VO booth construction

My upstairs edit suite needs to accommodate a VO booth and a good space of accurate mixing. The booth's dimensions are likely to be rather odd, since the best scenario I can think of places it against a sloped ceiling that drops from a high point at a 45 degree angle stopping at the 4ft mark and dropping straight vertically. It would have to be free-standing, but that's good right? The box would be roughly 6x8 with one of the long walls tucked into the slope. (odd, huh?) If this is some kind of impossibly untame-able shape, I could change it, but this plays havoc with other plans. I have a budget of about 2k - but naturally would be glad to spend less if the results are not compromised. Thoughts, anyone?

I read with some interest the thread about a video studio and the attendant sound considerations. I'm in a similar boat, but I am interested primarily in creating ideal spaces for recording voiceovers (narration/voice-acting) and accurate mixing. I read the accoustics 101 primer at the auralex site, but am wondering how much of all that applies to me being voice-only. I also ordered "How to Build a Small Budget Recording Studio from Scratch...with 12 tested designs" I'm looking forward to reading that.

A couple of more specific questions: Most of which are about using commonly-available materials that mimic the function of brand-name (expensive)accoustic construction materials.

I am wondering if the premium underlay material for Pergo/hardwood floors would work in a similar fashion to SheetBlok from Auralex? It's a very dense closed-cell foam sheet.

Floor surface: What to use? Carpet? One kind better than others?

Under the floor: Thinking of resting 2x4 "joists" on evenly (or better unevenly?)distributed garden step-stones topped with some thick rubber "anti fatigue" matting. (looks to be similar in function to U-Boats for Auralex)

Corners: Should treat them after, or build them out differently? Specific dimensions?

Walls: Thinking of using framed pieces of absorption material hanging on textured drywall. I can add or subtract "liveness" as needed - yes?

Doors and windows: help me out here, people.

Control room: Again - I am a blank slate.

Thanks!

Ron Grandia

Hi Ron,

Regarding what Spot suggested about the floor isolators. You can buy something like he's describing readymade very cheap. On my booth, I used Isoloation pads that are designed for mounting High wattage Power Transformers, motors, and the like. They are essentially a piece of 3/4 inch cork sandwiched between two pieces of corrugated hard rubber. They cone in sizes fron about 2"x2" up to 6"x6". Glue several of these to the bottom of your platform, and they work great. They cast one or two dollars each.

They can be had from Graingers, electrical wholesale distributors, etc..

I built the base for my booth, by firat laying down a layer of 3/4" MDF (Medium Density Fiberboard) which is like Particle board, but much denser, and twice the cost. Then I placed one of those rubbery mattes on top of that, that are designed to keep rugs from sliding on hardwood floors. Then, I placed another layer of MDF with the joints perpendicular to the first layer.

Next I built the base itself out of two layers of 3/4" MDF glued on each side of a 2x4 framed (16" 0.C.) structure, and filled with lots of R30 fiberglass. I built these with a custom tounge and groove design so that the three 4x8 sections interlock. I glued several of the small iso pads described previously to the bootom of each section an set the whole thing on top of the two layers of MDF that are on the floor.

Then I fastened a 2"x4" wall structure to this which (with 1/2" particle baord glued to the back) which accepts custom made soundproofing panels I built from 2"x3" framework with 3/4" MDF backs glued to them. These were filled with two and a half inches of Owens Corning R704 fiberglass sound board. These were covered with burlap that was attached to the soundboard with 3M spray on contact cement. And each covered soundboard section was fitted into the framed soundproofing panel. The panels were them fitted into the openings of the walls.

Once the walls were up, I duct taped all seams on the floor and joints where the walls met the floor, then I placed another layer of 1" MDF on top of that to complete the floor section. This was taped together, then carpeting was placed on top.

The ceiling structure was constructed using a similar method as the walls, but the panels are 2"x4" (as opposed to 2"x3") set in a 2"x6" framing structure which holds them, and are filled 3 and a half inches of burlap covered R704 panels.

R704/705 is a very dense fiberglass material commonly on the walls surrounding large deisel power generators, A/C systems, Deisel Fire Pumps, etc. of large commercial structures (like high rises) to absorb sound. It works very, very well. It comes in rigid sheets in thicknesses of 1", 1.5", 2", and 2.5". The sheets are available in 2'x4' panels (for use in T bar ceilings) or if you want to buy by the pallet, they come in 4' x 10' sheets (40 sheets in a pallet).

