Attached is a picture from the build with the parts laid out as intended. Behind the woofer I glued a roof tile, filled the slits with some glue before I bent them to shape and glued them on the braces, then added some bitumen on the surfaces. Should have braced more at the bottom, but the 'legs' I glued on the front actually helped to stiffen that up later. As you can see, the baffle pieces are too narrow, so I ended up making separate 'fill pieces' for the sides. First time I built a complicated shape like this, a little bit over my skill level..
Something I learned after is that a bit asymmetrical bracing can be good to 'diffuse' the resonances in the cabinet too. If the un-braced surfaces are equal, they are likely to have equal resonances.
I think it will be a lot easier if you make a flat back, you can then make the baffle with bracing first, and only put on the flat back in the end. This way you can do all the reinforcing/bracing/bitumen after the baffle has been glued to its final shape.
As you see, the mid cabinet is square, which I regret afterwards.
I had to fill with a lot of damping in the top and bottom to kill a standing wave in the speaker (looking at woofer impedance plot). It's not easy to do that once it's glued together.. Maybe you can play around with that before you permanently glue the back.
I run mine sealed, to my ears the group delay from BR does not sound good. The room helps with lifting the low end response, so it's pretty good in room without EQ. One way to deal with a too small cabinet could be a resistive port ('variovent') or possibly a large series cap on the woofer, but that adds group delay too, and loads the amp more.
Thanks great help broaden my view an consider some options
I checked the price of this woofer. It is a bit high. Almost double.
Im still sure about the backside. I checked if I would make some kind of triangle support in the back 20cm wide, 15cm deep and 50cm high.
Internal volume will go up with 1,2 L not that much as what I was hoping for. It will break internal reflextions.
I want to try to keep the aesthetics of a slim panel.
Maybe more for the mid?
Edit: looking at it again, I would say the diff is there for the woofer too, abt 1dB over a wide range. That energy is radiated forward instead of back to the wall behind the speaker, which reflections are later causing interference with the direct sound.
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If you are planning to tilt the speaker, maybe you could have a 'tapered' vertical rear panel, so the speaker is deeper in the bottom end?Thanks great help broaden my view an consider some options
I checked the price of this woofer. It is a bit high. Almost double.
Im still sure about the backside. I checked if I would make some kind of triangle support in the back 20cm wide, 15cm deep and 50cm high.
Internal volume will go up with 1,2 L not that much as what I was hoping for. It will break internal reflextions.
I want to try to keep the aesthetics of a slim panel.
WOW nice. You made a lot of slits to bend the sides. Troels only put 2 or 3.
A straight back would be an option. But then you loose the aesthetics of a narrow panel which for me is the beauty of this design.
Im also a bit scared that this box is over my skill level. But don't know yet what is the limit, so time to test it
.If I would fail completely, I could still reuse the drivers in a classic box.
That was an option I considered too. But it ruin the aesthetics. Or it should be only in the middle of the speaker not spanning over the complete width and roughly halve way to the height. But this way I don't gain much extra volume.
It would make it more stable though.
Yes, I then sanded and painted the outside with some epoxy paint and sanded again to make it perfectly rounded and also adding some strength with the epoxy.
Measured raw frequency response from the drivers is super smooth on this baffle, never seen anything like it! Using the DXT tweeter also gave me good time alignment with the mid. LR2 acoustical slopes. This is the 3rd version of it, I used a standard tweeter first, -was not happy with the result, then I tried to time align by making an extra baffle for woofer and mid, but that screwed up the FR, so I went back to standard flat baffle and bought the DXT tweeter, and everything fell into place.
Measured raw frequency response from the drivers is super smooth on this baffle, never seen anything like it! Using the DXT tweeter also gave me good time alignment with the mid. LR2 acoustical slopes. This is the 3rd version of it, I used a standard tweeter first, -was not happy with the result, then I tried to time align by making an extra baffle for woofer and mid, but that screwed up the FR, so I went back to standard flat baffle and bought the DXT tweeter, and everything fell into place.
It for sure will be a test for my skills.
This was my first build. Never did any woodwork before. Build it in the bathroom with minimum tools. Bought a router in the end to make the driver cut outs. Detachable front and back. White sides, top and bottom is more narrow on the front then on the back. Which gave it a nicer look.
I hope that making the baffle tilted would be good for time alignment. There is a 3D printed waveguide for this tweeter. But Im not sure if it would add more complexity for me. It could make the woodwork simpler. then I can go for a straight design iso slanted one.
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Looks like a nice build! I doubt you will be able to make the PMS in the bathroom though.. Pieces get fairly large.
Maybe you should leave it to a professional, or if you can engage a friend with some more space, like a garage? There will be a lot of cutting which equals a lot of dust, and it helps to get the pieces cut to exact dimensions with a good saw.
For the braces, I made one template by hand, and then used the router to cut the others from that template. I don't think it's harder to make the rear rounded as the front, it just takes more time. Trying some strange shapes for the rear could be just as complicated and time consuming. If you make some mistakes, you can use those pieces for the rear. I would actually make two mirrored pieces, front and rear, like split in half. Than you can have full access to the inside of both panels after they are glued to shape, and put the bitumen etc, and then glue the halves together when everything is perfect.
