SEOS-12 / DNA-360 / JBL 2226(J) build - Page 2

I made a template on some thin plywood: traced the waveguide outline, then made an outline 3/32" bigger than that all around, cut it out using a jigsaw and filed / sanded to clean it up; then clamped the template to the baffle, and routed within the template using a 1/4" straight bit and 7/16" bushing. Final step was cutting out the middle with a jigsaw.

Thanks Nick, I hadn't considered that, I'll mull it over - I do know that whatever roundover I do on the slot will be fairly small, like 3/8" or so maybe, since its so close to the bottom and sides of the cabinet.

I made the trip to Ganahl - yay open on Sundays - and picked up two 5x5 sheets of BB plywood, and had them cut to fit in my SUV; brought it home and marked and cut the pieces (sides, backs, tops, and bottoms; and managed to get one cabinet dry fit together (no glue yet, since I need to cut and fit the piece that forms the last side of the slot port, which is probably easier without the baffle attached.



(drill shown for scale - these are pretty beefy bookshelves )

Thanks Nick - I'll be adding some bracing, haven't thought much about the details yet - maybe just simple midpoint stick/dowel braces front-to-back, side-to-side?

Thanks tux - already thinking ahead to how I'll get one of these up on top of a ladder in the back yard for measurements.

Thanks Craig - the main consideration for me was extension (see WinISD graph earlier in the thread, comparing -3 dB point for sealed vs. ported). I decided that I'd like to be able to run them a bit lower, to do a crossover to sub at 60 Hz - not sure that I'll run them like that, as I'm currently crossing my mains at 100 Hz, but I didn't want the design to prevent it, especially since they have 15s in them. Ported also means bigger boxes, and a few more variables to juggle (box size, tuning, port velocity / resonance, excursion below tuning). I'm a relative noob too, others more experienced in speaker design might chime in with other factors that I've left out.

I guess I also wanted a little more challenge / learning experience, and since its DIY, to build something a little different.

Thanks BP - I can't wait to see them put together too! Also can't wait to get off work so I can make some more progress.

Up to now, I had no reason for AT screen backlighting - but it sounds more appealing now.

Wonder what each of these suckers is going to weigh - closest guess wins a pack of Fits gum.

Confused now about WinISD port "End Correction" when it comes to slot ports. For circular ports, you can pick flush or flared ends, and it adjusts the port length to compensate. For rectangular ports, it inserts a numeric value, I'm not sure what I'm supposed to do with it - subtract from port length? add? nothing?

For 16 x 1.75 slot port, it says 11.61 length, .732 end correction. So should the port length be 11.61 or 11.61 - .732 or ?

Googled for some answers, and got a lot of contradictory interpretations.

Thanks mtg90 - when I said flush I meant flanged - and realized after I posted that it doesn't support flared.

I guess I'll just go for 11.64 port length (10.14 extension past the 1.5" deep baffle) and see what I get. Seems pretty consistent with what I get for a circular port of equivalent cross area and one flanged end.

Got the other two washing machines er cabinets dry fit together before it got past power tool curfew. Grr. Need to remember to stop for a couple tubes of PL on the way home tomorrow too, thought I still had some, but only about 1/3 of a tube, and didn't want to run out in the middle of assembling a box.

Here are the three washing machines - boxes glued up with PL, except the baffles, which are still just screwed on until I have the mounting holes drilled.



Woofer and waveguide held in by gravity:



A closeup of the slot (shelf?) port.



Also shown are the markings for the mounting screws - boy they're close to the edge, front mounting drivers is kind of annoying. I ordered these, thinking they'd work better than T-nuts/hurricane nuts, since they don't need as much space:

http://www.amazon.com/gp/product/B002WC8TU2/ref=oh_details_o01_s02_i00



...but still not much room to operate. The holes may (will) hang over the edge, and I'll have to bury them in epoxy. Or angle the screws, not sure which is worse. No space on the back to be able to do a roundover either.

Thanks I definitely will let you know and take advantage of your kind offer to assist / spoon feed me.

Yeah I may do just that, I guess I'll wait for the inserts to show up in the mail and take a close look at the size, and if it looks like a no go, save them for later projects, and use screws for these.

Thanks

Thanks Scott - they're not quad 15s, but they'll have to do! (hint hint build thread hint hint)

Thanks bg - thinking I'll just go with screws though, just too close to the cutout.

Made a little more progress yesterday and this morning: 1/4" roundover on back of woofer and waveguide cutouts (since I'm doing screws for the woofers, figured why not); drilled pilot holes for the woofers, and holes for the threaded inserts on the waveguides, and screwed them in; glued/screwed on the baffles; used a trim router bit on the sides and back; and belt sander to trim the baffles (too deep for a trim bit to work, at least the ones I have); 1/4" roundover on slot ports; 3/8" roundover around all exterior edges; bondo'ed and sanded screw holes.

You can see I went a little nuts with the 50 grit belt sanding in a couple places, so will need to fill / sand a bit more before primer.



Will work on bracing next - thinking just a window brace horizontally between woofer and waveguide, or just "stick" bracing front to back and side to side.

I wonder if I should also brace the center of the slot port - any thoughts?

Edit: scratch the "window" brace - won't fit through the woofer hole. Sticks it is.

Bracing: