Announcement

Collapse
No announcement yet.

SevenSixTwo - InDIYana 2018 Coax Design

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • KEtheredge87
    replied
    After a day off due to contracting some kinda cold bug, I got back at it tonight. I custom fit the other two cabinets' coax chamber walls and got them glued up. I also cut my dowel supports and realized I didn't buy enough dowel for 3 cabinets AND the temporary tools. Oh well... I'll go pick up another bit of dowel stock tomorrow. Getting closer and closer to doing some real measurements!

    Click image for larger version

Name:	20180205_204812.jpg
Views:	56
Size:	599.0 KB
ID:	1364100 Click image for larger version

Name:	20180205_204816.jpg
Views:	60
Size:	907.6 KB
ID:	1364098 Click image for larger version

Name:	20180205_204824.jpg
Views:	60
Size:	569.9 KB
ID:	1364099

    Leave a comment:


  • KEtheredge87
    replied
    Post #2 today - Photos of the slot port glue-ups and dowel marking tools

    Click image for larger version

Name:	20180203_153840.jpg
Views:	60
Size:	629.0 KB
ID:	1363759 Click image for larger version

Name:	20180203_153829.jpg
Views:	58
Size:	568.4 KB
ID:	1363758 Click image for larger version

Name:	20180203_141812.jpg
Views:	57
Size:	969.1 KB
ID:	1363757 Click image for larger version

Name:	20180203_141846.jpg
Views:	61
Size:	910.9 KB
ID:	1363756 Click image for larger version

Name:	20180203_141852.jpg
Views:	59
Size:	555.8 KB
ID:	1363755

    Leave a comment:


  • KEtheredge87
    replied
    Whoo boy, lots of progress today! Got the ports glued in to the other two cabinets, so those are drying overnight. Figuring out how to push the ports down near the inside wall was tough. I kept re-inventing my approach with the spreader clamp to make it work, and it eventually got done. I also completed my mini-project threaded insert replacement for the one janky insert on the test cabinet. That plug cutter and JB Weld KwikWood epoxy did a great job of filling the hole after removing the insert and drilling the hole to size. After flush cutting and a little sanding, you'd hardly even notice there was a plug in place!

    I also made some dowel rod "markers" to use when I start assembling the other side wall. I intend to epoxy some 1" dowels across the cabinet, so I needed a way to mark the location on the other cabinet piece. Using some blind nails in some sample dowels should do the trick. All I'll need to do is line up the oversized outside wall piece then push it down onto the nail heads to mark my locations. Then I can use the forstner bit to make a shallow recess with diameter that's 1/8" oversize. This will allow me to pour some epoxy around the dowel to lock it into place inside the cabinet once it's all glued up.

    I took a boat load of pictures today, but I'll try to choose wisely. Here's 5 pictures with most of the threaded insert replacement process. I'll post some more pictures below this entry for the rest of today's work.

    Click image for larger version

Name:	20180203_113106.jpg
Views:	64
Size:	443.7 KB
ID:	1363750 Click image for larger version

Name:	20180203_120944.jpg
Views:	62
Size:	460.1 KB
ID:	1363752 Click image for larger version

Name:	20180203_122713.jpg
Views:	63
Size:	519.3 KB
ID:	1363749 Click image for larger version

Name:	20180203_142326.jpg
Views:	60
Size:	597.8 KB
ID:	1363751 Click image for larger version

Name:	20180203_143759.jpg
Views:	61
Size:	502.1 KB
ID:	1363748

    Leave a comment:


  • KEtheredge87
    replied
    Happy Friday night everyone! I'm spending time catching up to myself constructing the two "real deal" cabinets up to the same point as my test cabinet. I did have a good laugh along the way though. My wife told me that all my clamps holding the walls to the front/rear/top/bottom remind her of Dr. Frankenstein's monster... so I guess I'm officially an evil genius!

