Gobo with OC 705

[gabehizer]

I have 14 24" x 48" OC 705 1" thick panels left over from a project and thought I could use them to make some gobos. 705 is the stiff, more dense version of the more-commonly used 703 insulation.

Should I double up the 70 panels within each gobo (i.e., to achieve a depth of 2") or is it sufficient to have just one level of insulation per gobo (1" thick insulation)?

Should I build each gobo 2' x 4' or double width (4' x 4')?

Thanks!

Gabriel Heiser

[Soundman2020]

Please read the forum rules for posting (click here). You are still missing something!

Since you are using 705, it seems that you only need to deal with mid and high frequencies, not low frequencies? It's unusual to design a gobo like that, so 'm wondering why? Most gobos cover the full range.

But if you only need to deal with highs, then probably 2" is fine.

Regarding size: what is the purpose of these gobos? How big is the live room? What type of instruments will you be tracking in there? HOw man instruments at the same time? That info would help to provide a realistic answer.


- Stuart -

[gabehizer]

OK, here is the missing info:

I am about to start constructing a few gobos, using 14 2’ x 4’ panels of OC 705 that I have left over from another project.
The tracking room is 20’ x 18’ x 21’ ft high.
The room is covered in Troldtekt panels (on 3 walls) with 2" fiberglass behind them, and with 24 2’x2’ diffusers hanging from the ceiling.

I would like the diffusers to assist in helping isolate instruments (e.g., drum set, guitar amp, etc.) one from the other, to improve separation when recording multiple musicians together, live (probably no more than 4-6 at a time).
I am not looking to tame the overall acoustics of the room with these.

I hope that helps! Thanks.

[Soundman2020]

I would like the diffusers to assist in helping isolate instruments

Diffusion won't separate or isolate instruments. Neither will absorption by itself. To isolate instruments, you need mostly mass: Gobos are normally built with one large, heavy panel on one side, and often absorption on the other side, or even on both sides of the panel. Depending on what instruments you are dealing with, you would chose which side of the panel to use. The more isolation (separation) you want between instruments, the larger and heavier the gobo needs to be.

The choice of insulation also plays a role: since 705 is high density, it does not do very well at absorbing low frequencies, such as drums and bass, but does fine with mids and highs. So you might want to use a series of such a panels with the 705 facing towards the drum kit, surrounding the kit, so as not to affect the sound of the kick and snare within that area, but damp the crash and ride a little, while still providing a few dB of isolation from instruments around it. Of course, that gobo would have to be at least as tall as the highest cymbal, plus a foot or two, to be effective.

The tracking room is 20’ x 18’ x 21’ ft high.

That's a nie sized room, especially the height!


- Stuart .

[gabehizer]

Oops, I meant I wanted the new GOBOS--not diffusers--to help isolate the instruments one from the other.

OK, thanks much for the tips! That definitely helps me figure out how to construct the gobos.

Gabriel