Hexagon Pioneer B20FU20 Enclosure

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John L said:


There are probably some ways to get around this. First, the diffuser will have to be large, and curved enough to allow the high frequencies to be dispersed around the room at a lower level, more where the person is sitting.

And second a more efficient compression horn will tend to work better than just a high efficiency tweeter. If you look at all three models Duevel use, they are all high compression horns. HC horns are almost always far more efficient than other tweeters, and should be far better at taking up the slack.

That's just my guess, of course.


Incidentially, that must be the reason why you have that PE tweet facing front and center in your new project. ;)

As I understand it, the human ear is most sensitive as a locator in the 2-6khz range and I think this may be why many true omni's are said to be poor imagers. They disperse all the frequencies in this range, resulting in a lot of reflections and arrival times that are too quick to the listener, unless they are placed the perfect location, usually far from any walls. I believe the hybrid approach offers an excellent in room power response, yet avoides more of the reflection problems that can smear the imaging in that critical region. You will notice that the Beolab 5 is only omni in the front 180º, rather than 360º. YMMV! :)

I believe the reason that Duevel uses large compression drivers is that they are high sensitivity and can cross much lower without stress than most dome tweeters. They are also designed to use in horns, whereas domes are not. A compression would probably be good to try. On the negative side, I think most are pretty high in distortion. There are trade-offs for every decision is a speaker design, however.
 
One of the things I discovered, while reading the reviews of the Jupiter, is that the reviewers stated that the Jupiter worked best if it was approximately 36" out from the wall or the corner. That made a huge difference. Also, the direction it was turned mattered as well, because the manner in which the sound, coming from the porting made a subtle but vital difference.

This picture give you some idea as to how the Jupiter treats the movement of sound Behind the driver. I had never really paid any attention until I started paying closer attention to some of the pictures.

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Before this, I had always looked at the bottom of the Jupiter and Bella Luna as just a black area, with no earthly idea as to how it worked down there. But after this picture, I began to notice subtle differences in the cabinet bottoms on some photographs.

With pictures like this, of the bella luna, it is easy to overlook what is happening.

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It just looks like a flat surface there. But ocassionally there are shots that are more reveiling.

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There are others, but I have gone through so many pictures of these cabinets, literally hundreds, and cannot keep up with where I saw them all. The point that was brought up earlier about this project being more than just a 'box' issue, is correct.
 
dlneubec said:

I believe the reason that Duevel uses large compression drivers is that they are high sensitivity and can cross much lower without stress than most dome tweeters. They are also designed to use in horns, whereas domes are not. A compression would probably be good to try. On the negative side, I think most are pretty high in distortion. There are trade-offs for every decision is a speaker design, however.

I have done some rooting around in that regard, and there are some HC horns that appear to be quite good. But you have to look closely, And be prepared to fork over some nice investment with some. It is easy for some of these to go over $200 each, so picking and choosing is essential.

Here are a couple of pretty good choices. One is the B&C DE250-8 1" Polyimide Horn Driver. Here you can get some idea of it's specs.

Also, there is the B&C DE500-8 1" Neo Titanium Horn Driver. The data sheet is right here.

this Selenium D3305Ti-DPD 2" Titanium Horn Driver, also appears to be a nice one. Here is it's data sheet.

There are plenty of HC horns out there, but so many of them have good curves, IF you are willing to crossover much higher, or if you are willing to compromise. But there are also some very good ones too.

An example of what i am talking about is the Selenium D210Ti 1" Titanium Horn Driver 1-3/8". It's currently on sale at PE, and the price is right, but if you look at it's data sheet, you can see that it is much less than perfect.

But on this first project, I am going to go with the tweeter I mentioned at the first of the thread. If it does not pan out, I will have to go to other extremes.
 
Hi John,

One of my problems with most of the pro type drivers is the lack of independent testing by folks like Zaph, where you can get a direct comparison to more typical home Hi-Fi drivers It would be nice to have that information before you plunked down that kind of cash based on jut the manufacturers published specs.

I've read most of the internet reviews of the Duevel products as well. However, I never read an explanation of what is happening in the black angled areas. What is your take? Are they simply ports? I'm not sure how that clear version illustration applies to reality. BTW, I believe the low end drivers used in the Duevel Bella Luna and Jupiter are PHL drivers, which are pretty pricey.
 
I suspect we will need to get Dave back into this discussion. His contribution right here is worth checking out. I think his reference to a "pipe" effect may be a valid one.

Just looking at the Jupiter and it's venting, as it is, tells me that there is more than just porting involved here.

Unfortunately, I cannot copy this, because I have braces dadoed and glued in place which would make this impossible. It's within reason to hope that proper venting and stuffing of the tube will work too.

Also, maybe Scottmoose can give his input as well.
 
While I was glueing up other parts of the cabinet, I happened to think of the big difference between the Titebond II and the Better Bond Heat Lock glue. I learned the hard way, on this project, about what to look for with regards to what the glue looks like when it dries.

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As you can see, the Better Bond dries to a very dark colour, and unless you are using a dark veneer, or dark stain, it is not the best product for your veneering needs. The Titebond, on the other hand, dries to a much ligher shade, and will not be noticed, in the joints, as will the Better Bond.

For this reason, I recommend the Titebond II glue for ironing on veneer, except in the rarest of instances. And as a further plus, a gallon of Titebond II costs $18.99 at Lowes, while the Better Bond costs $34.95. Clearly a major consideration of about $15.
 
I have now gotten to the point in the project where I need to be thinking about the diffusion lense and the driver setup. Here is where I stand today.

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All the preliminary work is complete with the cabinets and the bases. When everything else is finished, I will come back and clean up any over-application of shellac in places, and reapply several more coats. Then I will repaint the bases two or three more coats.

I will also add that I have another class scheduled with the lathe instructor for all day Wednesday. Hopefully I will have the proceedure down pat enough to complete a pair of lenses. If not, I will go back for a third session.

Almost everything is tentively complete on the top cap of the cabinets. Here is what the caps looked like before routing out the hole for the driver.

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I had tried to get the fit as snug as possible, but later learned that this is unnecessary, and even not recommended. A seal running around the inside and under the cap will work just as well.

And here is what a cap looks like with the hole routed out and a reinforcement underneath the cap. In this picture you can clearly see my foul-up with the dado cuts, which I talked about earlier. I had filled in the cut with other plywood and applied enough glue to make it completely saturated in the stuff. It shouldn't be going anywhere, but it certainly looks terrible and I Know about my foul-up. I cannot guarantee that I will never do that again either.

Here is the cap turned upside down, with the inner cabinet exposed. I used the OSB because I had plenty of it setting around as scrap, and I needed something to help brace the bolts that would be holding down the driver. it should also add stiffness to the cap.

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All the cleats were cut at approximately the correct angle, and were glued and screwed to the lip of the rabbet cut-out of the cabinet. Once my speaker mounting kits arrive, I will drill a hole centered near the edge of each wall, that goes into each cleat, and use it for bolting down the cap to the top of the cabinet. Also, for versatility, it can be unbolted and removed for changing out the driver in the future, if desired.

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Here is the other cabinet that does not have the foul-up.

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In the cap finishing department I had tried to come up with the most practical and best looking way to finish the cap. Origionally, I thought that some form of black plastic "L" shaped edging would be nice for finishing off the top of the cabinet. By using an Exacto knife and cutting angles, plus scoring the inside of the plastic, I would bend the edging evenly around the cabinet top. Unfortunately that did not work, because the plastic kept breaking on me at the scored areas, so I finally had to give that up. My thoughts of having a nice even trim around the top of the cabinet were dashed there.

However, I finally came up on the idea of just acquiring some black Plastic Laminate, and using contact cement to glue it to the top, and having an overlap, which could then be trimmed off once the lid was placed on top. The P/L would fit perfectly along the top, and I could adjust it to match the edges by shifting the lid around a little bit before tightening the speaker mounting bolts securely.

This is where I am at the present. The weather is just too cold to be out there in the snow, on the back deck, painting on contact cement. I'll have to wait until it gets above the freezing point, and all this global warming melts away. :)
 
dlneubec said:
Hi John,

Have you or anyone else tried Titebond III for the iron on method? I'm curious to kow what difference it would make versus II.

No, but I have closely eye-balled it over at Lowes. And it is almost the same dark colour as the Better Bond glue. If I let it dry, it too would dry quite dark. I'll take a pass on as well.

I know what Titebond II looks like dry, and I also know that it works almost as well as the Better Bond, because there are more than enough testimonials about it on the internet. And it costs about 40% less than the Better Bond brand. And while Titebond II is not 100% waterproof, it is good enough for just about any application.
 
Hi John,

I've used TB III many times and it dries about the same color as it starts. It is not nearly as dark as that one you posted in the Arby's bottle. I think it might possibly be a better color for all but the lightest woods, like Birch, Maple, Aspen, etc., assuming it works as well with the iron on glue method. I used it to egde glue up a Maple baffle (with biscuits) and it is barely detectable. I can take a photo if anyone is interested.
 
dlneubec said:
Hi John,

I've used TB III many times and it dries about the same color as it starts. It is not nearly as dark as that one you posted in the Arby's bottle. I think it might possibly be a better color for all but the lightest woods, like Birch, Maple, Aspen, etc., assuming it works as well with the iron on glue method. I used it to egde glue up a Maple baffle (with biscuits) and it is barely detectable. I can take a photo if anyone is interested.

Yes, that would be very informative. :)
 
Disabled Account
Joined 2007
Hi John,
Thought about veneering the cap?
I'd be tempted to do it like this:
 

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MJL21193 said:
Hi John,
Thought about veneering the cap?
I'd be tempted to do it like this:

I had indeed. But there is only one little problem with that approach. If you will note, I had made a rabbet cut along the top of the cabinet pieces. this meant that the cap fits down inside the walls. If I veneered the top cap there would still be a 3/16 outer portion that would not be finished. By applying a P/L piece to the top and trimming it all around, the entire top would be finished, and removable. Only if I could come up with a thick enough piece of wood would that work, and the overhanging portion would still be more fragile than the P/L.

