Enter the Headbanger (Part 1)

It seems like the scope of Hapy's interior grows every week. I was just going to do a sound-containment effort, and it has grown in all directions almost from the jump. Today, I visit the furthest end of the sound system: the rear speakers. This little project actually took a few weeks to do, and this post got super long, so I split it into two. I will post the other half once I complete the work. Ha! Apologies for no post last week. I had spent the prior week visiting my son T in Los Angeles, and got back the Monday night before. Before I begin, Hapy Birthday Emily (my sister back East)!

How Did We Get Here?

headbanger from a 1976

So, I'm hanging out with Hapy, thinking about what to do next on the sound deadening one weekend morning and it occurred to me that if I were ever to want speakers overhead in the back of the bus, now was the time to wire them. Once the sound deadener is all the way in, snaking more wires will be much more difficult. While looking around at the furthest back part of the rear ceiling, I remembered that both the original Westfalia and the 1979 had a shelf or headbanger cabinet covering up the rear tailgate torsion springs. So, what had started as a "let's just run some wire" became "let's add a shelf/cabinet thing to hold speakers and cover up that rear-end ugly". More evidence that this bus will never be finished. I actually like that thought, but I'm weird.

Rear Speakers

speaker boxes

Recall, my earlier version of the rear speakers included a pair of speakers that basically floated around. When we were parked, we could move them out the slider for music under the canopy. I did not want to lose that capability, but felt that adding a pair of semi-fixed speakers back in the sleeping area would help the sound because we could actually dial-in our on-the-road sound based on those fixed speaker locations. I ordered a pair of Rockford Fosgate 6x9 speakers and a boom-mat from Crutchfield with a plan to flush-fit them into the lower ceiling, but.... ultimately, I simply could not bring myself to cut 2 big oval holes into the bus. I thought about a pair of 6x9 speaker pods from the guy who supplied the pods for Oliver a few years ago. Those were okay, but the 6x9 options seemed really big, and hung down over 4 inches. I found a speaker box that is curved on the back instead (picture on the right, here). I felt that these would give me more options for targeting the sound and they are quite small. The white lettering is absolutely atrocious, so I literally shot them with black spray-paint to cover it. If I could have gotten these boxes without carpet, I would have preferred that. I intend to cover them with headliner, because, while the spray paint removed the shocking white, the stitched letters are still visible. Wow, so ugly... but they will do the job.

The wiring for these speakers followed the line that the rear defroster wire takes: up the passenger-side A-pillar, and inside the lip along the ceiling. Behind the rear slider, they followed the course along the passenger-side ceiling.

 

Positioning and Modeling

rubber-strap thinking

I started thinking through options for how these speakers could integrate with the roundy rear end by hanging a speaker with rubber straps from the tail gate torsion springs. There is a support that runs from the lower ceiling back to the inner edge of the spring hinge on both sides. I used those supports as my outer edge fixed point. With a speaker in place, I checked the rear-view mirror. I tweaked the angle and tried again. I wanted the top edge to be within an inch of the ceiling, but did not want the lower edge to block too much of my visibility. I arrived at a viable compromise with the outer top-edge of the speaker sitting about 1/2" below the ceiling. Surprisingly, this "compromise spot" set the speaker fairly close to 45*.  This location would remove the top inch or so from the rear glass when looking through the rear view mirror. Based on the picture above, this is more than what is lost on the later bay-window Westfalia when the headbanger cabinet is installed. Can I see out the back? Yes. Will I be able to see out the back when it is packed with stuff? Of course not, but this cabinet is not the difference-maker; my packing ability is. Movin' on, the biggest difference in having this cabinet will be when I try to get in/out of the rear hatch or lean over the open engine access hatch. When I do either of those, I will be reminded why we call these cabinets headbangers.

With the position set, I shifted to solving for mounting. I started with some thin cardboard out of the recycling (surprise: I used a 12-pack box), measuring, cutting and fitting. This was not especially fruitful until I started marking up locations on the ceiling: inner edge of both speakers, and the center point both on the lower ceiling as well as on the upper lip of the tail gate. Now, with more reliable measurements,  I could determine a viable model. I planned for a shelf to run along the entire bottom, from outer speaker edge to outer speaker edge: 37" long, but only 5" deep. To help make the model better, I simply cut a 37x5 rectangle out of the remaining OSB from when I made the front shelf (See New Cab Shelf). With that shelf in hand, I modeled the supports with thicker cardboard. 

support modeled

The rear edge of the shelf required a 4" tall support. From the front edge of the shelf, the support will climb at a 45* angle. The supports on the ends will meet the ceiling directly. The 2 center supports, however, required an additional 2.5" of straight vertical to reach the ceiling, due to the curvy nature of the ceiling. The rear contour of the supports angle from the 4" drop up to 6.5" at the front (on the end supports) of the shelf before running straight forward. A few inches forward of the point where the lower line angles upward, the middle supports run straight up another 2.5" before running straight forward. The image on the right, here, shows the modeled shapes. I tested these with the OSB shelf, placing the cardboard on the spots I marked for where the speaker ends will be. Things looked good 'nuf.