    This evil genius plans to glue the slot ports into the cabinets this weekend, as well as install some 1" poplar rod braces and hopefully glue up the other wall of each cabinet. Solid chance I'll have to go buy more clamps at harbor freight to do all these glue-ups at one time. Somehow my collection of 16 twenty four inch long bar clamps just isn't enough to keep this project rolling without spending a day between glue-ups. Darn that whole "waiting on glue to dry" thing.

    One last mini-project plan... my test cabinet ended up with one threaded insert being off the mark. I bought some tapered plug cutters and JB wood weld epoxy from Lowes, and my plan is to remove the threaded insert, use MDF plugs with wood weld epoxy to fill the first hole, cut/sand that smooth, and drill a new hole in the proper location. This is what I get for trying to be smart and pre-drilling holes for inserts based on a bolt circle and pencil lines instead of just using a vix bit to drill a centered pilot hole!

    Anyway, here's a few more picture of Frankenstein's monsters

    Click image for larger version

Name:	20180202_181411.jpg
Views:	64
Size:	679.0 KB
ID:	1363593 Click image for larger version

Name:	20180202_183935.jpg
Views:	59
Size:	632.0 KB
ID:	1363592 Click image for larger version

Name:	20180202_183834.jpg
Views:	60
Size:	926.8 KB
ID:	1363589 Click image for larger version

Name:	20180202_184002.jpg
Views:	59
Size:	580.9 KB
ID:	1363590 Click image for larger version

Name:	20180202_183953.jpg
Views:	59
Size:	606.5 KB
ID:	1363591

    Leave a comment:


  • 4thtry
    replied
    Originally posted by KEtheredge87 View Post
    . . . . See Bill, 4thtry , I'm still leading the way with my mistakes . Since I have threaded inserts in those areas, I used a sanding drum on my dremel to knock back a little bit of the MDF on those spots. I didn't go too deep, so I shouldn't compromise the threaded insert while giving a little bit of clearance to the tabs and solder beads where the tinsel connects.


    [ATTACH=CONFIG]n1363064[/ATTACH] [ATTACH=CONFIG]n1363067[/ATTACH] [ATTACH=CONFIG]n1363063[/ATTACH] [ATTACH=CONFIG]n1363066[/ATTACH] [ATTACH=CONFIG]n1363065[/ATTACH]
    Nice recovery! Your mistake has now become an innovative mounting technique!

    Leave a comment:


  • KEtheredge87
    replied
    Bit more gluing done tonight, as well as some custom dremel work. One thing I noticed last night with the test cabinet was that the Esoteric driver has it's solder tabs connected to a spoke on the cast frame. Just so happens that spoke is also in line with one of the mounting holes on the flange. Which of course, means that the solder tabs are nearly interfering with the front baffle and are not sitting in one of the relief chamfers like I was planning. See Bill, 4thtry , I'm still leading the way with my mistakes . Since I have threaded inserts in those areas, I used a sanding drum on my dremel to knock back a little bit of the MDF on those spots. I didn't go too deep, so I shouldn't compromise the threaded insert while giving a little bit of clearance to the tabs and solder beads where the tinsel connects.

    After the dremel work, It was time to make a glue mess. I assembled the two other slot ports and put together cabinet 2 of 3's front / back / top / bottom. Good thing I found a few more clamps in my not-so-organized garage near the scrap MDF section! I want to get these cabinets as close to final cuts as possible as soon as I can so the joint lines that will get veneered or painted have some time to expand. Not only that... but that means I'll be getting into the XO phase of the project! I have so much to learn and experiment with there, starting with simply taking good measurements of a coaxial driver in my cabinet!

    Thanks again for following along!