Also, the driver is black, as will the diffusion lense too. so keeping it black will probably go with the colour scheme better. It would be nice if I had thought this one through a little better. The next hexagon enclosures will be a bit different, and incorprate all the improvements I have learned with this project.

Here is some really nice stuff I just acquired off E-Bay for a very nice price.

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It is "Yew" and it is loaded with cluster burls. It's fairly light and perfectly highlights the burls. Unfortunately the sap at the corners will not be there when trimmed down, but it should prove to be a nice looking veneer should I decide to use it with a hexagon enclosure. I also have another order coming which will also will be good for a follow-up project.
 
Disabled Account
Joined 2007
Interesting looking veneer. Not my thing, but appeals to many.

I'm not sure why you want to make the cap (baffle) removable. I'd trim down the sides flush with the top, fill any gaps around with body filler and veneer it. I think it would look better that way - more modern, professional.
Speakers, like cars, used to have lots of trim on them. It's all about clean lines now though.

Just my own unsolicited personal view and opinion.:)
 
MJL21193 said:


Just my own unsolicited personal view and opinion.:)

I know, and that is why I solicit it, unlike some others here. ;)

Here is why I want it to be removable. I like to tinker with things, and the B20 may not be the perfect driver for this unit. And perhaps I may wish to upgrade to the Fostex 207. Who knows? Also, I may wish to go to a larger driver, which a 2.75 cu ft enclosure would allow.

I would much rather have a flexible enclosure than be locked in to just one thing. Besides, the pluses of being flexible far outweigh the negatives of rigidity, IMO.

BTY, if a unique cluster burl does not 'float your boat', what does?

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Is this "Wormey Maple" too light in the loafers for you? :)

I have to confess that I am not a big fan of dark woods much anymore. That is why walnut is one of my least favorite woods. It's just too bland for me, and overrated IMO. I like variety.

What does excite your visual aroma? And perhaps others can give their opinions too. This thread is about more than just the speakers in the speaker enclosures.
 
Disabled Account
Joined 2007
I actually like plain, straight grain, with no defects or figure the most. I like the shimmer of tiger strip maple in the right place (not an expansive panel).
I have a good appreciation of quarter sawn oak, especially white oak. I like black walnut, but only the heartwood. American cherry has nice features that can add character to a piece - spalts and wavy grain.
I want my projects to have subtle beauty, not a full on visual assault. Sometimes the veneer choice can really be too much, especially on a complex project.
 
John,

You could simply create a new baffle to sit on top of the one you have already that overlaps your rabit joint. It could mdf that you paint black or even a contrasting solid hardwood, if you are not worried about splitting.

If 3/4", that would allow you to cut some chamfers on that baffle, sort of like Duevel does on theirs and like I did on my first 13" square omni (mine were about 2" x 1/2"). It could easily glued to the other pieces or held with screws or bolts with hurricane nuts imbedded in your original bafle. The original baffle could even be glued into the box that way, since the new baffle would be removable. You could also cut the hole in the original baffle about larger so that you would be able to add a new top baffle anytime you want and grow the driver in size. It would also give the driver a little more breathing room this way, since the combined baffle depth would be pretty thick.

Just some food for thought.
 
Thanks Dan. If things don't work out for me, I will give it a go, and do something akin to what you and John are recommending.

I feel very comfortable with P/L, have worked with it for several years in commercial construction, and know a lot about it's strengths and weaknesses.

I went to Lowes and checked out the price on several types of Wilson Art and Formica P/L today, and the minimum size requirements are quite a bit. With one, I have to purchase at least a 36" x 96" sheet , and the other the minimum is a 48" x 96" piece. The prices run from $58 to $74. That is far too much for what I am willing to plank out at this time for just two baffle tops.

However, I already have several nice pieces of P/L in other colours and finishes. What I will probably do is make a rough cut, and use contact cememt to adhere it to the cap. Then trim the piece, and lightly sand the surface, to help paint stick better to the plastic. Then spray paint it with the same black I am using on the base.

Keep in mind that the P/L is very stiff, and a 3/8" overlap will be very sturdy, thin, and the edge can match the top, and not overwhelm the veneered sides. I'll give it a try, and if I have problems, I can always fall back on your recommendations. But I can't do anything today, as I still have snow on my back deck, and it is a balmy 32.7F here in Raleigh. Not the best weather to be out working on contact cement, that's for certain.;) :D


BTY, I also like those chamfers too, but I am worried about the placement of the driver, and mounting the tweeter on the modified phase plug. If I'm not careful, it will stick so far out that the diffusion horn will have to be set too far upward.

What I am really thinking about is perhaps recessing the driver below the baffle. Since the diffuser would be doing the dispersion, would recessing the driver hurt it's performance?
 
MJL21193 said:
Have you considered edge banding? It comes in black. Just iron it on and trim it.

I have John. In fact that is the first thing I went looking for locally. Unfortunately, I could only find the white banding. I had intended to look on the internet and order some, but came up with this P/L idea first.

The problem with the trim banding would be that I would need to trim off at least half of it, because the black just doesn't look all that nice if it is wide.

I'm still thinking of all my options with that.
 
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