Returning to Hapy Sounds - Part 1

In the midst of the Summer 2019, I added the ability to listen to music to Hapy, the 1972 TDI-powered microbus (See Making Hapy Sounds Part 2, for example). Today, I start my revisit with the front speakers. In this part of the front speaker improvement, I create very very small speaker boxes for a pair of 5-1/4" speakers with materials readily available at the hardware store; remove the speakers from the door cards and mount them into those speaker boxes; and last, get it all into the bus. Unlike most of my posts, the overwhelming majority of the measurements are in inches rather than mm. This is because here in the US, all of the published material about speakers is in inches. So, any information I put here can be more easily cross-referenced.

Why?

Diablo Royale pod

I guess it makes sense to start with answering the question "why are you making a change". There are a couple of reasons. First, the door cards that I made out of pressed cardboard are starting to fail. Unlike the original cards, the material I used was not designed for this purpose. So, over time, as some moisture appeared (this is the Pacific NorthWest, after all), the cards started to bend, and pull away from the doors. With the 5-1/2" speakers mounted in the lower part of the card, the card condition deteriorated more quickly as the speaker added a swing-weight whenever the door was opened or closed. So, when the door was closed, the bottom of the card (and the speaker) were not mated to the door, allowing the speaker to kind of hang in space a little bit.

I decided to replace the pressed cardboard cards with a laser-cut PVC set from WerksBerg. These precision-cut PVC cards are great, and many options are available, but a pre-cut hole for speakers is not one of them. I decided that I didn't really want to cut the PVC. This leads to our second reason: while the sound was okay, it wasn't awesome and maybe it could be better while driving. The only real upside to the speakers being in the doors was the added sound we got in the music festival camping lot when we opened the passenger door. When driving around, there was music, but it lacked some clarity. Of course, the road, engine and wind noise contributed, but that's another whole story... and solution path for another day. I think speakers just hanging in space (back not enclosed) negatively impacted the quality of the sound, and the cards were not going to last much longer.

Options

schedule 40 4" cap

So, if the speakers are not going to be in the door, what other options are there? There are a few. Some folks cut holes in the toe kick. This brings the advantage of having speakers facing you, but they are still down by your feet. Some bus owners replace the little fresh air vents with little speakers. This option moves the sound closer to your ears, which is great, but you lose those vents, and the only speakers that fit in there are super small (like 2" tweeters).

If you have a parcel shelf under the dash, you can set/mount speakers in boxes placed on the shelf. The shelf narrows on the outer edges, so speakers most likely fit best near the center of the bus, near the central air pipe. I don't have those shelves, but even near the center they do not look terribly deep. When I first bought Hapy, a prior owner (PO) had mounted small boxed speakers to the big metal air vent boxes. They didn't work, and the PO had taken the stereo with him so I pitched those speakers. Of these options, I do prefer rear-facing / under-the-dash locations over the door cards. The trick will be figuring out how to mount them, and exactly where they will provide sound best.

5-1/4" Thinking

test fitting 5-1/4 speaker

So, we start with figuring out a way to mount / hang speakers under the dash such that they won't get damaged yet they fling sound towards us. The 5-1/4" round speakers I have are kinda large for the space. Sure, 6-1/2" round speakers are bigger, and more common, so finding a speaker box or pod that fits the 6.5 is definitely easier. Still, I have the 5-1/4's and the smaller footprint will play to my advantage now, since the new location will be inside the cab, potentially near our knees.

Ever seeking cheap, yet effective, solutions, I constructed one. But, of course, not without checking out off-the-shelf options:

• There is a guy (Diablo Royale) on eBay who makes plastic speaker pods in Texas. I bought a pair of his mounting pods for Oliver so I could mount the front speakers down by our feet, against the outer walls (See MGB Interior Panels - Part 1 or better yet MGB Gets Sound - Part 1). Diablo Royale had pods that fit 5-1/4" speakers, but they were still open-backed, $50US per pair and at least 6 inches across at the top by 4 inches deep. The base was at least 7 inches across. Looking at the under-dash, that would have been pretty ugly. Without a flush backwall, which would be nearly impossible with the contours up there, the sound would not throw as well. To make them fully enclosed / flush, I would have to construct a rear side.
• There are MDF speaker boxes, wrapped in trunk carpet. These are also larger, but at least they have a back. The smallest ones I saw for the 5-1/4" round speaker were 8 inches square (or larger as rectangles) and 5 inches deep. If I had a parcel shelf, they might fit, but really only in the center since those parcel shelves get shallow as these near the door A-pillar.

better view of a
metal bracket attempt

Those are basically your off-the-shelf options. For the space we are targeting, they are not terribly good. So, we get out of the (speaker) box, and see what we can come up with. Our requirements are few: the speaker requires a 4-1/2" hole to sit into -and- it needs just under 2 inches (1-13/16 inches) from the mounting surface to the rear of the "box" for the cone and magnet.