    Click image for larger version

Name:	20180130_203021.jpg
Views:	58
Size:	818.9 KB
ID:	1363064 Click image for larger version

Name:	20180130_203903.jpg
Views:	52
Size:	527.3 KB
ID:	1363067 Click image for larger version

Name:	20180130_204353.jpg
Views:	49
Size:	813.4 KB
ID:	1363063 Click image for larger version

Name:	20180130_221426.jpg
Views:	54
Size:	449.2 KB
ID:	1363066 Click image for larger version

Name:	20180130_221450.jpg
Views:	52
Size:	526.0 KB
ID:	1363065

    Leave a comment:


  • KEtheredge87
    replied
    Originally posted by 4thtry View Post
    I usually load my box alignment and port dimensions into WinISD and then test this using the velocity tab. If the port air speed is 50mph or less with about 40 to 50 watts applied, I figure that I am OK

    Originally posted by Kevin K. View Post
    Keith, it would be a shame to veneer the entire cabinet and then try the roundover on the port only to find out you don't like the end result. Seems you have more than enough veneer, cut a slot in a piece of scrap, cover it in veneer and then try the roundover to see if it's turns out the way you want it to.

    I didn't go back and look at the BB plots, were you marginal on the velocity and that's what has you concerned?
    Thanks Bill and Kevin,

    I hadn't posted any BB6 plots yet since I was too busy fiddling around with wood glue and DATS. My only real (and likely unfounded) concern is this project is the first slot port I've ever designed. My readings on this forum have me thinking these are somehow more difficult and/or prone to port noise if done incorrectly. The BB6 plots attached below suggest that I am fine with my current arrangement. Xmax for this driver would be breached after ~50 watts, and the RMS power handling is 100W, so I'm in fine shape there Even bumping things up to xmax + 10% only lands me at 60 watts. The port velocity for my 12.75" long x 4" wide x 3/4" high port never exceeds 21 m/s under a 50 watt load. More than anything... I just sweat the details to a fault!

    On the veneer then round-over idea, I will absolutely test this on a scrap piece first. Honestly, The bassbox model now only has one flush end included (in my case... the interior end of the port) and it's darn near spot on with the impedance measurement I took yesterday. If the experiment proves to be a bad idea, I'll post it for learning here, and go with a flush end facing out. No reason to ruin the project!

    Thanks for the prod to give myself an (in)sanity check! Back to wood glue!

    Click image for larger version

Name:	SevenSixTwo BassBox Model Esoteric Woofer.jpg
Views:	74
Size:	229.1 KB
ID:	1363060
    Last edited by KEtheredge87; 01-30-2018, 11:48 PM.

    Leave a comment:


  • Kevin K.
    replied
    Originally posted by KEtheredge87 View Post
    Evening everyone!

    Does anyone have any thoughts, concerns, or ideas on testing that port before getting any more committed? I can still re-hash things a bit if need be. I haven't glued together the other ports, or cut any slots in the other front baffles. Now would be the time

    Thanks for following along
    Keith, it would be a shame to veneer the entire cabinet and then try the roundover on the port only to find out you don't like the end result. Seems you have more than enough veneer, cut a slot in a piece of scrap, cover it in veneer and then try the roundover to see if it's turns out the way you want it to.

    I didn't go back and look at the BB plots, were you marginal on the velocity and that's what has you concerned?

    Leave a comment:


  • 4thtry
    replied
    I usually load my box alignment and port dimensions into WinISD and then test this using the velocity tab. If the port air speed is 50mph or less with about 40 to 50 watts applied, I figure that I am OK

    Leave a comment:


  • KEtheredge87
    replied
    Evening everyone!

    A simple update for this evening. I took my test cabinet slot port back to the table saw and trimmed ~1/8" off to adjust the Fb I was measuring. That ended up raising my Fb to 30.95 Hz, which is plenty close enough for me (and probably waaaay close enough for the not-so-anal among us) to the BB6 models. Final slot length is 11 3/8" for the slot section inside the cabinet, overall length of ~12 3/4" when you add the 1 1/4" thick front baffle.

    Click image for larger version

Name:	Port Tuning 2 - 30.95 Hz.PNG
Views:	77
Size:	76.2 KB
ID:	1362843

    What I would really like to test before I go much farther is whether I will get any port noise out of this setup. I have no XO filters assembled for this speaker yet, but I can probably slap an inductor coil in series with the woofer just to give me a low pass. Just need to run some bass through it to see if I get any nasty chuffing noises from the port. The port itself has a smallish internal flare with the 1/4" roundover I applied, and I have intended on routing a similar roundover on the front of the cabinet after veneering. BUT... that is pending an experiment with paper backed veneer and roundover bits. If adding a roundover to an edge like that results in a ratty looking seam, or a bunch of tearout, I'd be required to keep the cabinet as a flush port on the front.

