Johns Standard Control Room

Better than a wall wart :wink:

Greetings, We're rockin' on the sheetrock. (See photos below) Attached is a sketchup file of the inner shell to final finished dimensions within 1/4 inch. Note the supply air duct is in the upper left corner. (return air exists but not shown in sketchup) What acoustic treatment do you envision for this size and shape room? I know I've seen a room this shape somewhere before, but I can't find out what they did for treatment. I was planning on incorporating a large wall unit in the back of the room for storage, diffusion, absorption, possibly with built in bass traps. This would be a custom built unit, that comes apart for moving (see Recording Magazine, May 2010, article by Brian Gadson) I could make this wall unit narrower than the room and leave room for bass traps in the rear corners. The main question is: do you think the front corners will be needed for treatment? I ask because if a soffit is required across the top of the front wall, I'd better remove the boot now and install a coupler in the wall before the sheetrock is finished. But the need for an air vent/soffit is the urgent question at hand. Enjoy the photos.

you were just going with speakers on the stands? also, i see a single vent, you should have two - a supply and a return. were you thinking a soffit for the duct in the room or a baffle box outside the room and put the ducts in the front and back treatment walls?

gullfo wrote:

you were just going with speakers on the stands? also, i see a single vent, you should have two - a supply and a return. were you thinking a soffit for the duct in the room or a baffle box outside the room and put the ducts in the front and back treatment walls?

I thought I start with speakers on stands and maybe build the "component" type setup later. Planning on baffle boxes outside the room. (updated .skp file below with return duct added) There is a return, I forgot to put it in sketchup drawing.

Just to clarify the term "wall unit", I meant some custom made or modified furniture similar to this, placed along the back wall. The shelves could be filled with books, software boxes, DVD, CD's and other items for diffusion. The upper sections could contain bass traps and other types of membrane panel absorbers. The lower cabinets could have louvered doors (or not) and store the messy bits. These "wall units" could go across the entire back wall, or you could leave enough room for larger corner traps. So back to the question about treatment options and the front of the room.... Can I leave the supply air in the wall where it is? Or should I plan on building a soffit in case I need to accomodate front corner traps? Ideas? (The idea was in an article by Brian Gadson in May 2010 Recording Magazine which is not available, (no link) unless you purchase it on-line). (Not the actual wall unit)

the only concern then is the closeness of the door to the front wall - your space in that corner is limited. stand-wise it shouldn't be a problem. the furniture probably will work although not as effective as a proper diffuser - angled slats, QRD, PRS, poly, etc etc

gullfo wrote:

the only concern then is the closeness of the door to the front wall

Can you elaborate a little on this concern and what it means? I assume the vent in the upper corner is OK?

the door is close to the front wall - so if you wanted to put a soffit in there, it would be very tight because it's only about 16" or so.

Gotcha. So I'll deal with speakers on stands. Less work, done sooner, then I can get back to music sooner! The first layer of sheetrock is done except for that front corner. I'll do that tommorow along with caulking, tape and mud. More pictures when I'm too tired to hold tools. Thanks for all your help Glenn! PS: How do you find time to answer so many questions from so many different people? You must have mastered not only space, but time....

are u taking any kinds of measures so the PVC piping wont become a flanking path between rooms, or the main structure?

takman wrote:

are u taking any kinds of measures so the PVC piping wont become a flanking path between rooms, or the main structure?

Takman, I took a look at that pipe again and It IS only clamped to the back side of the inner floating wall with soft rubber cushions, around the pipe at each clamp/stud mounting location. So I think it's OK. I just stuck a piece of soft rubber around the output side, to remind me to isolate the PVC conduit from the outer wall sheetrock when I start doing that next week. Thanks for looking after me. Much appreciated.

Since you did not choose to decouple the ceiling, why did you fur it down and lose more height while adding more rigidity?

xSpace wrote:

Since you did not choose to decouple the ceiling, why did you fur it down and lose more height while adding more rigidity?

Ignorance probably. It seemed a lot easier than adding blocking between every joist to support the edges and we thought it would add strength to hold all that rock up.

JohnH wrote:

takman wrote:

are u taking any kinds of measures so the PVC piping wont become a flanking path between rooms, or the main structure?

Takman, I took a look at that pipe again and It IS only clamped to the back side of the inner floating wall with soft rubber cushions, around the pipe at each clamp/stud mounting location. So I think it's OK. I just stuck a piece of soft rubber around the output side, to remind me to isolate the PVC conduit from the outer wall sheetrock when I start doing that next week. Thanks for looking after me. Much appreciated.

no problem 8) another question....are you sure that the PVC piping is large enough? not based off experience, but from reading other threads. I cant remember what thread it was.....but they went to put the wires thru, and realized that the piping was not large enough and couldn't get the wires to go thru. It was the 90 degree bends that were the problem, not the straight runs. luckily they caught it before they finished running the pipes.... just a thought anyways...keep up the good work :mrgreen:

takman wrote:

another question....are you sure that the PVC piping is large enough?