It turns out that a 4" schedule 40 PVC pipe cap is a great starting point for a speaker pod. The one I found is 2 inches deep from lip to rear wall, but I saw deeper ones on the 'net. The inner diameter is 4-1/2 inches. I know; you're asking "but you said 4 inch cap". Yes, that's right. The schedule 40 4" cap refers to the industry standard 4" pipe, which is an approximation of the inner diameter of the pipe. Since the cap goes around the outside of that pipe, there is additional diameter to account for the thickness of a schedule 40 PVC pipe (here's a link for more dimensions). Neat, eh? Oh, and these are about 1/2 the price of the Diablo Royale pods at less than $15US each, made-in-USA, they are available at your local hardware store -and- they have a back wall.

5-1/4" Speaker to Cap

Once in hand, we need to figure out how to mount the speaker to it, and then how to mount the unit into the bus. I started with the second question first by moving the speakers around while playing the stereo. I concluded that the farther to the outside I could put the speaker, the better the overall sound. I resolved with placement directly below the dash vents. To mount, I bore a pair of holes through the cap, and mounted the cap/pod to the metal vent cover. Since the vent cover could be removed and replaced, I could use bolt/nut /washer fasteners instead of self-tapping or sheet metal screws. I think the nut-bolt combination creates a better, more reliable attachment.

plastic mounting tabs

For mounting the speaker to the cap/pod, I started with the smallest angle brackets I could find at the local Ace hardware store (3/4") when I got the caps. I also tried 1/2" brackets but they were no better. I probably could have super-glued something plastic, but that seemed flimsy. After a lot of drilling, cutting measuring and more cutting, I abandoned the 3/4" angles. I tried 1/2" angles, but they did not line up right with the speaker cover holes. I bought a set of angles online that had a channel, but even the smallest set like these were too large. I even tried constructing mounts with some scrap wood (1/2" wide and thick by 3/4" tall), but they were too bulky.

 

So, how did I resolve it? In true ghetto style, of course. While cleaning up my garage, I found a lid for one of those larger rectangular plastic storage tubs. The lip bent around 90* and extended about 3/4". With tin snips, I cut a series of pieces out, each about 1/2" wide and at least 1/2" into the top of the lid. This produced 8 little plastic "L" shapes to construct mounts out of. I marked and drilled holes, and then cut away the excess material with the snips. They are barely visible now, and once I wrap the pods with trunk carpet of some other fabric, they will mostly disappear.

 

5-1/4" Pod Wiring

With the physical mounting solved, I turned to wire routing. Ideally, I would have included a wiring cup. I omitted it because the flat bottom of the cap/pod will be pressed against the bus for mounting. Then, I thought about putting a cup on the side. I figured between the curvature and the shallow space within, it simply wouldn't work. So, instead, I drilled a small hole in the side of the cap/pod, and sent the pair of speaker wires through it. Leaving some slack in the wires within the cap/pod, I applied a blob of caulk into the hole to seal it back up.

Polyfill?

polyfill'd

My last step was adding some polyfill into the cap/pod. Simply, polyfill interrupts the sound wave moving on the back-side of the speaker when sound is produced by the cone. This interruption improves the projected sound out of the front of the speaker, and tricks the speaker into acting like it is in a larger enclosure: so, more bass. Using polyfill (or not) is kind of a religion with audio folks. I figure speaker enclosure manufacturers wouldn't use it if it didn't do something beneficial, and the 6x9 boxes I got for Hapy's rear speakers were polyfill'd. This cap/pod thing is super small for this speaker, so if it was going to do anything for a small speaker, this is the kind of scenario where it might. Still, the probability that I would really notice is virtually 0 (especially in the while-driving din), but I did it anyway. Ultimately, this cap/pod is about creating a safe means of mounting the speaker, with a hope that the sound is improved through it's proximity to the listener. The sound could not be measurably worse by moving it a foot closer in an enclosed cap/pod -versus- hanging in a loose, flapping door card down by your feet. Quite the opposite, I think it is much better. At least, it is set up to be.

isolation foam

When I get around to making the interior nicer with carpet and other fabrics, I will cover the cap/pods with whatever material I am otherwise using along that front wall so they visually disappear. Or, I'll simply cover them with trunk carpet. Before final assembly, I put some closed cell foam between the speaker cap/pod and the vent cover I mounted it to. This should help isolate the sound / vibrations a little bit. You can see the foam in the picture on the right as well as the markings I made to get the speaker aligned for drilling the mounting holes. Last, I simply plugged the wires into the speakers, set the speaker into the cap/pod, set the grill atop and attached it to the brackets. I took the assembly out to the bus and simply re-attached the vent covers with the speakers attached. The wires dangling from the cup/pods were tied into the existing front speaker wires that used to be in the doors, and then tucked away. I may apply a wire wrap to disguise them a little better, but I think they look good enough for now.

