High end audio in the Sliing

Thanks to a thread Sparcky started a while back, I have decided to install a system this winter. I initially didn't want a system at all, for the main reason Sparcky pointed out, in that your legs are blocking the speakers. I am going to address this issue in a couple ways, using speaker placement, horn loaded compression drivers, and lots of power. My entire system is going to be four speakers and a four channel amp. I am using my phone as my headunit, with a separate volume knob. I am also doing the big three power/ground upgrade on the Sling also, with 1/0 gauge wire.

I am not planning on installing subs, for a couple reasons. One is that my mid-bass speakers should play pretty low, and can handle lots of power. The second is, I agree with the concept that a sub needs to be in an environment that helps compress the soundwaves. In a normal vehicle, the sub frequencies are in a sense being compressed because the soundwaves are rebounding inside the vehicle, increasing the pressure. More pressure is more volume. The only way to overcome this is in an open environment to increase the power to the subs, with enough power that the single soundwave carries enough pressure in the open environment.

The horn loaded compression drivers (tweeters) are the main reason I decided to build this system. They are placed under the dash, in front of the driver and passenger. The shape of the horn directs most of the energy across the vehicle, instead of straight ahead. In the first pic, you will see the yellow tape I put on the horn. This tape shows the direction that they project the most energy. In the second pic, I have the horn at the distance it will be from the driver/passenger, and you get a better sense of the projection of the drivers side horn towards the passengers ears. The third pic shows where it will be installed. They are tucked up under the dash, and although it's hard to judge in a pic, they are not in the way.

The mid-bass are going to be installed in UAS pods. The UAS pods are clearly the largest pods available, which is why I went with them. I contacted UAS and asked the volume of the pods, but got no answer, so I ordered them anyway. I needed to know the cubic feet of the pods, before I could decide on the mid-bass speakers. I used packing peanuts, and a .125 cubic foot carboard box to measure out the peanuts. I was able to fit .375 cubic feet of peanuts into the UAS pods. I bought high end Morel mid-bass speakers, which I have been wanting to use for years in other projects, but never bought because of the cost. Cost isn't a priority this time around. The pods already have a hole cut into them for a speaker, but I am moving the speaker as far forward as possible, so they won't be blocked by my leg. I am going to 3D print small pods to bolt onto the UAS pods, which will also cover the existing hole. The printed pods also place the speaker on a slight angle, pointed towards the driver/passenger a little bit. I am printing grilles also, to snap onto the 3D printed pods. In the following pic, the green circle shows where the speaker will be moved to. I have created all the programs for the 3D printed parts. Each piece is 15 to 16 hours print time, so it's gonna take a while.

The amplifier I chose is from Audiocontrol, 120 watts per channel and built in signal processor. I am using a Bluetooth receiver, so I can use my phone as the headunit. The volume knob plugs directly into the amp itself. I plan on putting the volume knob in place of one of the empty rocker switch openings underneath the push start button. I took the knob out of it's housing, reverse engineered the dimensions of it, and I think it will work without cutting any part of the dash. Here is a pic of the knob next to a rocker switch. I will be 3D printing a plate to mount the knob.

Don't let anyone tell you 3D printing is easy.

Quote from DJohnson

Hey I have done that one before. You got to love when that happens on the 35th hour of a 36 hour print job. Normally I am sleeping when it starts.

Yep. It was supposed to be an 18 hour print. I checked it right before I went to bed, and some of the surfaces seemed odd. I woke up about 15 hours into the print. It seems like the nozzle was coming unscrewed, and may have been the problem.

I am currently printing with PETG, but I think I am going to switch to PLA+. Since I am printing solid pieces, that are going to be bolted to a flat surface, I am not so worried about UV light or temperatures affecting the parts afterwards.

I printed a dust cover out of TPU (flexible filament) for the side of my amp with all the connections. It also covers the connections I am not using.

I never got to say this before, but it's tighter than I thought it was going to be

Made some progress. I was able to print my speaker pods out of 'PLA Professional'. I made some mistakes, like the grille was designed to snap onto the pod around the entire periphery. I need to do a lot of benchwork, to remove some material so the grille only has a couple tabs for the attachment.

You can get a sense of the added angle I added to the pods, to tilt the speakers towards the driver/passenger. The snap on grilles are going to be covered with grille fabric, after I insert an aluminum grille in the opening to protect the speaker.

I started to work on my speaker pods. I cut out the fiberglass, and used threaded clips to be able attach my relocating pods. The snap on grilles are going to have an aluminum mesh insert over the speaker, and be covered in grille fabric. I may use grille fabric that is normally used on guitar cabinets, because it is more of a plastic than a fabric.

