I have a very detailed/"real time" multi page build thread at The IB Cult forum , however I want to post here my finished product for the Master Index of DIY Subwoofer Projects thread.
Since my 12 page build thread at the The IB Cult forum requires login/password, I was asked by "LTD02" to post a thread here, this will be "cliff notes" version of that 1+ year journey.
For those considering IB subs:
Read ThomasW IB FAQ a few times http://home.comcast.net/~infinitelybaffled/index.html
Read ThomasW Generic IB design/build/install a few times http://home.comcast.net/~infinitelyb...Bmanifold.html
Many thanks to ThomasW, Chrisbee, and everyone else @ the IB Cult for their help.
The start of my IB journey:
Quite a while ago, sometime in Summer-2007, I read about IB subs, which started my long odyssey into the DIY speaker mindset and attempting to build a subwoofer.
HT room layout:
This is my first DIY speaker project.
At the IB Cult forum I was able to learn/build/create a neat looking (4) x 15" line array IB subwoofer, with fantastic sound capabilities. 12/21/07 was my 1st build thread post and was a 1 year journey.
I've named this IB subwoofer "Usul", because I had to cut thru rock (concrete foundation wall) to make this project a reality, you'll see that below.
I went from thinking about a Dayton HPSA1000-R 1000W Rackmount Subwoofer Amplifier to power 4 Dayton IB385-8 15" IB Subwoofers; to eventually (4) AE IB15's driving them with the Behringer EP2500 Europower Power Amp, EQ Behringer FBQ2496 Feedback Destroyer.
My total investment is around $1.3k, speakers, amp, EQ, mounting boards, hardware, speaker grille cloth, etc.
-I built a 4 x 15" array, it's backwave vents directly into the utility room. That is closed off from the rec room via sealed door. I did more isolation via 1" styrofoam/sealant at HVAC duct locations.
I was concerned about the bass booming the HVAC ducts, since my GeoThermal system is in the utility room and it has sheetmetal HVAC supply/return main lines entering/exiting the room. If there was a duct boom I thought to add some damping method to that problem area. (like a mastic patch to stiffin the duct/etc). That was not needed.
-The array is vertical and on the RH side of my DIY 130" screen. That is due to practical layout.
-My basement is a engineered foundation, the walls are concrete on outside 3-4 " thick, with 2" foam insuation, there are load bearing concretre "studs" 9" deep on 24" centers, these have 3/4" wood attached to them for hanging drywall. My line array baffle plate was mounted to the foundation wall via threaded rod and lag screws. Very solid/rigid, basically 0 in plane motion unlike other line arrays that mount to stud walls.
Planning/cutting the concrete foundation was the 1st major hurdle.
I consulted with Michigan Superior walls and got the information needed to "cut a interior window" in my foundation wall, this was great news, IB array can directly be mounted and the backwave simply radiate into the utility room. Prior I had "wrong/less desirable" ideas.
Since I have a log home, my roof loads are on the front / back walls transferred there via the ceiling/roof beams, not the side (gable) walls.
The foundation wall I'm "cutting a interior window" is on the gable side of my home, just makes things a little easier.
This just shows a lot of thought/planning/design detail has to go into a project before actual construction starts, and during as you run into "unknowns".
Prep area with plastic sheeting to keep concrete dust in control (gosh there was lots of dust, way more than I figured)
16" x 66" IB sub "window", the concrete stud was a royal PIA to remove, my speaker wires were ran thru 3/4" pre-drilled holes on center, so I had to induce cracks there and remove the concrete stud w/o damaging the wires, and remove the rebar rod, 100% success.
Sub-woofer porn shot 4 AE IB15's, now the fun began.
Did the below last year Sat 5/3/08.
Started with detailed baseline of actual existing construction situation on grid/graph paper:
Made a real size paper template, mounted it to see/confirm/modify design.
>>Full size is much better than some scale drwg, gives a real feel for the mounting/other details.
HT side (line array is mounted on this side). I had to cut 1 3/4" slot for the MDF/OSB plate to fit in for mounting on the RH side.
Before drywall, 4 years ago during the framing phase of the basement/HT, I put a 2 x 4 along the concrete joist via construction adhesive and nails, that is my RH side attach point.
That also means the total thickness from inside the HT room will be that 1 1/2" + 1 1/2" for the OSB/MDF sandwich, so 3" step into the HT room side.
View from utility room side, green shows 2 x 4 pressure treated wood I plan on using to "clamp" the OSB/MDF sandwich tightely against the concrete walls/studs AND control in plane stiffness/flex
Cut both MDF and OSB board to 25 1/4 width, glue and lot's of weight. Spread glue.
Weights and constant wiping of the glue that got squeezed out from the sandwich. I found a flat portion of my garage bonus floor, so sandwich OSB/MDF should be flat. Used some scrap 2 x 4 blocking to hold the slippery sandwich together.
Here is my current mtg plate design:
-brown outline is OSB/MDF sandwich
-Dark green (5) horizontal 1 x 2 structural boards for added in-plane stiffness
-light blue are attach on the HT side, I will use bolts to clamp the front of the mtg plate to the 2 x 4's along both sides
-Light green shows (3) pressure treaded 2 x 4's that will be used to "clamp" sandwich board to utility room concrete wall via threaded rods. I will countersink the MDF so the HT side is flush. My idea is the threaded rod will help clamp the board to the concrete studs AND minimize in-plane flex via nut/washer/lockwasher on each side of the OSB/MDF sandwich and on each side of the utility room side pressure treated wood. First, snug up the threaded rod from both outside areas, then tighten both inside areas.
If need be, after watching the sub in action, I could further stiffen in plane motion for the center portion by a center rod, I'm guessing not needed, but don't know at this time.
-pre-fit mtg plate to area, cut-out 5 clearance notches on RH side for wall stud/wire mtg clearance. Transfer holes/cross bracing locations to both sides of plate, make sure "good to go" and nothing obvious is bad. Take plate to garage, router circles.
Take plate to basement, pre-fit just to check ok.
Take to garage bonus room, cut/glue cross braces on.