Testing

wired up and fired up

Because of my lack of a warm workspace where the bus fits, and a young puppy who can't be out in the cold for more than 15 minutes at a time, I still have not completed the install of the replacement seats. So, testing consisted of playing the stereo without moving the bus. Still, I think moving the 5-1/4" speakers made a difference. Considering that our legs no longer interrupt the sound waves, the speakers are about a foot closer to our ears, and the speakers are contained, there should be some benefit. Ultimately, I probably didn't need to move the 5-1/4's for sound improvement. It is absolutely possible that the open space behind the speaker in the door cavity actually helps the lower frequency sound form better. But, I didn't want to cut the new cards and this was kinda fun, and this was something I could mostly do in a warm garage, with a puppy underfoot.

That's it for today. thanks, as always, for following along-

Handling the Handling (Rear Anti-Roll Bar)

Today, I return from a break with a one-off posting. I remain distracted with non-post-worthy stuff, but I did this work on the bus recently, so I thought I'd post about it. This post covers my reasoning and efforts to install a rear anti-roll bar (called a sway-bar in the US). I could regale you with all kinds of scientific study and test drives leading me to doing this. The reality is, I bought the EMPI kit last Summer ($180US delivered) and it has been sitting in a somewhat large box in my somewhat small garage since. In a way, I installed it because I needed the room. I mean, we just can't keep tripping over, or piling things on, this box, besides I paid $180 for it. That's not a small sum to just not use.

Where Were We

Recall the drive to Leisureland (See Leisureland Road Report) and the drive to/from 4Peaks in the Summer of 2021 (See 4Peaks 2021 Road Report). The wind and passing trucks buffeted the bus, making handling extremely difficult. I had to slow way down on the drive east through the central Oregon desert simply because I could not keep the bus under reliable control. That was scary. I started with the simple: stiffen the adjustable shocks (See Handling the Handling - Shock Adjustment). This helped, but on our next drive out the US-26 for Hapy's birthday, the passing trucks and crosswind still impacted the handling. Consider this quote from that test drive: "he held the road. I needed both hands on the wheel, but it was not (a) white-knuckle experience." <- that is not exactly the description of a solid, love-this-handling suspension that you would want to take for long trips.

I want to see if I could make it better... besides, I have the kit, I need the room on my garage floor and after two months I really need to get my hands on a car with some tools.

Rear Anti-Roll / Sway Bar

CIP1 image has the
bar upside down

Back when I first considered the handling issue, thought through the causes, and was performing my research, I found some other bus owners with similar wind-sheer challenges. These folks were posting on threads talking about the pro/con of a rear anti-roll (sway) bar. RAtwell conducted experiments a few years ago, and most feedback on the interweb is consistent with his findings: the rear bar is great on highways, in windy conditions, going mostly straight, especially when you are burdened with some weight (like camping equipment). Sounds spot-on for my issue, right? Well, there are no upsides without downsides.

For these bars, the downsides include a tendency for over steer (vehicle turns more than turn of steering wheel would imply) while cornering, especially in city driving, and the rear suspension is not as independent so you will feel more bumps. So.. the bar is great on long trips, but around town, where there are speed bumps, sharp turns and potholes, they may make things worse. One point that I found especially interesting is where the long road trip meets city driving: freeway off-ramps. Since you are often pairing rapid deceleration with an increasingly sharp turn, the influence of the rear bar could come into play. This feedback, however, is the opposite of what both CIP1 and EMPI says about these bars. Taken from the CIP1 site: "...These sway bars provide the handling demanded by the enthusiast driver. They help to control body sway and help road adhesion under hard cornering...".

clean rear bar example

So, what about installing a bar and just disconnecting it when you're not doing the loaded-on-the-highway thing? I thought about that. The Jeep and off-road crowd will disconnect one or both anti-roll bars when they go crawling. The fancy new ones allow you to do it from the driver seat with a button. Old-skool involves rolling under your rig and disconnecting the ends, and zip-tying it out of the way. On an old bus, there obviously is not a push-button install option. The bar, however, is not a simple straight bar either. As you can see from the picture on the right, here, that I nabbed from "Goodhand77" who posted it on theSamba, it runs from the mount points at the wheels forward (front is front) and inward to the frame rails. It then dips in the center to create space around the transaxle. So, if you were to disconnect the ends and try to rotate the bar up, the lower center section would rotate up towards the transaxle. More importantly, it approaches the suspension arms. If you just disconnect the ends and let it hang there, it may interfere with the wheel movement. So that doesn't seem like a safe option. In the end, I concluded that the rear sway bar is an either/or: either it is installed or it is sitting in your garage. I got one last Summer and have tried the sitting in your garage option. The handling was unaffected, but the room in my garage was and is, with no value back. So, we're installing it.