I used some 'synthetic leather' (can't remember the word in English) to cover the rear, looks nice and saved me a lot of time. Front is only covered with self adhesive plastic that looks like wood. Looks ok, as long as the surface is smooth, and it's easy to change the appearance of the speaker by replacing it. Make sure to have a painted surface though, or it will probably destroy the MDF surface when you tare it off.
Maybe you should leave it to a professional, or if you can engage a friend with some more space, like a garage? There will be a lot of cutting which equals a lot of dust, and it helps to get the pieces cut to exact dimensions with a good saw.
For the braces, I made one template by hand, and then used the router to cut the others from that template. I don't think it's harder to make the rear rounded as the front, it just takes more time. Trying some strange shapes for the rear could be just as complicated and time consuming. If you make some mistakes, you can use those pieces for the rear. I would actually make two mirrored pieces, front and rear, like split in half. Than you can have full access to the inside of both panels after they are glued to shape, and put the bitumen etc, and then glue the halves together when everything is perfect.
I used some 'synthetic leather' (can't remember the word in English) to cover the rear, looks nice and saved me a lot of time. Front is only covered with self adhesive plastic that looks like wood. Looks ok, as long as the surface is smooth, and it's easy to change the appearance of the speaker by replacing it. Make sure to have a painted surface though, or it will probably destroy the MDF surface when you tare it off.
I will consider a professional to make some work for me. Just need to figure out most before i start so i can give proper instructions. Exactly what I though..if front and back are the same, use the nice ones for the front...but then i need to have nice ones
During my previous build discovered there are some woodshops around where you can use their tools for small money. They intention is "team building" but individuals are welcome too.
Im considering synthetic leather too. Looks nice. good tips.
Im building confidence here 
Does it have to stay round? I was thinking to put an aluminium profile on the sides.
Backside shape is irrelevant considering radiation. at least vertical edges should have some rounding, but evevn that is not so critical in a wide baffle. Curved front panel looks damn good in my eyes. I have been dreaming about Stradivari copies, but I don't have big enough room for them.
Kimmosto made a Stradivari clone about 15 years ago with triangle crossection.. He has now hidden his speaker projects from the web.
Kimmosto made a Stradivari clone about 15 years ago with triangle crossection.. He has now hidden his speaker projects from the web.
Sharing, just in case it helps,
Here is a wide baffle 2 way design: https://drive.google.com/file/d/1Pug0AA54HXHrcQgFjCLT0sXs-sVI0MlS/view
Here is Kimmosto's wide baffle 3 way design: https://web.archive.org/web/20170906120644/http://kimmosaunisto.net/KS-483/KS-483.html
Thanks
Vineeth
Here is a wide baffle 2 way design: https://drive.google.com/file/d/1Pug0AA54HXHrcQgFjCLT0sXs-sVI0MlS/view
Here is Kimmosto's wide baffle 3 way design: https://web.archive.org/web/20170906120644/http://kimmosaunisto.net/KS-483/KS-483.html
Thanks
Vineeth
Maybe it is the scale that makes it look so different to expected, attached is an overlay of closed and vented in Vituix.
An inner sealed box for the mid and tweeter seems like it would leave more than 25 litres for a tall wide speaker. Long ports suffer greater resonances too so the shorter the better. You could build it in a way to try both sealed and ported as options.
Regarding the waveguide, here is thread that you might find interesting, different cabinet and 2 way but some inspiration perhaps.
https://www.audiosciencereview.com/.../revel-m105-copy-diy-build.29465/post-1029858
Irrelevant is not a good word, the whole shape of a speaker cabinet has an effect on the radiation pattern. It takes a considerable number of measurements or 3D simulation to show it though.
Attachments
I really like this shape. Is there an example how to make the woodwork?
I was thinking to make slits in the MDF panel and then bend it. Guess needs some slits close together when approaching the ends.
some example where I can learn from would be very helpfull.
Hornresp (sticky thread in subwoofers) can make the curve and can give you data for woodworking.
The method is called kerfing..
https://www.woodworkingarchive.biz/kerf-bending/kerf-spacing.html
The method is called kerfing..
https://www.woodworkingarchive.biz/kerf-bending/kerf-spacing.html
Thanks.
This really helps.
I was thinking I figured things out....but then...
When opening to the community, different views and approaches are offered. Just what I was looking for.
But now need to rethink things again...
I like the 2-way design. Actually the cabinet size/volume is similar like to what I was planning. But they use a 6.5"driver and 2-way design.
Maybe Im pushing it too much to make a 3-way in the same volume and use 8"woofer?
My room is quiet big now...5.5mx8mx3m but planning to move to smaller place in the future. Livingroom will be 5X6X2.6m then. Medium size? Dont know if I need 8"woofer.
I got some confidence in how to build the cabinet. But after seeing kimmosto version...
.
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