|Parts||The sound system is made of the following parts:
2 Peavey Pro 12 Neo woofers
2 Peavey Triflex System Tweeters
2 Dayton audio 2.5 KHz 8 ohm crossovers
1 Pioneer GM-D9500F Class D car amplifier
2 Parts Express 50W 8 ohm L-pads
4 pairs binding posts
4 pairs banana plugs
25 feet of 18 ga. zip cord
24 0.187" 18-22ga. female quick-disconnect crimp terminals
2 32" long 16" diameter Sonotube concrete form tubes
2 2'x4'x3/4" MDF panels
1 Xtracycle Free Radical or equivalent
1 Xtracycle Flight Deck or equivalent
1 pair Xtracycle WideLoader H rails
1 pair Xtracycle V rails
4 Turnigy 11.1V 5000mAH LiPo battery packs (get 4 more spares)
1 tube Loctite PL Premium construction adhesive and caulking gun
12 10-24 tee nuts
12 10-24x1" machine screws
8 Strong-Tie A33 angle brackets
2 feet 1x2, preferably hardwood
|Tools||The following tools will be needed:
Power drill and twist drill bit set 1/16 to 1/4"
3/8" and 1/2" paddle drill bits or equivalent
Saber saw with medium (12-18TPI) blades
Compass or equivalent circle drawing gizmo
rotary rasp or curved wood rasp
The first thing to do is to obtain an XtraCycle or equivalent cargo bike.
The XtraLoud consists of two 32" long by 16" diameter tubes, each of which
is placed on one side of the Xtracycle using the WideLoader H rails as
bottom supports and the V rails as side supports. The deck is used as a
platform to hold the electronics.
The sound system uses standard PA system driver speakers. These are mounted securely into the MDF end panels, using machine screws and T-nuts. A pair of passive corssovers is used. These are mounted outside of the speaker enclosures, since one stereo channel faces forward and the other faces rearward, but the forward tweeter is mounted in the other cabinet from the forward woofer.
The speaker cabinets are made from a length of Sonotube or equivalent carboard concrete form tube. This may be obtained at a construction supply company. I used Border Products Corp. in Tucson. They take cash.
When buying the tube, get six feet total. You may ask them to cut it in half. You will cut it to length with a saber saw, and use the cutoff piece as a template to cut out the end plates from MDF.
You can get three end plates from one 2x4 foot piece of MDF, which is sold at the Home Depot. I bought two pieces and had some left over. Cutting MDF with a saber saw makes lots of fine dust, which is best not breathed. Use a dust mask, or sneeze a lot.
To get the right size of MDF end plates, use a piece of Sonotube as a template and trace the inside of the tube onto the MDF with a Sharpie. Cut the circle out with the saw cut right along the outer edge of the Sharpie mark. The goal is to get a tight fit, so that you have to tap the end plate into place with a hammer and block of wood.
File a chamfer on the inside edge of the MDF plate, all the way around, to make it easier to install.
Sand down the inside of the end of the Sonotube with coarse sandpaper. Wipe off the dust form the edge of the MDf and the inside of the Sonotube using a damp paper towel.
Set the Sonotube on the floor with a scrap piece of cardboard under the end. Apply Loctite PL glue to the inside of the Sonotube, spreading it with a finger to cover a ring about 3/4" in from the end of the tube.
When the PL is fully spread, it's time to install the MDF plate. Place it in the end of the tube, starting at one side, and guiding it into place. Don't let the side that;'s in the farthest go all the way into the tube, but leave the edge sticking out a little bit.
Eventually, you won't be able to put it in all the way. Use a block of wood and a hammer to tap it into position, ensuring that the block of wood overlaps the Sonotobe where you're tapping it. This will keep the plate from going in too deep.
When the plate is flush with the end of the Sonotube all the way around, repeat for the other end of the tube. Repeat the procedure for the other tube.
Let the glue dry.
Now you have two big drums. It's time to cut the speaker holes. You can start with the woofer end first, since it's easier and more forgiving. My saber saw has a circle guide, which works well for the 11 inch holes but not the smaller tweeter and port holes.
The woofer hole is centered in one end of each cabinet. Find the center with a ruler, drill a center hole, and use it for the circle guide. Make a compass out of a piece of string tied to a pencil and a nail, and draw an 11 inch diameter circle.
Drill an access hole just to the inside of the 11 inch circle, put the saw blade in it, and cut away.
Repeat on one end of the other tube.
The woofers mount with four 10-24 screws using T-nuts pressed into the rear of the end plates. Use the speaker as a template for marking the 1/4" holes. You will need to leave the woofers out to do the rest of the work on the cabinets.
The tweeter end needs two holes: one to fit the outside of the 4" drain pipe port, and one to fit the tweeter on the back of its flange. Place these holes next to each other, each centered in one half of the end panel.
Then drill a 3/8" hole for the L-pad to one side of the two big holes, and drill the four holes to mount the binding posts on the other side of the two big holes.
The bass ports are made from 4" ABS drain pipe. Each one is 2-1/2" long. They may be glued in place with PL adhesive.