Rear Shock Mount Tie-In

instructions

This is the fun part, when we get to put hands on bus. The install is not mentally difficult, but does require boring 4 holes into your beloved, and it can be time-consuming. I have attached an image of the install instructions. The directions start with putting your bus up on ramps (not stands) so you have more room while the suspension is under standard load. They suggest suspending the bar temporarily while you install it, but I didn't. I just let it rest on the ground while I did the rear connections. We remove the lower bolts on the rear shocks, add an "L" bracket, and thread the nut back through. I thought about reversing the bolt so it pointed inwards, but decided that the VW engineers probably had it like this for a reason. Still, when I want to adjust the shocks, it will be a hassle. Into the "L" bracket goes a bolt with a series of bushings and washers, with the bar and the nut completing what looks like a hardware version of a Dagwood sandwich. The bolt through the middle is barely long enough to make the reach, so I had to compress the sandwich while getting the nut to catch a thread. One side was, of course, harder than the other. Slightly longer bolts (provided are 5-1/4") would have saved me an hour of wrestling with the Dagwood, with washer and nut sent flying with each failed attempt. Once the threading caught, I snugged the sandwich together with a few turns on the ratchet: just enough to set the stack and the locknut plastic, without compressing the bushings at all.

 

Frame Mount

p-side frame mount

With the bar connected at the ends, the frame mounts can be test-fit, marked, drilled and mounted. While test-fitting, verify the marked holes with the size of the u-bolt; since these holes are for the u-bolt to go through, this is super-important. I hit the center-points of the marked holes with a hammer and drift so the drill-bit wouldn't wander. My drill bits are getting worn, so the cutting of the holes took many cycles of progressively larger bits to reach the 3/8" target. Once bored out to 3/8", I set the bar up in place and could tell that the inner lip of the frame was going to prevent the bar from mounting flush, so I removed a curved section of the lip with my angle grinder to allow the bar (with the mounting plate in place) to rest against the flat part of the frame. The instructions mention filing, but it would take all day with a file. I shot the area with a quick pass of spray paint to prevent rust. Finally, we're ready to thread the u-bolt through. This is just an exercise in patience, unless one set of holes was not distanced correctly. Fortunately, my triple-checking during the measure-mark step avoided an issue here. The instructions say to put one nut on and to thread the u-bolt through. The nut is to prevent you from losing the u-bolt into the frame. Because of the tight tolerance, the nut needs to be near the tip of the u-bolt, but then it could fall off... leading to the u-bolt disappearing into the frame. Yep, this happened to me on the driver side, but I was able to coax it out with a thin-bladed screwdriver... and more patience.

Tighten Up

rear anti-roll bar installed

Once the u-bolts are dangled down from the frame, use one nut on the u-bolt as you work part of the mount on the other, starting with the base plate. Carefully, push the bar up and then wiggle the u-bolt through the clamp. Once both bolts are through , the nuts are threaded on, tighten the nuts down, shifting from one nut to the other until it is not going to work itself loose while you're doing the other side. Repeat on the other side, and then torque both mounts down. Last, return to the lower shock mounts and tighten everything down. I had left the lower mounts and the sway bar mounts loosely threaded so I had maximum maneuverability while the front was assembled.

Start to end, this took me a few of hours, but only because I move slowly, it was 5*C (just over 40*F) when I did it and my dulling drill bits were a challenge. I probably could have moved faster if I really wanted to as well, but even in the cold, it was really nice to love on Hapy for a little while. Since Hapy is off the road for the winter, and his front seats are out (See Hapy Seating), I was unable to execute a test drive. Still, I expect the handling to be much stiffer, and my garage has gained about 3 cubic feet of floor-space. Win-win. Soon, we will hit the highway for a suspension test.

 

That's it for today. I intend to complete the seat install next, but finding time when the puppy isn't underfoot is the barrier. He needs constant oversight or he will eat something he's not supposed to. He's like a goat that way. He has no interest in being, and it has been too cold (4*C) to have him, tied up outside with me while I work for more than 20 minutes. And, he's too wiggly to just hang out inside the bus while I work on him. So, until I can solve for him, thanks for following along. I will disappear for a while again. If I get the chance to do something, I'll post on it-