The booth I built is very soundproof and sounds pretty much acoustically dead inside, which is desireable for such a small room (8' x 12'). I create room ambience artificially with digital reverb. It's completely portable, but I use the term loosely as it consists of a lot of heavy pieces, and is a 'lot' of hard work to move.

Given the dimensions you stated and the purpose, I would think you'd want it to be pretty dead too.

My booth is currently disassebled as it is being enlarged (it was previously 8'x8' and is being enlarged to 8'x16'.

That book I suggested will give you a lot of great ideas on how to build your booth 'very economically', and better yet will give you enough 'why' information to build just about any kind of a sound containment structure/room/booth you might want.

Mark Simpson

That book will help a lot... I've been recommending it for a long, long time and never had a complaint yet... B^) There's a reason it was one of Mix Bookshelf most popular sellers.

Mark Simpson

So d'ya think I need to go through all that hubbub for a VO booth?

Not likely, unless you are in a pretty noisy environment where you need to keep the noise out.

However, the R704/705 soundboard covered with burlap, makes awesome wall treatment, and it's easy to make look nice. You can get some pretty classy burlaps at any decent fabric store. Build yourself a drywall over steel stud (or wood) room, with a wood and full length double paned glass door (from your local home depot. try not to make it cubic or sqaure, but give it a shape that has not parallel walls if possible. Build yourself some boxes using 1/4 plywood backing framed with 1x3 pine or redwood. Get some 2.5" thick R704 soundboard panels (2' x 4') glue the burlap onto that, and then slip the soundboard/burlap into the framed box, so that the burlap is facing out/showing.

Hang several of these on the wall (better yet, completely cover the walls with them). You can also get some 54" square fire treated eggrated style sound foam from markertech for about $20 each. cover the ceiling and or one of the walls with this. Also, louvered window shades make great diffusers. You can stained ones and fasten them to cover some of the soundboard panels. They look nice and are much cheaper than the auralex style stuff.

Mark Simpson

Staggered studs looks to be the best route for the walls, and an MDF sandwich floor oughta do the trick nicely.

To me, this sounds like overkill for VO, unless you live next to an airport. freeway, or train depot.... 8^) However....

Staggered studs will definitely help stop transmission. Double up the dry wall too, if you really want to do the STC thing. If you really, really want to isolate using drywall construction, use Z channel, or hat channel to seperate the two layers of drywall on one or both sides of the wall. Make sure the whole shebang is airtight, but allow for some sort of ventilation. Ideally, a tie in to the building A/C, but with as much isolation as possible. Sound can travel through the A/C system.

I have a bunch of 1" thick dense fiberglass sound absorbing panels that came with a painted cloth covering. I made frames for these and they hang in my current studio. They seem to be working well for wideband absoption. Do these pass muster d'ya think?

That sounds like the same stuff, but I can't be sure without seeing it. Thicker is better. The thicker the fiberglass panels, the lower the frequency absorbtion dips. A general rule is that your absorber will work with frequencies whose quarter wavelength is the same or smaller.
So if the wave length of a certain frequency is 1ft, then it would require 3 inches of absorbtive material.

Is this for bass trapping? (Contracarpet) Should I put roundies in the corners for bass? I have been looking at "noodles" the long, skinny floatytoys made out of closed-cell foam. They look like they might work.

No, it's more for higher frequency control and diffusion. By varying the wall coverings, you can get a little more control over the character of the room. Personally, I prefer to just put as much absorbtive material on all the walls, and kill as much sound as possible, generating, any 'ambience' or character later in the digital realm. But that's coming from someone who has never had the luxury of large rooms to work with. I would definitly love the oportunity to have a large room in which I could build a great 'sound' into.

Wha??? So they would go OVER the absorption panels? Open for deader, close for live-er sound?

Yes and no. As far as how it will affect 'deadness', opening and closing them would affect mostly higher frequencies. If you left them hinged, you would have some control over adjusting 'diffusion' characteristics, at a much cheaper cost than RPG diffusers and the like.

Do I angle the panes of glass in the window?

I don't think I would worry about that for VO work. Just don't have the speaker talking into the glass. Position him somewhat away from it, with the glass door (which is a door for entering/leaving the booth) at an angle to him, on the side. This way any reflections are likely to first hit an absorbtive wall before bouncing back towards the mic.


Don't forget to pay as much attention to the monitoring room and the monitor equipment too.

As a final note, Couches make good Bass traps, put a nice heavy/overstuffed one in there if you have room.... 8^)