gobo 'd mix area

[tonyfrancostl]

1st post here.

Thanks to all for the great posts and information and to the moderators and John for making this possible.

This forum is a truly rare and invaluable public treasure for the audio community.

My dilemna-

I am trying to build a mix space using gobos. The area I have to work with doubles as a rehearsal space for my band. I have some extra 1/2 drywall, so I'd like to use it in the gobos.

I'd like to keep the project under $500.

The room is 35'4"x14'5"x12"

The floor is 1/4" indoor outdoor carpeting over cement.

There is a drop ceiling at 7'10" that is the traditional 1980's paneled office ceiling, 1/2" I think.

The walls are the old fashioned plaster over board type construction and have a 1/4" layer of faux wood / formica on top.

The front door area and bathroom partitions are plaster like the walls. The front door in the drawing opens to the outside; in the partition are 2 steel grate open air security doors.

There are 2 rows of flourescent lighting fixtures in the drop ceiling, the one of the front door side 2' in from the wall, the other 4' from the wall. There are also 4 ac outlets/uptakes with the plastic style tubing going up to the ceiling unit as opposed to a steel duct.

I will have 2 moveable 7' tall MDF slat resonator corner absorbers from my isobooth could (?) be used in the mix area.

I don't need to worry about isolation in or out as the neighborhood is industrial and the outside noise doesn't bother me. The neighbors and I have worked out a schedule.

QUESTION:
Is there an optimal way to shape the mix area using wall to ceiling gobos?

Are the corner absorbers (John's DIY units) too large for the isobooth I am building that is 5'x6'x7' (inner dimension)?

Any insight would be greatly appreciated.
Tony

[jwl]

Hi Tony.

You'll want to experiment a bit with placement.

The most striking setup when you begin is to place absorbers and/or gobos in a circle around the speakers and the mix position. It really changes the sound. From there, start moving things around until you like the sound and things are balanced.

I built 6 gobos and 6 moveable broadband absorbers and use them this way all the time, it's a somewhat portable, modular design representing an improvement from an untreated room. It works both when I'm recording and when I'm mixing/critical listening.

[John Sayers]

Tony - I designed this setup for a friend - I've zipped it up as the image is too big to display.

he loves it.

cheers
john

[tonyfrancostl]

wow, Thanks John and JWL for the great insight!

I will reseach proper baffle speaker mounting techniques and high and mid absorber construction on the forum and get to work.

If I could trouble you with a few other quick questions 1st...

John-
1. is the long rectangular box (on the right wall) in the plan a side wall absorber or is it a crucial part of the plan, and is the other box in the back left a broadband absorber?

2. do you recommend building the units all the way up to the drop ceiling?


Thanks again for the help.
Tony

[John Sayers]

No - it's not part of the plan - it was for his gear rack.

I'd build them as high as you can go - the units are based on a typical 8 x 4 sheet of mdf being the backing. Put them on wheels and you can move them about as still use them to treat the room when rehearsing.

cheers
john

[tonyfrancostl]

good deal, John. I love the plan.


I've been digging around the forum for the breakdown of "types 1, 2" for different freq. slot resonator absorbers shown on your plan and can't seem to find it. Is this your own type of classification or a series of formulas I might find?

Thanks again
Tony

[John Sayers]

Tony - use this calculator.

Aim to cover the low mids from 150hz - 500hz

cheers
john

[tonyfrancostl]

I'm going to buy materials tomorrow , but first am trying to figure out-

if I'm using 2" deep 703, would it make more sense to make my depth of the low and mid absorbers closer to 4" (in the interest of saving $) than 6-8" to make best use of the 2" insulation? I have read in a reply post from Knightfly, I believe, that the helmholtz formula in this scenario works best using the 1/2 depth of the total space for the depth of the insulation.

and

If I am not decoupling the speaker box from its respective gobo, can the units be hinged to each other to avoid building stands for each or is coupling a problem?

pardon my abundance of greenitude, once again but I have been digging through the forum before I post questions. Almost over, I think...

Very excited for this project and grateful for all of your help and generosity.
Tony

[John Sayers]

Tony - as you can see from the calculator the deeper the absorber, the lower the frequency it will absorb. That's the important factor. Just put 2" 703 on the rear of the absorber and another 2" 703 between the front studs just back from the slots.

cheers
john

[tonyfrancostl]

Got the frames, speakers boxes and baffles built for the soffit / gobos, and front and rear mix walls, built two corner slat resonator frames for the iso booth corners but am stumped....

for the soffit / gobo slat resonators, should I partition the empty spaces with a vertical divider(s) to grab more frequencies??

or

if I am only using 1 cavity for the resonator, is it okay to put a thin (1"x2")center support strip in the middle of the cavity just behind the 4' wide slats to nail the slats into to keep them inline and if so does this affect the calculator?

I can't afford enough 703 to line the slat side and rear of each resonator; would it be beneficial to line the rear with unfaced fiberglass wall insulation?

THanks again
Tony

[John Sayers]

for the soffit / gobo slat resonators, should I partition the empty spaces with a vertical divider(s) to grab more frequencies??

or

if I am only using 1 cavity for the resonator, is it okay to put a thin (1"x2")center support strip in the middle of the cavity just behind the 4' wide slats to nail the slats into to keep them inline and if so does this affect the calculator?

I can't afford enough 703 to line the slat side and rear of each resonator; would it be beneficial to line the rear with unfaced fiberglass wall insulation?

THanks again
Tony

yes the vertical strip is fine Tony. What's in the resonator can be anything that absorbs - i.e. offcuts of 703, old blankets or curtains etc. Just stuff it with anything

cheers
john

[tonyfrancostl]

Broke until friday....almost there. Have taken a bunch of pics to share if I finish before the building is sold and I have to move again!...

I'm about to put in the insulation and slats.
but first....

John-
The plan you posted shows that the 2" slats are targeting mids and the front and middle 4" slat walls are targeting "lows"

I understand I'll be targeting 150-500 hz and have read from your posts that going lower than that won't work well for this type of absorber.

Should I target only the lower half or less of that range for the 4" slat absorbers?

Much appreciated
Tony

[John Sayers]

Hi Tony - here are some pics of the finished setup, with a few mods since the original design.

cheers
john

[ZSXI]

I know this is a really old thread but I've been pondering this idea lately. It seems like a great compromise for a diy single room studio, which I happen to be working on. I wonder if anyone else has tried this or if John has any recent thoughts.

Advantages I see:

• Monitors can be pushed back to the wall, making more room for tracking while still allowing non-critical playback.
  
  Optimal positioning could be tweaked with testing, marking the best position for repeat-ability.
  
  Just about any near/mid field monitor should work. No heat issues with active monitors. Reasonably easy to retrofit for new monitors.
  
  While in "mix mode", there will be some space behind the gobos for temporary storage of stuff you don't want laying around and causing reflections.
  
  Most of the above would apply to the rear gobos too. The backside of those could be made reflective for extra flexibility (in "tracking mode").
  
  Stretching this further, the concept could also be extended to surround sound setups...

What are the cons??

[ZSXI]

Bumping this one more time. I'm getting a lot of negative feedback on this idea elsewhere mainly because the gobos wouldn't be massive enough to avoid resonance issues (I assume). Though I'm not sure what makes this different from a stand in that sense. It will weigh more than most stands. It's just a stand with resonant filters and a large baffle -- which is rather unique I think.

I really am tempted because it solves so many issues I've been trying to address in a one room design -- but will probably drop it if I don't hear back from John or anyone who has tried it.