It's 1.25 inch. I probably should have gone larger. The sheet rock is up on the inner walls. I could change it still, but probably will leave it. I wonder if there's a chart for maximum number of audio cables in conduit by type and size somewhere? Maybe it would be easy to fit (1) one, Multi-pair audio cable like an "8-Pair Mic/Line" cable in there, rather than a bunch of individual cables. Also there is a lubricant for snaking wires. And if all else fails, my floor is still unfinished and open below so I could always add a huge conduit down there. I'll keep it in mind.

Well if you divide the conduit section (area of circle Πr² of inside) by the cross-section of the cable (not the gauge!) that will give you a rough idea. There's a reduction factor to account for wasted space but if you calculate for a couple of cables less it'll probably work. (If you have a vernier caliper you can get the diameters fast) As for snaking the wires, make your life easier, get a cable puller. The ones made of nylon with a metal feeler are pretty cheap, or maybe you could borrow one.

if you run some strong thin rope as you assembly the conduit and leave enough to pull it back and forth, pulling the cables through is pretty fast and you can re-use it later.

Thanks for the tips guys! I've finished the backer rod, caulk, mud and tape on the first layer of wall board on the inner shell today including a 2nd coat of mud. No need to tape the corners until the final layer right? Its interesting acoustics in there right now. No obvious single notes but the expected reverberant sound.

tape on the last layer. backer rod and caulk in between staggered layers.

gullfo wrote:

tape on the last layer. backer rod and caulk in between staggered layers.

Great! You ever bother to use any of those visco-elastic compounds between the sheets? (sounds kinky) Wondering whether to push on with the 2nd layer of wallboard or slime it up.

Here's a few photos. 1st layer of wall board, caulked mudded and taped. Rear Front right Front left

Green Glue and Quiet Glue have their uses and in this case, it might be worthwhile to do so. Ted White's company sells Green Glue and is a regular contributor here. there has also been quite a bit of discussion on Quiet Glue which appears to have substantially similar properties and has some references to lower cost but its really up to the distributor you work with to finalize the costs.

I just ordered a 5 gallon bucket of green goop and a dispensing gun. I shopped around and found substantial discounts. From my vibration analysis days, I well understand structural vibrations, resonance and damping. This non-hardening, "snot like" material fits the bill as a "shock absorber", "damping pot", vibration to heat converter. Though the frugal bastard in me wanted to make my own 'cause it still seems TOO expensive. So I seriously considered mixing up some Poly Vinyl Alcohol, water, borax and green food coloring to make make my own green slime, but it would probably grow moldy and then dry out. So after too much research...official green goo it is. Like the star ground wires, you can't add em later. Also sounds like it will be useful for a damped floor sandwich as well. As we've discussed, the floor will be the final weak link. I've yet to take any sound readings (my bad). Very little traffic this past winter except early in the AM before I am out of bed. I will try to set up Audacity on a sound activated recording mode. Do some comparisons of the result of all this construction.

Progress Report First off, thank you Glenn for calling my room an "awesome control room" in protechtor's thread. I am humbly and undeservedly honored. I do hope it will be awesome. I'm still here....still working. I'd post a picture but it would look exactly the same as before. Except the room is another one and one quarter inches smaller in length and width and 5/8 of an inch lower (the second layer of gypsum...wallboard...sheetrock is installed). So scroll back up a few posts and look at the progress. Its a bit anti-climactic and a lot like deja vu...all this labor and the room looks exactly the same, and the walls are closing in on me :shock: The green glue was interesting to apply. The viscosity was lower than expected but it did not run. I watched the on-line video beforehand and it was easy. Though I am not impressed yet with the damping effect (impact test using fist) I'll go punch the walls again in a few weeks after it reaches optimal cure point (30 days) I left some scraps out with the stuff on it to compare. The perimeters have been dutifully and meticulously filled with backer rod and caulking, still leaving an undercut to allow for mud (wallboard compound) and tape. I went big bucks ($6) and bought the large roll of fiberglass mesh tape for the seams to avoid crackage later on. The past week has been spent applying the tape and multiple layers of mud over the joints and screws, lightly sanding in between. I'm starting to plan my broadband absorbers and searching for some 703 or equivalent locally. Other than that, it's back to the mud and the dust :evil:

sorry the walls are closing in on you... it wil be much worse soon when its all "dead" from the treatments :mrgreen: :twisted: