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Sealed Stereo Integrity HT-18D2 [build thread]

post #1 of 72
Thread Starter 
I'll be putting wood to blade this evening. Seems like the right time to start a thread.

The cabinet will be made with pre-veneered plywood leftover from another non-audio project. It is 18mm thick and while not perfect, it has been relatively void free after ripping into it a bit. I'm going with a single layer all around, including the baffle. Driver will be surface mounted, with a grill constructed in the future.

The net internal volume lands at 4.24 cubes, give or take the approximation factor of the 0.2 ft used for the driver's displacement. I will use 1.25" dowels as shown below for bracing. 8 dowels front to back, lined up with driver's mounting holes.

I will be using a Bash 500 that I already own. For my current sub I had modified some resistor values for a high pass / 3 dB boost centered at 18.7hz, 1.3 Q. The graphs compare this filter (in red) with the same amp, absent the filter (blue). Most likely I will be adding a little more power down the road and won't need to take this filter into account.









Larger versions of pictures here.
Bunch of driver pics here.
Edited by baniels - 12/14/12 at 6:49am
post #2 of 72
Bout g'damned time! biggrin.gif

Rendered cab looks pretty slick.
post #3 of 72
Holy tons of bracing Batman! Looks good tho.
post #4 of 72
I like a lot. I needed a few replacement drivers for my Def Tech pf1800's and I am going to give these a try. I want them to work and for the money I will be more than satisfied. I think you have a nice design there.

Good luck,

Robert
post #5 of 72
Thread Starter 
Cutting has been rescheduled to TODAY.

Question - I'm expecting that I will be adding a second one of these. Any thoughts on a suitable amp for a pair of these? A bridged NU3000 would be more than enough for one, but driving two, the rated RMS of 550w seems a little light. IIR, the ep4000 was tested at 660w or so, stereo 4ohm - also a little weak. Has anyone put the NU6000 to the test? Rated power at 4 ohm stereo is 2,200 watts. If that is true, it's probably more than I need - but even if it does half of that, It should be sufficient. Thoughts?

Next topic. Here is a sample piece of the plywood with 4 coats of poly (which is what I'm using for another project). Not sure I want to look at this every day. Any suggestions? Duratex? Anyone have good luck staining oak to make it less... boring?




As I wait to cut the wood, I've been toying with the idea of burying some threaded inserts in the dowels that line up with the mounting holes. 1/4-20 thread bolts will fit the existing mounting holes. I know that drywall screws would suffice, but I expect to get the Dayton DATS soon and have plan to experiment with different amounts of stuffing. I like the idea of not worrying about stripping anything out, and this should solidly couple the driver all the way to the rear, for whatever that is worth.


post #6 of 72
Stain the oak black ? Or red...
post #7 of 72
a darker stain will really bring out the marbling of the oak.
post #8 of 72
RE the oak. First I must say with the current trend to tissue thin veneer on most hardwood veneered ply you may have issues getting the poly off to stain it without cutting through the veneer. Assuming you can get the poly off (honestly unless you filled the grain first, which it looks like you did not you may be stuck painting) you have a lot of options. The first thing to consider when dealing with oak is whether to fill the grain or not, pretty much to a piece fine furniture almost always has the grain filled unless one is looking for a more rustic look (visual texture). For me I would usually fill the grain then use a "warm" oil finish one that darkens (warms) the wood but not stain it. I am not a fan of film finishes (like poly) since they leave wood lifeless or in the case of high build finishes plasticy looking. In the end if this were in my shop I would run the panels through either my wide belt or drum sanders taking a "thou" off at a time to try to save the veneer, then start over. Chances are you don't have either machine and it is unlikely you will be able to sand off the poly without burning through the veneer in at least a couple of places. If you want it to look like wood then I would mix some tint (ie Transtint) in with the poly and spray (or wipe if you don't have a gun) the cab so it looks stained. Failing that paint would be the next best solution, make sure to rough up the poly surface and use a paint that adheres to other film finishes well. General rule of thumb, poly over raw wood usually looks "dead". If one really wants to use poly it is best to dye the wood with aniline dyes to bring out the figure so that even with the poly over it is has much more of the look of a nice oil finish.


