Please Help me build a box for my dad's trike!!

[evanp]

Hey guys. This is my first post. I'm trying to hook my dad up. He bought a new trike about 6 months ago. It's a 2023 Harley-Davidson Roadglide 3 Trike.

Being a trike it has a small "trunk". I'm trying to put 3 8"s in it. At first I was going to build a box, but 3/4" MDF eats so much of the little volume I have, it's not a good idea.

My plan is just to make the trunk itself part of the box, and lay a perfectly flush panel of plexiglass over the 3 down firing 8" subs.

I am just having lots of issues. Please I need help.

I would like the plexiglass to go where the cardboard is on the second picture.

Click to read more...

 

[evanp]

The trunk has so many angles arcs going on. I'm totally lost.

I spent 4 hours trying to make what I thought would be a template out of MDF and I botched the whole thing.

I also built a sealed box, but it's so small, if I could just put a plexiglass panel to seal the subs, I could basically double my volume and go from the bare minimum Sq ft for the smallest sealed box to a decent sized ported box.

 

[Buck 5,000+ posts]

One piece of advice from a dude who's done tons of like "shouldn't fit" or funky box designs, don't try to fit more than you can in the airspace allowed. I'm not saying that's the case, just saying in general. You need to figure out your airspace total inside of whatever box you can make before you decide on sub types and numbers. You have to have the proper airspace for the woofers to work properly.

I would probably stick with sealed myself in this type of situation, because it'll be easiest to work with, and mainly because it controls the woofer much better than a ported box will in this type of environment, IMO. I would just fire the subs upwards with the sealed section in the bottom, where the bass fires up like it would in a car trunk. Not sure what is meant by down firing these subs, downfiring into what? The bottom of the little trunk? More explanation there might help.

I'm sure there's a lot I don't know here about your specific situation or might be missing info, but that's my general thoughts.

 

[Buck 5,000+ posts]

And cool build! Sure is a challenge!

 

[audiobaun 5,000+ posts]

Ya.. Im not understanding the Down fire in that situation either, and looks like craming some subs in a Tuna can to be in all honesty. I prob would have done a single 10 sealed myself on some power. Dont need much, and I prob would have considered a 2 ohm load for drw consumption or even @4 ohms to keep it safe. Thats me though

 

[evanp]

When I said down firing I mean the subs are pointed downwards, I'm going to make a 1" spacer between the sub and the trunk floor, that way when tbe subwoofer is hitting and moving back and forth, it won't hit the trunk floor.

Instead of cutting an actual hole in the trunk floor for the subs, I'm going to use a drill and drill rows of holes until the trunk floor almost makes a mesh pattern. This will protect any rocks or Debris from hitting the subs as they will be otherwise exposed to the undercarriage.

Think what the grill looks like on a GMC Denali. I'm going t2o put a pattern like that in a hole shape for each of the 3 subs.

If I were to use an mdf speaker box (like the one I made), I wouldn't have enough volume for 3 subs. If I used the trunk itself as a box, I'd have copious room for 3 subs.

This brings me back to my original dilemma, how can I make a template of the exact angles of the trunk so I can make a plexiglass panel to seal off the subs? If viewing the trunk from the top (birds eye view) there's no straight lines, there's a mild curve on the parts that almost appear straight. If viewing the trunk from the side, the back of the trunk slants at an angle. It's pretty complicated and I need to make a very snug surface.

Once again, this MDF template is close but no cigar and it took me around 5 hours to make it!

 

[Buck 5,000+ posts]

nvm gotcha now

 

[Buck 5,000+ posts]

I think you're gonna have to get good with fiberglass or something, or find someone with a 3d laser scanner that can 3d print or mold you some kind of part.