2016 Porsche Macan S - stealth SQ build

[Ge0]

Okey doke. I have more drawings to share.

Here is the JL Audio 10TW3-D4 crammed into place



There are more than a few clearance issues here. Now, what if I shave off 1/4" off the OD of the mounting ring?



Now I can push the sub out from hard interference's. However, the mounting rings are pretty darn thin. Hmmm... Try to make it work or not?

Just for shits and giggles I drew up what the Dayton LS10-44 would look like. Damn, I bet I could fit two of these in my sub floor.




Options and more options...

Ge0

[geolemon]

I didn't include the Dayton LS10 but did model up the eights since I was curious and I did include the Sundown SD4 as a reference point to tie back to your other graph:

Blue line - two Dayton ultimax eights, sealed, 2 cu.ft.
Green line - two Dayton ultimax eights with two Dayton 10" PRs with 125g added mass each, 2 cu.ft.
Red line - the Sundown SD4 10, sealed, 2 cu.ft.

EDIT:
that's these-
Two of these: https://www.parts-express.com/dayton...iator--295-494 (there's an aluminum cone version for $2 more) that would have to be mounted on the outer side of the enclosure, obviously...
Two of these: https://www.parts-express.com/dayton...-coil--295-508

It is a lot of cones to fit across that space, but utilizes it and extends the response, if that fits.

I also kinda personally love the idea that casual onlookers and audiophiles alike would look at that and think you either were mixing sub sizes, or if they understand PR's might think the flat-coned subs were really the PRs, and the cone-and-dustcap PR's were actually the subs.

[geolemon]

Okey doke. I have more drawings to share.

Here is the JL Audio 10TW3-D4 crammed into place...


There are more than a few clearance issues here. Now, what if I shave off 1/4" off the OD of the mounting ring?

Now I can push the sub out from hard interference's. However, the mounting rings are pretty darn thin. Hmmm... Try to make it work or not?

This is what I was suggesting... "2a" before.

If you literally just came in 1/4" on all sides, yeah there would be four spots where the MDF would be pretty thin, but that's not inherently a problem. It's a small spot. It's not like an entire wall of the enclosure. I'm certain it wouldn't flex, much less blow out - and consider fiberglass enclosures are frequently entirely 1/8" thick walls. If you were really nervous about those spots, you could even mix up some plain 'ol epoxy resin, get some wire screen or even thin fiberglass strips - band-aid sized - spread out some epoxy over the thin area (on the inside of the box), embed your screen or fabric, another layer of epoxy - and bam. Re-enforced.

Realistically, especially if this isn't sealed, you'll blow your gasket seal before you had enough pressure to blow through even 1/8" MDF - and I'm sure you'll have more than that even in the thinnest spots, right?

Also - if you were wanting to avoid that entirely, my "2b" suggestion was to just carve a flat spot between two of those mounting nubs, space for the tire to go into. Yeah, the sub would end up rotated a bit, but if you turned it toward the trunk opening - I think that would look like you actually gave it more thought, not less. "Yeah, that's where a person would be standing to look into the trunk". And maybe you could carve a little into other spots to really tuck it into the corner, but those two spots you'd be making the mounting tab locations thinner.
Options.

Just for shits and giggles I drew up what the Dayton LS10-44 would look like. Damn, I bet I could fit two of these in my sub floor.

Is the outer diameter REALLY less than the smaller "diameter" dimension of the JL's?
I'd think the sort of "square" nature of the JL frames with the tabs would actually offer you more fit options ("2b" mentality) - even if they really engineered that terribly for reverse mounting.

[Ge0]

If there was a big cost savings I would check out the Dayton as well, sure - and I'd also compare excursion capability for linearity and output considerations, among other specs - but otherwise like you show, it's pretty clear the Sundown is likely the better choice.

My thought on "why suggest with the two Ultimax 8's NOW" is because I didn't realize before that they would be THAT squeezed, from a diameter perspective - especially if you are recessing.
Seems like a good, if not great option to maintain (or exceed) output with a smaller, easier diameter.
Curious why didn't you include them in your model? Aren't you shooting for a 2 ohm load? I'd think 500 to a pair would be nearly perfect, and in 2 cu.ft - you'd likely even want it smaller for that 0.7Qtc, which would give you an easier installation overall:
Attachment 10936
And from that you are right, technically you could even fit three, but that spare probably wouldn't leave you with room for a middle on, or you'd be squeezed in the same way as the 10 on the end.

There probably IS more risk with [these] two eights [in particular], to supply enough displacement to break your seal, as opposed to a single ten - but I don't know the excursion or Qes (or BL) on all the above. Note if you modeled up one eight on 500w, two would just be a mental shift of the line 3dB higher... or you could simulate by fudging the power number to push it 3dB higher.

