4'x4' studio gobo's for Acoustic Sessions in Studio

[davidki]

I am planning on building some 4'x4' gobos for our studio. I built some gobos that are about 5' height x 4' which are great.. but I find that here in Nashville musicians like to record together in the room (kind of like the Beatles) so, I decided what the heck build some smaller gobos so, here goes my idea (remember these will be used mainly with acoustic guitars, mando's banjo and smaller acoustic instruments. The musicians will be sitting down, so the 48" size is about right.. I will tie 2 of the gobos' together with hinges so I can move them at angles to fit our need.
So, here is my design idea.

Use 1"x8" frame, In doing this, I can build a small area 5" -5 1/2 center between 2 pieces of mineral/sound board material. the outer side will be 703 1" fiberglass board and cloth on the outside of the units are Gilford Of main cloth. ( I have allot of 703 and the Gilford cloth from my studio build).

It was suggested I just use "Pink" fiberglass batting in between the mineral board (I have about 2 rolls of unfaced R25 in my attic I'll just shove the insulation loose in between the 2 pieces of mineral board. I wish I had a drawing to add to the post..

Here is the inside of our studio http://www.eaglecanyon.com/pages/studiolayout.htm

Again, the gobos are just to use while tracking a rhythm section of acoustic musicians and I"ll be using close mics on the instruments. I"m not to worried about a little bleed in the mix..

[John Sayers]

David - here's a sketchup file I created for a gobo design - it's 8' x 4' but you can easily adjust it to 4' x 4'

gobo_imperial.skp

gobo_metric.skp

just keep hitting 'page down/up' to toggle through the scenes.

[davidki]

John, Thanks for the design you sent along, I have a couple questions on your design vs my first thought.

In my original idea I had thought by putting an area packed with insulation in the middle would help in the absorption.... that is why I put the 2 sheets of mineral board and the fiberglass inside of it. and on each side I would use the 703 I already have. I was not planning on a reflective side on the gobo's (I'm not sure I'd ever use them.

From the look of your design it looks like you use 3" 703? So, would I stack 3 pieces of 703 since mine is only 1" material?

In my design I ended up with an 8" wide (thick) gobo and I thought that would be better for absorption. Are you saying I would not need the thicker design for what I want to acheive.. These are to use in a 2 or 3 instrument set up in our studio where all the musicians will be sitting facing each other.

Your design sure would be easier to build, that's for sure.. .

Dave

[davidki]

John, One more piece of information.. the fiberglass board I have is actually made by john Mansfield, it is 1" 3lb density board. One thing I'd like to get is fairly good isolation between instruments, a friend of mine just built some gobo's for his studio, they are packed internally with Rockwool as he didn't have any fiberglass board.

So, given my insullation density of 3lb vs a 6lb density how would that affect my gobo in your design? from the look of the design is there an airspace in your design or is the fiberglass right up against the backboard?

If I need to go and get some 6lb material I can do that as well. In your design, you have 2" is there any benifit to go to 3" material?

[John Sayers]

David - go with 3 layers of your 1" if that's all you've got. You can always adjust the plan so there is insulation on both sides.

[davidki]

Hi John, thanks so much for your response.. the material I have that I used in my studio is Manville 814 so, I will use 3 sheets as you suggested. I am also going to leave the one side reflective for now as your design shows, were going to paint it. If at some point I want to add fiberglass on that side, I can do that easily and just build a 1x1 frame for the cloth...

Thanks again for your help..
Dave

[davidki]

Hi John, well I thought I'd update you and the group on my gobo build...

I took the designs you posted for me and made a few changes per our discussion.. a friend of mine who is a finish carpenter did the build out on the frame and main encasement, I filled with fiberglass and my wife and I streached the Gilford material over the frames.. they turned out great..

Materials:
6" poplar wood main frame, on one side of the frame is built for 3" of 703 fiberglass board, the other rather than having a reflective side, I used a 1" 703 for the design. 1" plywood between Fiberglass board. Each Gobo is 42" high, 48" wide, we used hinges with pop out pins to allow easy moving and storage. You can see the photos below in progress and the final product just finished today.

Cost Wood frames and enclosure total $400.00 (3 sets of 2)
Labor: One day finish carpenter $200.00
Aproximatly 50 yards of Gilford Marine fabric
Fiberglass board Aproximatly $300.00

All in all, not bad, most commercial built are running about $400 ea.

[John Sayers]

They look great David - are you going to add wheels?

[davidki]

Hi John, thanks for your nice words, I didn't use wheels, I put some of the material that you use under furniture legs on the bottom, so I can slide the units in to place.. I figure I can always have my wife help if no one else is around

I was thinking of doing a test with a speaker on one side either a tone or maybe a acoustic guitar player and measure the attenuation it be kind of a fun test. What kind of attenuation do you think we will get John with the 3" of 703, 1" plywood and the 1" 703 on the outer side? Anyway to calculate that.

I was fortunate that we had this finish carpenter here doing some work on the house, I could not have built the frames so well and so exact myself.. he really did a great job... and for $200.00 labor, that is cheap!

I am looking forward to finding a project to test them out... I imagine they would be great around a set of drums to help isolate as well.. I have some 6' gobos built on wheels, I could use them on 3 sides and then these in-front .. all kinds of options, right!

Thanks again for your ideas... .as you can see they turned out great..

Dave

[shamca]

Hi Dave - I was just looking for good gobo ideas and your hinges just turned a light bulb on! Thanks!

I was admiring your studio and wondered if you could tell me about the resonator that's all along the walls?

Cheers,
Shaun

[davidki]

HI Shawn, thanks for the note, and thanks for the comments on the Gob0's, they are great but heavy

The diffusers along the wall were designed by the guy that designed our studio in California and here, the are a combination of hard woods and sizes placed at various distances.. We had a cabneit maker here in town build them for us.. it ends up to be about $100 per foot to build.

I see your up in London Ont, We just finished a project with www.mariamacdonald.com Maria had a bunch of fun recording down here with us!
Dave