I was thinking about adding some foam onto the grille, before applying the fabric. The area where the speaker cutout was originally, is right where my knee rests. The foam will actually fill in a gap, where the fabric was just going to be pulled taught, with no support behind it. I figured the foam would also prevent my knee from stretching the fabric.

I put my driver's side pod in place, and took some pic's. You can see how much of the speaker is exposed from both seating positions. I figure, if I can see it, I can hear it.

Mid-bass grilles are done. I hot glued the aluminum grille material in place, and hit it with red spray paint. If it's possible to see thru the fabric at all, I wanted a subtle accent to match the red stitching of my seats, and steering wheel.

I finished sound deadening and wiring my mid-bass pods. I am using waterproof connectors for the input leads. Instead of using plastic loom, I used OEM style loom tape (JK Tapes) on all the wiring. The speaker leads are wrapped with an interior grade tape which is soft, to keep down any rattling. The input leads are wrapped with an abrasion resistant exterior grade tape.

I do have some things to complain about. I weighed making my own fiberglass pods versus buying pods. It was more economical to just buy the UAS pods, at $600, and modify them. One issue is, one of the pre-drilled mounting holes goes thru the actual interior of the pods. Whether it was a sealed box or a ported box, that hole is a vent that screws up the performance. I made a wall out of a couple layers of Dynamat to seal it off. My second issue is the thickness of the fiberglass. The flat front panel may as well be a drum skin. I spent about an extra $90 in dampening materials. I was going to use some damping materials regardless, but I had to go further than necessary.

I made some progress. I was able to fit my volume knob in place without cutting any of the dash. I tried to 3D print the mount, but I ended up machining it from the textured plastic that I like to use. I machined a pocket for the knob itself to fit into, to make the assembly a little more flush.

I found a place to mount the large fuse for my Big 3 upgrade, for the wire that goes from the alternator to the battery. There was an existing hole in the frame, where I installed an M4x.7 threaded insert. I 3D printed a mount that cradles the frame, so the fuse holder could be more secure.

Here is a comparison pic of the Big 3 wiring ground wire (1/0 gauge) versus the factory. Just like the power wire, I am just piggybacking the Big 3 onto the factory wires. I replaced the ground from the block to the chassis, and added a ground from the alternator body to the chassis.

I ran all the wires. marked them, and pulled them back out. Then I made two harnesses, one for the power and one for the RCA, speaker, and data wires. I wrapped them in factory style tape, and was able to run power on the driver's side of the tranny hump, and RCA's on the passenger side. Here is where the harness ends at the amp location;

I replaced the 12 volt outlet in the glove compartment with a waterproof USB jack, which is the data connection for my amplifier;

I fabricated a mounting plate for my amp out of 1/2" thick plastic plate. Since I am mounting the amplifier upside down, I machined some pockets into the plate, to try and help vent the heat.

Amplifier is installed and wired up. If I ever need to work on it in the future, I just need to remove the one body panel below the rear deck. It was a tight fit, and the RCA wires barely clear the gas tank vent hose. I realized that I can raise the mounting plate about another 1/2" to make more clearance, but I would need to buy longer bolts.

I got my pods and speakers installed. The pods would not fit with my plush floor mats in place, so I had to cut the mats. The things you can't see are, the magnets for the horns clear the frame by only about 5/8", and clear the firewall on the passenger side by about 3/4". I will be making grilles for the horns, and covering them in the same grille cloth.

Horn grilles are finished and installed.

I was on the fence about adding a line driver. I started to double guess the output of my phone's signal power, taking into account that the bluetooth receiver's RCA output is only 1.5 volts. I ended up adding the line driver, which theoretically should increase the RCA output to 9.5 volts nominal. So my system consists of a bluetooth receiver, a line driver, and an amp.

I have a Rockford Fosgate test disc on my phone, and I used both a 400hz and 1khz test tone to set the line driver input to match the bluetooth receiver's output. I have built a few bluetooth boomboxes, and I normally have my phone's bluetooth volume set at 3/4. I tried 3/4 volume with this line driver, and I guess the signal was too clean to clip the signal. I maxed out my phone volume, which finally started to clip the signal, so that is how I ended up setting the line driver. I plan on leaving my phone at 3/4 volume, so I should always have a clean signal.

My install is on now hold until my new battery arrives. It is currently on backorder. I ordered it in November when it was on sale, and I hope it gets here before my riding season starts. It is an Antigravity ATX30-HD, which has two positive and negative terminals. I want it for both the upgrade that it is, and that it will simplify my wiring. I can leave the stock wiring as is, and run my Big 3 and amp wires to the other terminals.