    Does anyone have any thoughts, concerns, or ideas on testing that port before getting any more committed? I can still re-hash things a bit if need be. I haven't glued together the other ports, or cut any slots in the other front baffles. Now would be the time

    Thanks for following along

    Leave a comment:


  • KEtheredge87
    replied
    Originally posted by jhollander View Post
    Keith how are you adding the veneer to the box? I've been spending some time at Joe Woodworker so I'm thinking about building a bag and vacuum bagging my veneer on the box.
    Hi John, The short answer is by using an iron-on method with paper backed veneer and the heat lock glue that Joe sells. However... I can't seem to make anything simple, so get a load of this complicated mess I'm planning.

    For my heat lock veneer shenanigans....

    Part 1 - Wrap the front, top, rear, and bottom with one long sheet of veneer that's 1/8" to 3/16" wider than necessary. I plan to cut 1/8" deep x 1/4" wide slots around the perimeter on each edge of the veneer with a slotting cutter and an obscenely large diameter router bit bearing. To avoid chip out on the veneer, I intend to climb cut this so the slot cutter blades are always slicing down from the top of the veneer instead of pushing fibers away from the cabinet like I would get with a conventional / push cut.

    Part 2 - For the side panels, I will again place a 1/8" - 3/16" oversized square of material on the side panel. I will make an MDF template with side walls that fits snugly against the cabinet to make sure I'm in a consistent location when the tool gets used on each side of the cabinet. From there, I'll use a template bushing and a down cut spiral bit to carve a 1/4"x 1/8" groove into the side panels to trim away excess veneer and give me the design aesthetic I'm after.

    Part 3 - Painting. Once I have all the veneer in place, I'm going to meticulously mask it off with delicate surface frog tape (the yellow stuff) and try to get some black automotive spray paint on the exposed MDF edges.

    Part 4 - Veneer finishing. I plan to do some fancy dye work like the curly maple finishes video from Woodworkers Source on Youtube. I love the way that Mark puts his videos together, and I've never had a finish turn out badly following his recommended methods!

    Assuming I don't screw all of this up... I'll end up with something like the Fusion360 renderings I made earlier in this project. Fingers (and eyes and toes) crossed!

    Finally, on the topic of vacuum bagging. I have only used paper backed veneer with heat lock thus far in my speaker building career, but I have done several vacuum bagged carbon fiber composite panels in grad school, so I'm generally familiar with the processes that Joe lines out on his website. The technique really isn't hard to do if you've got the right equipment. Lots of fancy breather cloth, platens, valves, vacuum bag tapes, and then the bagging material itself. Perhaps the process doesn't really require all the trimmings that funded research can afford you

    Leave a comment:


  • jhollander
    replied
    Keith how are you adding the veneer to the box? I've been spending some time at Joe Woodworker so I'm thinking about building a bag and vacuum bagging my veneer on the box.
    Last edited by jhollander; 01-29-2018, 10:45 PM. Reason: spelling

    Leave a comment:


  • KEtheredge87
    replied
    Post number two for today: Veneer and Port Tuning!

    Outside of the test cabinet construction, I received my 4x8 sheet of quartersawn curly maple veneer from Veneersupplies.com (Thanks Joe!). The wood is beautiful on its own, and I can't wait to get a bit further along in the project to start some test panels for finishing

    Since I have an actual slot port to play with now, I figured It was time to take an initial swipe at the cabinet port tuning. One wall of the cabinet is yet to be glued on and flush trimmed, so this helped the process a lot. I used 1" thick quote "project foam" from Walmart to line the walls of the ported enclosure, since I modeled my enclosure that way in Bass Box. I mounted the Dayton Esoteric woofer with the machine screws, as planned. Only one of my threaded inserts was a bit off-kilter, but I'm not 100% sure how that happened. Regardless, I'll have to remove that insert, glue some kind of dowel pin plug into that hole, and try again with a fresh drilled hole. This is why you can see 5 screws and one blob of 3M poster tack on the woofer.