From Cardboard to OSB

I took these cardboard cut-outs and applied them to the cut-up OSB, making 4 supports to go with the bottom shelf. After some fun with the jig-saw, I had 4 supports. This effectively used the remaining OSB, but I had enough to make the structure. Consider, between each of the outer and each inner supports, a speaker box will get mounted. Between the inner supports, I have an opportunity. My plan is to mount a pair of USB charger ports, another shelf and then enclose whatever is left. Since I am out of OSB, I will look to other materials I have lying around. Ultimately, the angled front face will get covered with headliner material, allowing it to at least visually integrate into the ceiling, and cover up the simply awful lettering on the speakers while I'm at it. Win!

glue-in the supports

Onto the base shelf, I drew the lines for where the supports were to be attached and confirmed again that the speakers would fit between. Then, I took the shelf and one-each of the supports and sorta-kinda test fit into the bus (keeping 3 pieces of wood held consistent with 2 hands is tricky). I felt satisfied that the lines, spaces and supports matched up with where I intended them to land, but, again, it's hard juggling 3 pieces of wood. When I built the speaker box for Oliver (See need reference), I learned that the screws were really not the key to making a solid box. The screws simply held the parts together while the carpenter's glue sets. Knowing this, I did not bother with screws at all; I used large clamps. Since I only have 2 large clamps, I did 1 support at a time: apply glue to both sides, set the support in place and then clamp both ends of the shelf overnight. The picture on the right here shows the last support getting glued in. Yes, that is one of those US General tool cabinets I posted about (See $50 Tool Chest) and that is Oliver in the background patiently waiting for dry weather and a trip to get smog certified.

 

More Planning

OSB supports

Now in one piece, I could plan for the USB chargers and such. I figure that the chargers are 2-1/4 inches in diameter, and we will need about a half an inch underneath it to snap-off the cover. To retain symmetry, I planned for a half-inch above, so I rounded up, making the USB face 3-1/2 inches tall. Because of the angle, I figured that the USB chargers would go on the lowest spot, since they take up the least amount of space. Above the chargers, I will put a shelf for setting the things that are getting charged (phones), and, again, because of the angle, the shelf being 3-1/2 inches up from the bottom will increase the depth of the shelf enough for a phone to fit without hanging off the edge, but only barely. The shelf doesn't really need a top, but to clean up the leading edge of the cabinet, I planned for a short drop front which I will cover with headliner. For materials, I have scrap bits of Oriented Strand Board (OSB) to make mounting points for the various flat surfaces. For the flats, I have one of the 1979 Westfalia panels I can cut up. Yes, I could save that for someone, and I could go find some veneer of some kind. But, this is free, and on-hand.

Some Assembly

I drew my plan onto the supports, and cut up a small pile (6) of OSB supports. With my limited number of clamps and vice-grips, I had to follow a similar pattern as I did with the supports: glue as many as I could support with what I have on hand and then wait a day. I oriented the 6 bits to support the USB charger ports and the small shelf directly above.

speaker prep

I then shifted to the speaker boxes. First, I prepared the boxes for speakers to get installed. I set a speaker and corresponding grill into the hole, marked and then drilled out the 4 holes. I set the speakers aside and returned to getting the boxes attached to the cabinet. These boxes deliver with wiring cups already glued in, but the location of the supports will completely hide them. I thought about boring holes in the supports, but decided instead to cut a small channel out of the speaker boxes and run the wire into that gap between the support and box. Then, I drilled 4 holes for each speaker, 2 per support, about 1/4" in from the long diagonal edge. Holding the speaker box in position, I drilled marks into the speaker box fabric, pulled the box aside and then completed the bore. I then returned the box to the cabinet and sent 1-1/4" long wood screws in to hold the speaker boxes in place.

 

For the shelf and USB charger surface, I measured out and cut with a razorblade the rectangular shapes. Into the USB charger surface, I bored 2 2-1/4" holes for the USB charger ports with a hole-saw bit on my drill.

Wire It Up

At this point, the weather outside was frightful. I wanted to take the cabinet out to Hapy to test fit, but I wanted no part of the wind/sleet/rain mix that was going on (it has been an interesting, albeit cold and wet, Spring in the Pacific NorthWest). I worked through the speaker wiring instead. We like the versatility that the plug-in speakers offer so, I added 2 plug-ports on the right rear edge of the cabinet. We will be able to add rear-facing sound our the rear hatch simply by moving the remote 6x9's. You can just see the rough-in plugs in the lower right corner of the picture below.

 

rough speaker wiring

Last, I wanted an ability to turn off the rear speakers from the back, without turning the whole system off. I figured, if there were a point where one of us wanted to take a nap, but the other was just hanging out under the canopy, the under-canopy person may still want some sounds. To resolve, we will fade the speakers to the rear, so the floating speakers still get signal, and then turn off the overheads. How? I added a STDP (single toggle/throw, double-post) switch. I wired the ground/negative-side of each speaker wire through the switch, and planned for the switch between the USB chargers (1/2" hole). The ports and the switch significantly increased the wiring complexity, but once completed, we have 2 plugs ready to plug into the speaker wires in the ceiling, a pair of fixed speakers overhead, a pair of ports for the floating speakers, and an override switch to turn off the sound signals passing into the cabinet.

 

I am going to stop here. Partly because this post has already gotten super long, partly because I have already spent a couple of weeks on this (and I post weekly), and partly because this is as far as I have gotten. I will complete the assembly, cover parts of it with trunk carpet, cover other parts with headliner and then get the cabinet installed/wired into Hapy. When I get all that done, I'll write and post "part 2". Maybe the weather will improve by then.

Thanks, as always, for following along-