Edit: oops I missed it was just a sample! In that case consider aniline dye to bring out the grain (I would fill the grain first). Use alcohol instead of water for the dye since water will raise the grain big time on oak. I would use a oil based finish UNLESS you plan on the cabs getting wet (cups etc). Try the finishing forum on the Saw Mill Creek woodworking forum they are the AVS of the woodworking world, most of the other general woodworking forums are a joke.
Edited by PsychoM3 - 12/12/12 at 3:10pm
post #9 of 72
Quote:
Originally Posted by baniels View Post

Here is a sample piece of the plywood with 4 coats of poly (which is what I'm using for another project). Not sure I want to look at this every day. Any suggestions? Duratex? Anyone have good luck staining oak to make it less... boring?
Is that water base? Oil base usually gives a nice golden color. I fill oak with dark wipe on filler, like walnut, scrape the excess off with a credit card or plastic scraper before it sets, then sand until only the pores remain filled. That makes the grain really pop. I never stain oak, IMO stain is what you use to make bad wood look better but good wood look worse.
post #10 of 72
Quote:
Originally Posted by Bill Fitzmaurice View Post

IMO stain is what you use to make bad wood look better but good wood look worse.

Absolutely! I cut a lot of veneer from exotics for my different projects and stain would be the last thing I would ever use on them, aniline dyes however can be the best thing since sliced bread to get great figure to "pop". The Wood Whisperer did a good video which is very similar to the technique I have used for years to get grain to shine, especially in blonde woods where figure doesn't shine like it did when you first hit the board with a handplane and mineral spirits to gauge the figure. http://www.youtube.com/watch?v=yx8mp3Ag36s
post #11 of 72


That is probably the same oak after stain. I think it looks pretty darn good smile.gif
post #12 of 72
Thread Starter 
Quote:
Originally Posted by PsychoM3 View Post

Edit: oops I missed it was just a sample! In that case consider aniline dye to bring out the grain (I would fill the grain first). Use alcohol instead of water for the dye since water will raise the grain big time on oak. I would use a oil based finish UNLESS you plan on the cabs getting wet (cups etc). Try the finishing forum on the Saw Mill Creek woodworking forum they are the AVS of the woodworking world, most of the other general woodworking forums are a joke.

No problem. Lots of good information in your post regardless.

Quote:
Originally Posted by Bill Fitzmaurice View Post

Is that water base? Oil base usually gives a nice golden color. I fill oak with dark wipe on filler, like walnut, scrape the excess off with a credit card or plastic scraper before it sets, then sand until only the pores remain filled. That makes the grain really pop. I never stain oak, IMO stain is what you use to make bad wood look better but good wood look worse.

Yes it is water-based. I was pushed in that direction for the other use of the wood (dining table top/billiard conversion for in-laws), because the smell of the water-based stuff tends to be less offensive, and the speed at which I need to complete it means I can't let it fully cure out before delivery. They are fine with that sample -- I just don't want it for my sub.

Can you recommend a good brand of filler (or what to avoid)? I'd may give that a try.

As for the cutting, I was most of the way done, but in my rush I made a critical material management error. Will finish up tomorrow.

Any thoughts on my amp question?
post #13 of 72
the 6000 is just two 3000's in one enclosure.
post #14 of 72
Thread Starter 
Double rabbets are 66.67% complete. With luck I'll start gluing tonight.

post #15 of 72
Thread Starter 
Dry fit looks good.



Edited to add:

Dowel placements marked, speakon hole drilled, sides gluing to the bottom. Calling it a night.