Once all the parts fit nicely on this end panel, it is time to mount the tubes to the bike. The tubes are arranged with the tweeters up, with the left tweeter facing the rear of the bike but the right tweeter facing the front. you can set the tube on the wideloader rail to see how it fits. You will notice that the tube touches the rail a couple inches in from the end, but not exactly a couple inches, and the contact area is slanted. This makes it interesting.
The next task is to cut some wood blocks to press against the side and bottom rails, to keep the cabinets from sliding forward or backward. The blocks are placed inboard of the rails, rather than near the ends of the tubes. Each block also needs to be filed down with a rasp to match the curvature of the 16" tube. This is a hand fitting job, so take a couple hours to do it right.
It's a good idea to mount one block on the front side rail first, then mount its bottom rail neighbor, then proceed to the rear side rail, then the rear bottom rail. Repeat for the other tube.
To make a block, cut a 3" length of 1x2 and hold it against the tube at the angle that matches the rail. Make a couple marks to indicate where you need to file down the back of the block so that it will sit flush against the curved tube surface. File it down a while, checking the fit after a couple minutes, until it has a two-inch long contact area that is pretty close (1/32" or less) against the cardboard.
Then make a Sharpie mark on the tube using the rail as a guide to get the angle right. Drill two pilot holes (~1/16"+) in the block for 2d finishing nails to hold the block in place. Drill a pilot hole into the tube through one nail hole, but hold off on the other tube pilot hole until the block is positioned.
Drive one nail into the block, protruding out the rear a tiny bit. Apply PL glue to the back of the block and glue the block to the tube. Drive the one nail home into its pilot hole. Drill the other pilot hole through the tube, then drive the second nail home.
Repeat this procedure for the second block at that end, then for the two blocks at the other end of the tube, then do the same for all four blocks on the other tube.
Let the glue dry.
The tubes may now have their anchor brackets installed. One anchor bracket goes near each block. With the tube on the bike, hold a Strong-tie angle bracket against the end of the tube, with its angled end pressing firmly against the rail. Mark a center spot on the end panel using a hole in the bracket as a guide. Drill this hole out to 1/4" and install a T-nut in the back of the hole. Press the T-nut into position with a pair of Channellock pliers. Repeat for all eight brackets.
The amplifier, crossovers and battery box are all mounted on a 30" length of 1x10 wood (poplar) that replaces the Free Radical deck, or you can bolt it to the deck. I used a Techdeck at first, since it's made for bolting stuff to. But after I had used it a while, I removed the Techdeck and mounted its clamps directly to my board. The crossovers may be mounted side by side. I put the output terminals on the two boards next to each other.
The batteries are placed in a box. I built a box sides from 3" wide strips of oak that I had on hand. I cut a Lexan cover to let people see what's in the box. It's held to the oak with tiny #4 sheet metal screws.
You may also choose to use one 17AH lead-acid battery, in which case it doesn't need a box, only a couple straps and blocks to keep it from sliding around in case of bumps.
Now it's time to begin wiring the speakers. You will do best to solder the wires to the binding posts and L-pads. The L-pad has wiring directions. It connects to one pair of binding posts - I used the top pair for the horn and the bottom pair for the woofer, since that makes sense to me music-wise.
Each cabinet needs some absorber material. I bought a bag of it and split it in half, placing half in the horn end of each cabinet. This is best done after doing all the horn-end wiring but before installing the woofer. Glue the fill material in place. I used plenty of Scotch 77 spray adhesive. Use more glue than you think you need.
The woofer wires go straight to the lower pair of binding posts. I used .187" quick-disconnect terminals for all the speakers and for the crossover terminals. Feel free to solder these wires on for greater reliability but more effort removing the speakers for repairs. Make the wires long enough to be able to remove the woofer, set it aside and poke around in there.
The crossover wiring is a bit strange, since you have to connect the woofer of one box and the tweeter of the other box to one crossover board, and the other woofer and tweeter to the other board. This is why the crossovers are mounted outside the speaker cabinets, unlike any other stereo speaker system you've seen. I used orange and black banana plugs for the horns and red and black plugs for the woofers to identify them easily.
The Pioneer amplifier is used in 2-channel stereo mode, with each crossover connected to one speaker pair. The speaker wire pairs are on non-adjacent terminals in this mode, so pay close attention to the wiring diagram in the manual. Also pay attention to + and - to get the phasing correct, otherwise the sound will have weak spots in its frequency response. Don't forget to flip the mode switch to 2 channel stereo mode. Use the A left and right inputs.
The power wiring is a bit odd, since the power switch is an external device instead of a car stereo. Connect a toggle switch between the + battery terminal and the remote terminal. You may now use the remote terminal as a source of switched power to run all sorts of stuff such as a cigarette lighter socket to feed power to your MP3 player. I also added a voltmeter and a bright pilot LED to the remote terminal.
I used a dual USB socket cigarette lighter adapter (available at Target etc.) to make power for charging the iPod and to run 5V into my bike headlight. I powered the headlight with a USB cable with the B end chopped off and the red and black wires soldered to the + and - battery terminals in the headlight. This trick should work for either three or four cell LED headlights.
There you have it. Enjoy the loud music.