Glad you highlighted the JL in the comparison - you can tell from the .28 Qts that it would likely underperform in a sealed box. That's really surprising to me - people who shop for shallow subs are usually squeezed for space, they really need all the "small box sub" alignment you can give them... and it's easier to design a sub with LESS motor strength than it is with MORE - I'd think if JL simply made the coil longer on this sub here, they'd easily lower Qes, Qts, and increase Xmax all in one fell swoop (provided that didn't make thevVC former strike the back plate - maybe a bump would be needed)

Anyway - just wondering how that option compares. But of what you modeled, especially if the Xmax is similar and the Qts/Fs is more "sealed box friendly", I'd buy the Sundown and be done with it.

I can't use the Dayton Ultimax 8" in this design iteration due to stack height. The magnet would hit the floor and at the very least choke off the rear vent on the magnet structure. In the future I plan to raise the floor up 2" to make more room underneath. But at that point I would have a huge selection of subs to chose from including some 12" models.

I think you were looking at QTS for the SBA sub. The JL 10TW3-D4 has a QTS of .62

Ge0

[Ge0]

Is the outer diameter REALLY less than the smaller "diameter" dimension of the JL's?
I'd think the sort of "square" nature of the JL frames with the tabs would actually offer you more fit options ("2b" mentality) - even if they really engineered that terribly for reverse mounting.

I think it is just a scaling issues with the drawings converted to photos. The Daytons over all O.D. is 0.2" larger than the JL's bolt circle diameter. However, the JL's overall O.D. is 0.5" larger than the Dayton.


About the JL's mounting ring. Does anyone have a good idea on how to trim down the outer diameter of a ring that has already been created? It gets kind of tough once the center has been cut out. I'll try shaving it down another 1/4" to 3/8" over what it is now to give me more space to play with.

Ge0

[geolemon]

If you have even a cheap router table and can work slowly, you can do it, but practice with a scrap ring first (you'll need to anyway, to mark and set your depth), so you see what will happen:

1) you'll need to set the fence further forward than you would if you were trimming a straight board down, because the ring will be curving inwards, into the gap in the fence, to contact the bit.
2) the ring will be only touching the potentially sharp corners of the gap in your fence, which can make for friction - sharp edges pushing into the MDF, etc, making it tough to rotate. So don't push hard, and just do it slowly.
3) when you are finishing up the circle, be very careful - you may even want to not quite complete the circle using the router table, clean it up by hand. The fence/depth will have been set based on having all the material you started with on the ring, and as you return around to that starting point, you'll have part of the ring that's already been trimmed, which could make your wood dive into the router and cut more deeply than you like. You'll see - so just be careful, that last bit will be fairly manual.

Besides that last little nub that you'll want to be careful with, you'll get a perfect reduction. Very easy.

EDIT:
The lower-tech option you'll really need to be careful:
Make a roughly sub-diameter circle of scrap wood to temporarily secure to the JL ring with double-sided tape (so it's mounted like the sub, and flush with the top of the decorative part of the ring), and use those mounting tabs and a ruler to locate the center of the hole. You might want to make that circle as large as possible, to make for a stabilizing surface for the jigsaw base plate to stay flat, to ensure a straight 90 degree cut.
Draw a circle using a compass, at the location you want.
Follow the line slowly and accurately using the jigsaw.

I'd then recommend that you use an upright belt sander with the table set to 90 degrees to smooth out any imperfections, so you might want to cut slightly larger than your pencil line, and then sand into it until it's just gone. Technically that would also get you a perfect circle, but there's a lot more requirement to rely on your eyeballs and your own care and patience.

EDIT 2:
You might not even need the precision - I wasn't thinking, this cut edge will be hidden inside the box.

[DaveG]

I think it is just a scaling issues with the drawings converted to photos. The Daytons over all O.D. is 0.2" larger than the JL's bolt circle diameter. However, the JL's overall O.D. is 0.5" larger than the Dayton.


About the JL's mounting ring. Does anyone have a good idea on how to trim down the outer diameter of a ring that has already been created? It gets kind of tough once the center has been cut out. I'll try shaving it down another 1/4" to 3/8" over what it is now to give me more space to play with.

Ge0

How about a rabbet bit with an oversized bearing? They sell them with a range of changeable diameter bearings. Just trim half of it with the rabbet bit and then flip the ring over and finish with a flush cut bit. That's how I would do it anyway.

[Ge0]

How about a rabbet bit with an oversized bearing? They sell them with a range of changeable diameter bearings. Just trim half of it with the rabbet bit and then flip the ring over and finish with a flush cut bit. That's how I would do it anyway.

You know what sir? That will absolutely work! I was thinking how could I do this with a rabbet bit or flush cut bit. I drew blanks. It never occurred to me that I could do one then the other. You get a gold sticker for the day. Thanks!!!

Ge0

[Ge0]

nice work so far!

Thank you sir...

Ge0

[Ge0]

Going to switch gears here for a moment and look at something else. How about midranges?


Here it is





Overall mounting depth including connector protrusion:



Now extract the driver by removing two torx bolts:



The third mounting point may be an isssue:



The driver:




Some important measurements we will need:








More in about 5 minutes. I have to pee...

Geo