Week 120 (Control Room Framing, Part 3)

In construction photos by Michael Tiemann

As I explained in last week’s update, the angles in any control room are unlike any angles one expects to find in normal framing carpentry.  And our Control Room design has more interesting angles than most.  This week we established the endpoints of the most unique framing in the project, the intersection of a sloped front wall meeting angled side walls that both intersect a ceiling that is itself both pitched and rotated.  There is no steel square in the world that tells you how to measure or make those cuts.  In fact, even locating where in space these different planes all intersect is a math problem unto itself.  Here is the solution given in wood:


To learn how we figured this out (and about more construction progress), read on…

Here’s the same picture with some colored dots highlighting the interesting points: purple, red, green, and blue.  If you are color-blind, the purple is the dot where the peak of the control room roof meets the CMU wall, the red dot is the one centered on the header of the interior Control Room window, the green dot is where three framing members intersect at the steel ridge beam of the Control Room roof, and the two blue dots are where two of those framing members run down the planes of the roof and meet at the angled side walls.


As I explained back in December 2009, when all was said and done, the bent steel beam was bolted to the concrete masonry wall within zero eighths of an inch:

This was good because it meant that the Control Room could be built according to plan.  The purple dot represents the precise point where the bottom of the steel beam (hidden by sheetrock in the photo, but visible when the framing measurement was made) contacted the masonry wall.  This intersection of grid line (the exterior wall), the east/west center of the beam and its height gave us the first measurement we would need.

The red dot, a true grid point, tells us the theoretical start of the 45 degree front wall.  The purpose of this sloped front wall is to act as the front membrane of an enormous bass trap.  When low-frequency energy comes out of the monitors and passes by the mix position, it then reflects off the hard floor, off the hard rear wall, and then reflects back up into the cloud and the front bass trap.  As you already know from last week’s report, the front wall is angled at 4 degrees, which means that the actual intersection of the theoretical 45 degree wall with the header over the control room window is “interesting”, but not that difficult to calculate directly.

The green dot is a bit more challenging because it comes at the intersection of two different slopes: the 45 degree front wall going up and the 5:24 pitch of the ridge beam going down.  To calculate this point, one can construction a simulatneous equation of two variables, North-south displacement (which we call x) and height (which we call z).  The point was easily found and marked:


The reason the wood framing members don’t line up perfectly is because though the steel beam is set perfectly, it has a 1/8″ twist along its length.  The wood members thus straighten out the shape of the room inside the control room (which is all that matters).

But the real challenge and the real fun was figuring out where the 45 degree wall met both the angled side wall and the ceiling.  Those “magic points” are shown in blue, but how did we get there?  Well, here’s the math:

Or something like that.  Needless to say, once we knew where to put our plates, the rest of the framing becomes a relatively straightforward exercise of placing framing members on 2′ centers.  And you thought Pre-Calculus was a waste of time!

But of course that’s not all that’s going on right now.  The Annex is being prepared for several large concrete pours.  The final plastic is in place, and the area of each dammed (not damned!) area is clearly visible so that the concrete folks know how much concrete to pour, how much coloring agent to use, and how many crew are needed to do all the hand-troweling work before the concrete sets up.  Here you can see the measurements for half the garage (445 sq ft) and the Machine Room (152 sq ft):


You can also see the vertical lines denoting the points where the grid lines intersect the inner wythe of the Annex.  The Annex Control Room requires a pour to fill 519 sq ft:


I estimate that thick walls and bass traps will eat up more than 80 sq ft of that original measurement.  But our goal is a great sounding control room, not the largest one we can squeeze from our floorplan.

Moving to the outside we can see that the lower soffit of the main building has been finished, including all the boards in the Loggia:


Our hydronics are now hooked up, and we are cooking with gas:


On the inside of the building, more of our light fixtures are being placed into our soffits.  Sadly, one of the facts of the design is that groovy places to put lights are also great places for structural members to travel.  Here we had to interrupt the sub-fascia LVL before it got to the wall plate so that a light fixture would fit.  We made up for that by placing an additional three rafters to or near the corner:


The masons built the concrete block base for holding our massive Dynaudio M4S monitors.  These concrete bases will be finished with a mounting surface that will provide the 4 degree slope angled at 30º in from 90º:


Finally, the electricians have begun working on the Variac panel in Sound Lock 2:


All good stuff, and more to come…