Edited by baniels - 12/14/12 at 11:44pm
post #16 of 72
When you guys say that you are going to fill the grain, do you mean fill with like wood putty, or what? Can you explain the purpose, and proper technique for the?
post #17 of 72
Thread Starter 
Top/bottom/sides assembled. Most of the dowels in place, glue curing.




post #18 of 72
Holy Dowels Bat Man. smile.gif
post #19 of 72
Thread Starter 
That's only half of them smile.gif
post #20 of 72
Quote:
Originally Posted by baniels View Post

That's only half of them smile.gif

i was going to ask why so many but i see your using a single baffle

edit: wouldnt it be easier to use a double baffle and less dowels?
post #21 of 72
Thread Starter 
Quote:
Originally Posted by brian6751 View Post


edit: wouldnt it be easier to use a double baffle and less dowels?

Yes, I'd have to say so. I was trying to do this all with wood I had on hand. I believe the dowels will be adequate, and I've been wanting to test this idea of coupling the driver all the way to the opposing wall of the cabinet. If I weren't wanting to try that out, I probably would have sought an alternate form of bracing the rear.

Currently gluing on the rear.




This is my first time using PL Premium. I gave myself an 1/8th to trim from all overhangs. I was happy to see the excess PL will trim off nicely when I flush everything up.

post #22 of 72
Thread Starter 








Next step is to sink these into the final 8 dowels (and hopefully do it straight).
post #23 of 72
8 more dowels coming??? Did you have to double the airspace of the cab to accomodate the extensive doweling? biggrin.gif

I love it -- that box should be solid!
post #24 of 72
Thread Starter 
Believe it or not the dowels displace just under 1/3rd cubic feet.
Quote:
Originally Posted by Aaron Smith View Post

8 more dowels coming??? Did you have to double the airspace of the cab to accomodate the extensive doweling? biggrin.gif

I love it -- that box should be solid!
post #25 of 72
are you just using the expanding capability of the pl premium to seat the dowels?
post #26 of 72
Thread Starter 
More or less. I flexed the panels apart slightly with a just-oversized dowel when I put them in place. When I removed that the panels provided some clamping pressure of their own, and I added a touch of external clamping while it cured. I drilled holes into the dowel ends and filled with glue to mate with the gobs on the panels. There may be more elegance in a different order of operations.
Quote:
Originally Posted by beastaudio View Post

are you just using the expanding capability of the pl premium to seat the dowels?
post #27 of 72
Subscribed. :cool.gif
post #28 of 72
Quote:
Originally Posted by baniels View Post

Believe it or not the dowels displace just under 1/3rd cubic feet.

I do believe it -- was just remarking on the complexity of the "Dowel Labyrinth" (probably because I would have stopped at 1/2 that amount). smile.gif As noted, definitely a stout build!
post #29 of 72
Thread Starter 
Some more progress.

When I first approached driver alignment for mounting holes, there was a little resistance. The corner of where the mounting flange attaches to the basket has a slight radius. Black shows the rub marks.


Tiny roundover fixed this.


Just before lining it up.



It dawned on me that I could use the doweling jig I had recently purchased. Worked quite nicely.


The first insert went in straight.


Recessed slightly so it doesn't get in the way when I glue to baffle.


This is why my inserts are not centered in the dowels. Centering them would cause the dowel to encroach on the cut out. It also allows me to swivel them slightly if any of these dowels are too close or touching any of the cabinet dowels. I drew it all perfectly, but my drawings and reality have slightly different tolerances. By first look, I won't need to shave anything down to get them all to fit.


These are the feet I'm using. Penn Elcom 9106. These things are a very beefy 1x2.5" rubber. I think they'd support my house. They attach to a flanged knock-in threaded insert accepting a 1/4-20 bolt.


All of the rods and inserts are set.


The true hero of this task was the robust t-handle hex wrench. Trying to thread in those inserts with a common L-shaped hex would have been a real PITA.


Sneak peak.
post #30 of 72
Excellent craftsmanship.
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AVS › AVS Forum › Audio › DIY Speakers and Subs › Sealed Stereo Integrity HT-18D2 [build thread]