Bought the Civic Hatch lease out, so rebooting the install thread

[geolemon]

So a mock-up with the spacer for the functional top of the sub box. There's clearance for that as well.

I'll need about another 1/2" for a trim + carpet layer, and I'm good for that too, so I'm leaning towards this baffle.

Now I need to transfer this to a fresh piece - base it on a 14" circle, and I'll make a baffle adapter for each sub so the cosmetic is consistent.

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[geolemon]

Haven't had nearly any time this week to work on this, with a 7/1 critical corporate project deadline looming - I logged nearly 80 hours, many of my team logged more - and I can't wait to get back to this. Murphy's Law, right?

To avoid Murphy's Law on this project, you know how it goes - plan, measure, reconsider, measure again, test fit, test fit, test fit.

This is looking in from the portion facing the taillight, and you can see - although the W7 fit with breathing room, the GTi fins touch the back wall before the sub flange sets down on it's adapter.

Fortunately, I anticipate this is an easy fix. I have several inches behind the box - I can jigsaw a simple cutout, then cover that hole with a 3/4" panel on the outside. I'll not only gain 3/4" additional clearance, but also additional rigidity (not that this tiny panel needs it) and a tiny bit more volume even, if I oversize that cutout. Might as well, if I have the inch I think I do.
Will test fit that next.

I'm also concerned with how tight this needs to be in this area by the taillight. I'll stretch fleece for the shape here - but I have to be concerned both with "getting too close to the JL magnet" or "creating an interference fit with the taillight pod".

So of course - I'll stretch and test fit the sub, then test fit the box. Test fit, test fit... test fit.

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[BigAl205]

Not to insult your intelligence, but you are taking the displacement of the sub into consideration during your calculations, correct?

PS, loving the progress

[geolemon]

Also -

I loaned out my router table and router and probably should have picked them back up... So easy cutting perfect first-try circles that way.

But instead, in breaks between meetings, I channeled my inner 17 year old - broke out the trusty jigsaw and sniper stare and steady-handed my compass-drawn circles.
Old school.

So if course that means I'll need to do some cleanup work at the belt sander to perfect those circles - and even still a few of these will at least get 3/8" roundovers - so I do need to my router table back ASAP.

But at least I made forward progress-
Here's how it will work:



The baffle is nearly fully round.

Each woofer has it's own 1/2" adapter ring with a proper sized cutout, to mate it properly.

Outside that is a 3/4" (but I think I need to make it 1" ) thick trim ring. That will be 3/8" radiused on each edge except where the grille rests - serving double duty to space that grille out far enough for W7 excursion.

Then inside the box - the ring on the floor will be cut in two halves so it can be removed and serviced if it ever needs it.
This is a ring which will have threaded inserts at all the "plus" marks...
Twelve for the W7, eight for the GTi.
I think I'm using this size threaded insert that's on the floor, for this (can use 10/32 skateboard hardware).

It'll be held in place initially by one screw per half, just enough to hold it in place on the back side. Then once the hardware is threaded in and tightened - it will really sandwich the baffle between the mounting ring and the sub flange.

Plenty of shaping and bodywork to come... Even before stretching fleece.

I'll want to do my buildup inside, after the fleece cures - that's going to be fun.
I'm thinking to facilitate that - and even to facilitate the fleece stretch - I may even need to make a flange to bolt this piece to the lower segment - rather than make them inherently conjoined into one solid enclosure.

[geolemon]

Not to insult your intelligence, but you are taking the displacement of the sub into consideration during your calculations, correct?

PS, loving the progress

There are none - I've got what I've got, it's one reason for going sealed. And for picking subs that are monsters, sealed. And for having a pretty big sub amp.

But bear in mind this upper part is just to hold the sub. I'll be happy if I have a half cube up there.

The lower half of the spare tire will is deceptively big -
It's about 4" x 16" x 24" above the tire well, and the bottom part is curved and smaller but figure about another 4" deep x let's call it effectively 10" x effectively 22", just for estimates sake.

So that works out to about 1.5 cu.ft.
Plus there will be some little airspace up top.

I'm not traditionally a fan of using the minimum recommended airspace for sealed boxes - but I'll have more than that (1.0 cu.ft for 12W7, 1.4 cu.ft for GTi 12).
Qtc .707 would be nice - but I think I'll have less space than that (higher Qtc).

It's also an advantage of running a DSP for this install, because I can tweak the curve down there if needed.

[geolemon]

So this will amuse any ex-or-current pro installers out there...
Avoidable engineering.

For customer cars, you never want to over-engineer... It risks over-promising and doubling your labor time, and more waste, possibility of backing yourself into a corner...
So I'd be more conservative. Probably not totally recess the sub. Probably have that baffle protruding 1" more than the "absolute minimum" that I'm shooting for here.

