer of lighter insulation, covered with a canvas is preferred. The 2x12 construction used in this 'ible seems a bit of overkill to me, personally... my recommendation would be 1/2" or 3/4" plywood for the top, the sides, the bottom, and the reflective side. If canvas is used with a non-rigid insulation, it may need to be braced up, to keep it from pushing out on the canvas too much. Just my 2 cents... as a professional audio engineer. ;o)

[Justinger]

Very nice instructable. Due to the nature of the insulation, I wonder if a version that is collapsible for storage would be possible? The portability alone is great though.

[carpespasm]

I would imagine you could rip the 2x12 boards in half to 2x6s and then put hinges inside so you can make them flatter but larger. there might be some problem with repeated or prolonged use squashing the insulation though.

[Zak]

Justinger, I'd think a zig-zag of strips of soft fibrous material (like used for some pinboards, or maybe even acoustic ceilings) could work and could indeed fold up like a screen. By not opening the zig-zak, but leaving the angles acute, damping will be better. Not tried this though.

[carpespasm]

These look like they would be very useful in setting up a home/garage recording studio. I might make some of these some time in 4ft units. Do you think the batting would stand up on it's own in that legnth or would it need some pegs run through it to keep it from "slouching" in the box over time?

[JustAboutRealJAR]

it'll work just fine... I have a pair of 4' x 8' gobos, that I built with the same size lumber. The only change you should make is to use thicker pieces of insulation so they don't slide, maybe R-19 or R-30

[frugal]

Aren't those 1x12, not 2x12?

[JustAboutRealJAR]

no they're 2x12. The reason the measurements only account for them being 1.5" is that 2x12's get milled down to be a little smaller, and end up being closer to 1.5 x 11.5

[gmoon]

Very nice, good job.

(The term Gobo is also used for light baffles. I.E., creating background patterns in photographs, "masking out" light, etc...)

[standupclothing]

Although I would never probably use a gobo, this instructable is very well illustrated!

=)

[TheCheese9921]

Simple and effective, I like it