    BassBox had my cabinet predicted at an Fb of 31.18 Hz based on a 4" x 3/4" x ~11" slot port, flares on both ends, and 0.65 ft^3 of internal volume. DATS V2 measured my Fb at 28.9 Hz (granted this was with only one flared entrance (inside). Not too shabby for a first crack. I took two measurements in DATS. One has only four clamps holding the cabinet together, and the other has six. I'm not pretending this is perfect... in fact there's probably a good few places for air to leak out of this setup. Unfortunately there's no good way to tune this kind of slot port arrangement without gluing both the port and the wall to the cabinet.

    In order to fine tune these Fb results, I will take a little length off the internal slot port tunnel. I plugged the current 28.9 Hz Fb value into BassBox to see the impact, and it predicted 0.5 dB less output between ~50 and 100 Hz. Possibly not noticeable, but that would also have me approaching xmax sooner, and I'd rather not go there. Once the final length has been established, I'll cut the other two port tunnels to that length and move forward. Getting closer and closer to crossover time!

    Click image for larger version

Name:	20180127_174601.jpg
Views:	76
Size:	571.8 KB
ID:	1362698 Click image for larger version

Name:	20180127_174515.jpg
Views:	62
Size:	827.3 KB
ID:	1362697 Click image for larger version

Name:	20180128_180826.jpg
Views:	63
Size:	671.4 KB
ID:	1362699 Click image for larger version

Name:	20180128_190011.jpg
Views:	75
Size:	962.6 KB
ID:	1362700 Click image for larger version

Name:	Port Tuning 1 - 28.9 Hz.PNG
Views:	77
Size:	72.6 KB
ID:	1362701

    Leave a comment:


  • KEtheredge87
    replied
    Hello Everyone, Update time!

    Lots of detail work progress this weekend. First, I trimmed up the slot port tunnel that I made on Friday and gave it some 1/4" rounds to help flare the inside opening as well as make the whole thing a bit friendlier to the touch when I'm digging around in there later. The delicate part was making the slot cut through the front baffle to match up with the slot tunnel on the inside. I had to make some layout lines inside the cabinet to get the port centered on the inside face of the front baffle. From there, I drilled some holes through the front and jigsawed away as much material as I could to let a flush trim bit reach down into the tunnel. I tried a 1/4" flush trim bit to start, but it didn't have enough cutting length to reach all the way through. Lucky for me I have a gigantor 1/2" flush trim bit from my Jedi Mind Trick subwoofer project that WAS long enough. I switched back to the 1/4" bit afterwards to clean up the corners. This was important because there's still a slight lip on the inside corners of the port tunnel where the front baffle transition happens. leaving it with the 1/2" bit left a larger lip. Using the 1/4" bit to get the 1/8" radius in the corners should help blend that in considerably.

    Here's a few pictures from the woodworking adventures this weekend. Next post will have veneer info and initial port tuning!

    Click image for larger version

Name:	20180127_130940.jpg
Views:	84
Size:	556.4 KB
ID:	1362693 Click image for larger version

Name:	20180127_133356.jpg
Views:	65
Size:	868.9 KB
ID:	1362692 Click image for larger version

Name:	20180127_134436.jpg
Views:	61
Size:	841.4 KB
ID:	1362691 Click image for larger version

Name:	20180127_145014.jpg
Views:	65
Size:	939.9 KB
ID:	1362689 Click image for larger version

Name:	20180127_145042.jpg
Views:	77
Size:	891.0 KB
ID:	1362690

    Leave a comment:


  • Wolf
    replied
    My vertical jig is very similar to what you made, and rides the fence on the table saw. The problem I had most in use was alignment of the setup. Shift it a smidge and it was no longer perpendicular. I had to hold it and clamp to it just so to get exactly as I wanted.

    Glad you got through it with the result you wanted, and that you did it safely.

    Later,
    Wolf

    Leave a comment:

Working...
X