Bend radius of 1/4" (6mm) MDF

[LarryM]

From my venture into curved surfaces:
Last year I built a 1400 array with a 4.2cu ft volume and slightly curved sides. I too was vexed with how to curve plywood. I tried 1/2" bendy plywood, but it is so flimsy and full of voids, I gave up on that idea. Instead I constructed a trapezoid out of 18mm Baltic birch and to create the curve, cut thin strips of varying thickness to fill in the sides. The top and bottom plywood is cut with the correct curve. Strips fill in across the curve, positioned for the correct fit. If the strip was too thin or thick, I just made another one. The covering was 1/8" Baltic birch glued and nailed down. For the SAM1HF to get the sharp curve, I used 1/8" bendy ply although I had to search the poor quality sheet for the best section.

I too would like to have used the 2216, but the LE14 works fine. I am happy with the results.

In your case, cut the side as two separate pieces. For the curved portion, lay the strips as I did to create the slight curve you need. Cover with 1/8" plywood or whatever you desire.
A few photos attached; side, looking down through the bottom and finished view.

[Ed Zeppeli]

Nice looking project Larry and thanks for the information. As you can see in my picture above my baffles are already cut to the contour so I will have to try getting the bend with laminated layers of MDF. 1/4" may work and 1/8" will definitely work but that's a lot more layers.

What are you using to crossover your Array clones?

Cheers,

Warren

[LarryM]

Hi Warren,

My crossovers were divided into 3 sections; LF mounted in bottom backside of cabinet, MF below the 435al and HF below the 045ti. They are CC'd, battery mounted on the back next to the SpeakON connector.

I reused some of the components on the SAM1HF crossover. Many coils and resistors are the same values as the 1400 array. I think a couple of coils had to be unwound a bit. Resistors were either the same wattage or more.

The parts were really a pain to remove from the PCB. The board is plated on both sides and thru-holes too. The copper seemed like it was 2oz, but I may be wrong on that. Basically, you need a high wattage iron.

[JeffW]

That's nice work!

[Ed Zeppeli]

Nice indeed. I was just going to use the internal SAM1HF crossover with an analogue crossover for the bottom end until I get a good DSP to go full active. I never did see any technical information on how the Array crossover differed from the SAM1HF other than anecdotal 'voiced for home theatre' comments.

What is the distance between the bottom of the horn and the top of the woofer? (if you don't mind)

Anyway, excellent project and thanks for sharing.

[Lee in Montreal]

Looking at the picture, I can see that the transition between the flat side into the curved part is not smooth. That will make bending any type of wood a nightmare.

[Ed Zeppeli]

Yes I will have to deal with that. I will either sand some radius into it or put a small kerf in the side at the transition point.

Thanks,

Warren

[LarryM]

Nice indeed. I was just going to use the internal SAM1HF crossover with an analogue crossover for the bottom end until I get a good DSP to go full active. I never did see any technical information on how the Array crossover differed from the SAM1HF other than anecdotal 'voiced for home theatre' comments.

What is the distance between the bottom of the horn and the top of the woofer? (if you don't mind)

Anyway, excellent project and thanks for sharing.

Sorry, I forgot to reply. The array 1400 has something like 1-1/2" to 2" vertical distance bottom of horn to top of woofer. Someone measured it here on the forum, but I can't find it. Mine is almost 3". Also the SAM1 is forward of the baffle a bit. About 1/2" from woofer baffle to the horn/enclosure joint (where the SAM1 horn meets the box).

I seem to remember someone here tried to use the stock SAM1HF as is (stock crossover). It is too bright for the LE14H. The array 1400 accounts for this, but if you switch to the 2216nd, it will be more efficient by about 6db. You will have to deal with that. For now using the LE14, you could modify the stock SAM crossover by removing/changing the components. It is actually quite similar to the 1400. Search for 'SAM1HF schematic', it is all there. I estimated about $50 to convert to a 1400 crossover. You would need an inductance meter to unwind a few coils and of course the LF section is all new anyway no matter what you do.

This is a fun a rewarding project, I think you will be pleased. I had a 250ti made from a L250, it is the same bottom end 1400, but the 1400 mid and top end is much better.
Good luck,
Larry

[Ed Zeppeli]

Thanks Larry. The sensitivity issue makes sense, which as you mentioned, would likely be mostly taken care of in my case with a higher sensitivity woofer plus the active (analogue) crossover.

I was just back-checking some of the Array threads here and found that someone posted the distance from horn to edge of speaker and the horn offset over the front when viewed from the side. 38mm (or 1 1/2") for both.

Interesting that the crossover can be modified for about $50. I'll have to sharpen my schematic reading skills.

Cheers,

Warren

[Ed Zeppeli]

My ports will be in front on my bass modules and I'd appreciate some feedback regarding spacing. I made a dummy panel to sit in front so I could get a visual. I split the width in half then centered the ports within their half but they look like they could come together a bit to my eyes.

They look huge but it's the flare. ID = 4"

Thanks

[Ed Zeppeli]

Boxes are functionally complete. I will be veneering the bottom half of the baffle around the ports and the sides. The dado halfway down the baffle will be wood trim, likely stained red.



Currently I'm bi-amping them using an old Rane analogue crossover into the SAM1HF crossover up top; crossed over at about 800Hz. They sound lovely with the 2234Hs I have in there now. I can't wait to DSP them in the room. Also, it looks like the 2216ND will just drop in as it measures within 1/64th for recessed mounting and the bolt centres are basically the same.

There is a nasty buzzing coming out of one of the 2234s in the dustcap area which I will have to investigate further. I have spare caps if I have to cut one out.

Oh, the bends took 5 layers of 1/8" MDF to get around that corner.

I will keep posting updates here for posterity!

[grumpy]

Awesome... you made them your own.

[Ed Zeppeli]

Awesome... you made them your own.

Thanks. It's certainly been an experiment.

Beauty is in the ear of the beholder.

[Ed Zeppeli]

Finally (almost) done this project. Toughest woodworking I've done. I didn't realize what I was getting into with the curved sides.

Speakon connectors and jumpers to the HF module. Still some polishing/fine sanding to do.



Please don't mind the mess. Mid project, you know.





Looking forward to biamping them with DSP, looking at the dbx venu360.

[JeffW]

I don't know how I missed the finished product shot, just noticed your avatar and went for a peek. I'd say your bending experiment turned out very well.