As a result, I'm removing bracing that I had... Moving it elsewhere.
I'm carving magnet clearances with my multi tool into the wood...
I'm having to cut that rear opening to gain 3/4" depth for the GTi...
I'm having to engineer a flap to hold the fleece so it doesn't cause an interference with my taillight pod...
I'm having to notch a baffle brace and re-enforce it in jenky ways because my original to-the-floor would have been an interference...
...and still need additional engineering to not just stiffen it that brace, but will conjoin it with a magnet support brace to allow me at least a *chance* of being able to install and remove these heavy subs once it's all installed.
I have a big gap I will need to fill...

If I was one of my old fabricators, I would have fired them.

Just kidding (unless it was a recurring thing of course). But I would have relentlessly teased them for sure.

Good news is my work project should let up this month, so I'll have time to get more action on this. Less prep, more install!

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[geolemon]

Added that rear cutout for clearance - used 1/2" MDF because it's such a narrow span and the overlap itself acts as a stiffening brace, and I do have my car's pressure vent back there. Tons of glue, I want this sealed.


And to clarify - the point of my prior post is really twofold...

1) A pro installer can't afford to take this kind of time pursuing micro-adjustments to get clearances down to an eighth-inch. They work smart and fast, out of necessity. And do you see that gap where I cut on the table saw? Will be some avoidable filling/fixing work, if it was on-the-clock.

2) I could have avoided all this jenkiness that adds additional work now and later...
Cutting an assembled part on the table saw...
Adding a flap and plastic brace to hold fleece rather than simplify the design and loosen my tolerances.

I might be exaggerating when I said "one inch" - but for sure, if I had this structure simply TWO inches protruding into the hatch - I'd totally have avoided ALL these cuts and after-the-fact tweaks.

But it's two inches that I WANT.
And it makes it a fun challenge.
But damn it makes this piece a cosmetic mess inside. It'll be one hell of a contrast with the outside.


So anyway -
I also made a few additional curved cuts, and sanded some curves, anticipating how I want the fleece to stretch into my final shape.

And this means it's time to shape my rings and get my router and freestyle table back. All I need to do is my 3/8" roundovers and I'm ready to fiberglass.

I'm actually ready to 'glass first, but I do want those shapes to line up well BEFORE I do.

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[geolemon]

And -
This one especially. All these would be no-go pics in a pro shop log book.

If this wasn't my own car - this wouldn't fly for anyone else's car. I'd be restarting - and again - from minute one, the plan would be to not get into this, by simply building tolerances into the install.

Totally unprofessional - if it weren't my car and "me" being the one who has to have confidence that I've kept structural integrity at 100% - because NO customer ever should see visible "reasons to worry". Ever.

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[geolemon]

So at any rate - it's on me to make sure any last minute adjustments don't compromise my finished install integrity and quality. That's what ultimately matters. That's what I have my focus on.

If I were a competition guy also - then for sure these would serve as prototypes - I'd continue with the install up to the fleece stretch and first resin, get the hinges, actuator, power, and possibly RCA and speaker wires routed - but then pull it out and rebuild, using these as templates.

But it's just cosmetics that won't be seen... And to be fair wouldn't be seen even in a competition context - but for competition you don't take chances on judging or judges. It's not just listening.



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[geolemon]

On a related note - I changed my strategy on getting air to the fans. I decided to carve a big Panama Canal into what was a 100% solid MDF angled support structure at the back of the hatch to pull air in from behind the rear seat side panel voids, rather than router two [possibly too] thin vertical channels (one per fan) down to the lower chamber.

Better breathing, and better cosmetics.
The outlet fans won't be an issue - they will blow into an open space.

Sadly while I was doing this, I totally burned out my trusty multi-tool, not that I was abusing it or anything by letting it thermal-stop then putting it in the freezer to cool it down... maybe 4x or 5x times...
It was a couple hours of carving, even with a recip-saw assist.

Unfortunately my multi-tool is also my detail sander (via different tool head on the motor). My concern here is really avoiding dust (including sawdust) being pulled into the amp rack - so rather than try to clean out and paint that new canal, I decided to paint the entire canal with wood glue. Ultimately I think this will be superior to sanding and painting it.

And with all that tunneling modification going on - I ended up needing the wood glue to restore a couple cracks that I caused by forcing that vibrating tool of destruction in there... As you can see by where the cracks formed, it again shows that proper glue joints really ARE stronger than the original MDF - so I'm not worried about these new glue joints at all.

Final picture shows the amp rack lining up to the new air canal inlets. Fortunately my orbital sander is still fine, so I'm going to be able to sand and prep those top edges, and install the piano hinge here, now.